Category: alerts

Citrix has released security updates addressing vulnerabilities in Citrix Hypervisor 8.2 CU1 LTSR. A cyber threat actor could exploit these vulnerabilities to take control of an affected system.

CISA encourages users and administrators to review Citrix Hypervisor Security Bulletin for CVE-2023-23583 and CVE-2023-46835 and apply the necessary updates.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Today, the Federal Bureau of Investigation (FBI) and the Cybersecurity and Infrastructure Security Agency (CISA) released a joint Cybersecurity Advisory (CSA) on Scattered Spider—a cybercriminal group targeting commercial facilities sectors and subsectors. The advisory provides tactics, techniques, and procedures (TTPs) obtained through FBI investigations as recently as November 2023.

Scattered Spider threat actors typically engage in data theft for extortion using multiple social engineering techniques and have recently leveraged BlackCat/ALPHV ransomware alongside their usual TTPs.

FBI and CISA encourage network defenders and critical infrastructure organizations to review the joint CSA for recommended mitigations to reduce the likelihood and impact of a cyberattack by Scattered Spider actors. For more information, visit StopRansomware and see the updated #StopRansomware Guide.

SUMMARY

The Federal Bureau of Investigation (FBI) and Cybersecurity and Infrastructure Security Agency (CISA) are releasing this joint Cybersecurity Advisory (CSA) in response to recent activity by Scattered Spider threat actors against the commercial facilities sectors and subsectors. This advisory provides tactics, techniques, and procedures (TTPs) obtained through FBI investigations as recently as November 2023.

Scattered Spider is a cybercriminal group that targets large companies and their contracted information technology (IT) help desks. Scattered Spider threat actors, per trusted third parties, have typically engaged in data theft for extortion and have also been known to utilize BlackCat/ALPHV ransomware alongside their usual TTPs.

The FBI and CISA encourage critical infrastructure organizations to implement the recommendations in the Mitigations section of this CSA to reduce the likelihood and impact of a cyberattack by Scattered Spider actors.

Download the PDF version of this report:

TECHNICAL DETAILS

Note: This advisory uses the MITRE ATT&CK for Enterprise framework, version 14. See the MITRE ATT&CK^® Tactics and Techniques section for a table of the threat actors’ activity mapped to MITRE ATT&CK tactics and techniques. For assistance with mapping malicious cyber activity to the MITRE ATT&CK framework, see CISA and MITRE ATT&CK’s Best Practices for MITRE ATT&CK Mapping and CISA’s Decider Tool.

Overview

Scattered Spider (also known as Starfraud, UNC3944, Scatter Swine, and Muddled Libra) engages in data extortion and several other criminal activities.[1] Scattered Spider threat actors are considered experts in social engineering and use multiple social engineering techniques, especially phishing, push bombing, and subscriber identity module (SIM) swap attacks, to obtain credentials, install remote access tools, and/or bypass multi-factor authentication (MFA). According to public reporting, Scattered Spider threat actors have [2],[3],[4]:

• Posed as company IT and/or helpdesk staff using phone calls or SMS messages to obtain credentials from employees and gain access to the network [T1598],[T1656].
• Posed as company IT and/or helpdesk staff to direct employees to run commercial remote access tools enabling initial access [T1204],[T1219],[T1566].
• Posed as IT staff to convince employees to share their one-time password (OTP), an MFA authentication code.
• Sent repeated MFA notification prompts leading to employees pressing the “Accept” button (also known as MFA fatigue) [T1621].[5]
• Convinced cellular carriers to transfer control of a targeted user’s phone number to a SIM card they controlled, gaining control over the phone and access to MFA prompts.
• Monetized access to victim networks in numerous ways including extortion enabled by ransomware and data theft [T1657].

After gaining access to networks, FBI observed Scattered Spider threat actors using publicly available, legitimate remote access tunneling tools. Table 1 details a list of legitimate tools Scattered Spider, repurposed and used for their criminal activity. Note: The use of these legitimate tools alone is not indicative of criminal activity. Users should review the Scattered Spider indicators of compromise (IOCs) and TTPs discussed in this CSA to determine whether they have been compromised.

Table 1: Legitimate Tools Used by Scattered Spider

Tool	Intended Use
Fleetdeck.io	Enables remote monitoring and management of systems.
Level.io	Enables remote monitoring and management of systems.
Mimikatz [S0002]	Extracts credentials from a system.
Ngrok [S0508]	Enables remote access to a local web server by tunneling over the internet.
Pulseway	Enables remote monitoring and management of systems.
Screenconnect	Enables remote connections to network devices for management.
Splashtop	Enables remote connections to network devices for management.
Tactical.RMM	Enables remote monitoring and management of systems.
Tailscale	Provides virtual private networks (VPNs) to secure network communications.
Teamviewer	Enables remote connections to network devices for management.

In addition to using legitimate tools, Scattered Spider also uses malware as part of its TTPs. See Table 2 for some of the malware used by Scattered Spider.

Table 2: Malware Used by Scattered Spider

Malware	Use
AveMaria (also known as WarZone [S0670])	Enables remote access to a victim’s systems.
Raccoon Stealer	Steals information including login credentials [TA0006], browser history [T1217], cookies [T1539], and other data.
VIDAR Stealer	Steals information including login credentials, browser history, cookies, and other data.

Scattered Spider threat actors have historically evaded detection on target networks by using living off the land techniques and allowlisted applications to navigate victim networks, as well as frequently modifying their TTPs.

Observably, Scattered Spider threat actors have exfiltrated data [TA0010] after gaining access and threatened to release it without deploying ransomware; this includes exfiltration to multiple sites including U.S.-based data centers and MEGA[.]NZ [T1567.002].

Recent Scattered Spider TTPs

New TTP – File Encryption

More recently, the FBI has identified Scattered Spider threat actors now encrypting victim files after exfiltration [T1486]. After exfiltrating and/or encrypting data, Scattered Spider threat actors communicate with victims via TOR, Tox, email, or encrypted applications.

Reconnaissance, Resource Development, and Initial Access

Scattered Spider intrusions often begin with broad phishing [T1566] and smishing [T1660] attempts against a target using victim-specific crafted domains, such as the domains listed in Table 3 [T1583.001].

Table 3: Domains Used by Scattered Spider Threat Actors

Domains
victimname-sso[.]com
victimname-servicedesk[.]com
victimname-okta[.]com

In most instances, Scattered Spider threat actors conduct SIM swapping attacks against users that respond to the phishing/smishing attempt. The threat actors then work to identify the personally identifiable information (PII) of the most valuable users that succumbed to the phishing/smishing, obtaining answers for those users’ security questions. After identifying usernames, passwords, PII [T1589], and conducting SIM swaps, the threat actors then use social engineering techniques [T1656] to convince IT help desk personnel to reset passwords and/or MFA tokens [T1078.002],[T1199],[T1566.004] to perform account takeovers against the users in single sign-on (SSO) environments.

Execution, Persistence, and Privilege Escalation

Scattered Spider threat actors then register their own MFA tokens [T1556.006],[T1606] after compromising a user’s account to establish persistence [TA0003]. Further, the threat actors add a federated identity provider to the victim’s SSO tenant and activate automatic account linking [T1484.002]. The threat actors are then able to sign into any account by using a matching SSO account attribute. At this stage, the Scattered Spider threat actors already control the identity provider and then can choose an arbitrary value for this account attribute. As a result, this activity allows the threat actors to perform privileged escalation [TA0004] and continue logging in even when passwords are changed [T1078]. Additionally, they leverage common endpoint detection and response (EDR) tools installed on the victim networks to take advantage of the tools’ remote-shell capabilities and executing of commands which elevates their access. They also deploy remote monitoring and management (RMM) tools [T1219] to then maintain persistence.

Discovery, Lateral Movement, and Exfiltration

Once persistence is established on a target network, Scattered Spider threat actors often perform discovery, specifically searching for SharePoint sites [T1213.002], credential storage documentation [T1552.001], VMware vCenter infrastructure [T1018], backups, and instructions for setting up/logging into Virtual Private Networks (VPN) [TA0007]. The threat actors enumerate the victim’s Active Directory (AD), perform discovery and exfiltration of victim’s code repositories [T1213.003], code-signing certificates [T1552.004], and source code [T1083],[TA0010]. Threat actors activate Amazon Web Services (AWS) Systems Manager Inventory [T1538] to discover targets for lateral movement [TA0007],[TA0008], then move to both preexisting [T1021.007] and actor-created [T1578.002] Amazon Elastic Compute Cloud (EC2) instances. In instances where the ultimate goal is data exfiltration, Scattered Spider threat actors use actor-installed extract, transform, and load (ETL) tools [T1648] to bring data from multiple data sources into a centralized database [T1074],[T1530]. According to trusted third parties, where more recent incidents are concerned, Scattered Spider threat actors may have deployed BlackCat/ALPHV ransomware onto victim networks—thereby encrypting VMware Elastic Sky X integrated (ESXi) servers [T1486].

To determine if their activities have been uncovered and maintain persistence, Scattered Spider threat actors often search the victim’s Slack, Microsoft Teams, and Microsoft Exchange online for emails [T1114] or conversations regarding the threat actor’s intrusion and any security response. The threat actors frequently join incident remediation and response calls and teleconferences, likely to identify how security teams are hunting them and proactively develop new avenues of intrusion in response to victim defenses. This is sometimes achieved by creating new identities in the environment [T1136] and is often upheld with fake social media profiles [T1585.001] to backstop newly created identities.

MITRE ATT&CK TACTICS AND TECHNIQUES

See Tables 4 through 17 for all referenced threat actor tactics and techniques in this advisory.

Table 4: Reconnaissance

Technique Title	ID	Use
Gather Victim Identity Information	T1589	Scattered Spider threat actors gather usernames, passwords, and PII for targeted organizations.
Phishing for Information	T1598	Scattered Spider threat actors use phishing to obtain login credentials, gaining access to a victim’s network.

Table 5: Resource Development

Technique Title	ID	Use
Acquire Infrastructure: Domains	T1583.001	Scattered Spider threat actors create domains for use in phishing and smishing attempts against targeted organizations.
Establish Accounts: Social Media Accounts	T1585.001	Scattered Spider threat actors create fake social media profiles to backstop newly created user accounts in a targeted organization.

Table 6: Initial Access

Technique Title	ID	Use
Phishing	T1566	Scattered Spider threat actors use broad phishing attempts against a target to obtain information used to gain initial access. Scattered Spider threat actors have posed as helpdesk personnel to direct employees to install commercial remote access tools.
Phishing (Mobile)	T1660	Scattered Spider threat actors send SMS messages, known as smishing, when targeting a victim.
Phishing: Spearphishing Voice	T1566.004	Scattered Spider threat actors use voice communications to convince IT help desk personnel to reset passwords and/or MFA tokens.
Trusted Relationship	T1199	Scattered Spider threat actors abuse trusted relationships of contracted IT help desks to gain access to targeted organizations.
Valid Accounts: Domain Accounts	T1078.002	Scattered Spider threat actors obtain access to valid domain accounts to gain initial access to a targeted organization.

Table 7: Execution

Technique Title	ID	Use
Serverless Execution	T1648	Scattered Spider threat actors use ETL tools to collect data in cloud environments.
User Execution	T1204	Scattered Spider threat actors impersonating helpdesk personnel direct employees to run commercial remote access tools thereby enabling access to the victim’s network.

Table 8: Persistence

Technique Title	ID	Use
Persistence	TA0003	Scattered Spider threat actors seek to maintain persistence on a targeted organization’s network.
Create Account	T1136	Scattered Spider threat actors create new user identities in the targeted organization.
Modify Authentication Process: Multi-Factor Authentication	T1556.006	Scattered Spider threat actors may modify MFA tokens to gain access to a victim’s network.
Valid Accounts	T1078	Scattered Spider threat actors abuse and control valid accounts to maintain network access even when passwords are changed.

Table 9: Privilege Escalation

Technique Title	ID	Use
Privilege Escalation	TA0004	Scattered Spider threat actors escalate account privileges when on a targeted organization’s network.
Domain Policy Modification: Domain Trust Modification	T1484.002	Scattered Spider threat actors add a federated identify provider to the victim’s SSO tenant and activate automatic account linking.

Table 10: Defense Evasion

Technique Title	ID	Use
Modify Cloud Compute Infrastructure: Create Cloud Instance	T1578.002	Scattered Spider threat actors will create cloud instances for use during lateral movement and data collection.
Impersonation	TA1656	Scattered Spider threat actors pose as company IT and/or helpdesk staff to gain access to victim’s networks. Scattered Spider threat actors use social engineering to convince IT help desk personnel to reset passwords and/or MFA tokens.

Table 11: Credential Access

Technique Title	ID	Use
Credential Access	TA0006	Scattered Spider threat actors use tools, such as Raccoon Stealer, to obtain login credentials.
Forge Web Credentials	T1606	Scattered Spider threat actors may forge MFA tokens to gain access to a victim’s network.
Multi-Factor Authentication Request Generation	T1621	Scattered Spider sends repeated MFA notification prompts to lead employees to accept the prompt and gain access to the target network.
Unsecured Credentials: Credentials in Files	T1552.001	Scattered Spider threat actors search for insecurely stored credentials on victim’s systems.
Unsecured Credentials: Private Keys	T1552.004	Scattered Spider threat actors search for insecurely stored private keys on victim’s systems.

Table 12: Discovery

Technique Title	ID	Use
Discovery	TA0007	Upon gaining access to a targeted network, Scattered Spider threat actors seek out SharePoint sites, credential storage documentation, VMware vCenter, infrastructure backups and enumerate AD to identify useful information to support further operations.
Browser Information Discovery	T1217	Scattered Spider threat actors use tools (e.g., Raccoon Stealer) to obtain browser histories.
Cloud Service Dashboard	T1538	Scattered Spider threat actors leverage AWS Systems Manager Inventory to discover targets for lateral movement.
File and Directory Discovery	T1083	Scattered Spider threat actors search a compromised network to discover files and directories for further information or exploitation.
Remote System Discovery	T1018	Scattered Spider threat actors search for infrastructure, such as remote systems, to exploit.
Steal Web Session Cookie	T1539	Scattered Spider threat actors use tools, such as Raccoon Stealer, to obtain browser cookies.

Table 13: Lateral Movement

Technique Title	ID	Use
Lateral Movement	TA0008	Scattered Spider threat actors laterally move across a target network upon gaining access and establishing persistence.
Remote Services: Cloud Services	T1021.007	Scattered Spider threat actors use pre-existing cloud instances for lateral movement and data collection.

Table 14: Collection

Technique Title	ID	Use
Data from Information Repositories: Code Repositories	T1213.003	Scattered Spider threat actors search code repositories for data collection and exfiltration.
Data from Information Repositories: Sharepoint	T1213.002	Scattered Spider threat actors search SharePoint repositories for information.
Data Staged	T1074	Scattered Spider threat actors stage data from multiple data sources into a centralized database before exfiltration.
Email Collection	T1114	Scattered Spider threat actors search victim’s emails to determine if the victim has detected the intrusion and initiated any security response.
Data from Cloud Storage	T1530	Scattered Spider threat actors search data in cloud storage for collection and exfiltration.

Table 15: Command and Control

Technique Title	ID	Use
Remote Access Software	T1219	Impersonating helpdesk personnel, Scattered Spider threat actors direct employees to run commercial remote access tools thereby enabling access to and command and control of the victim’s network. Scattered Spider threat actors leverage third-party software to facilitate lateral movement and maintain persistence on a target organization’s network.

Table 16: Exfiltration

Technique Title	ID	Use
Exfiltration	TA0010	Scattered Spider threat actors exfiltrate data from a target network to for data extortion.

Table 17: Impact

Technique Title	ID	Use
Data Encrypted for Impact	T1486	Scattered Spider threat actors recently began encrypting data on a target network and demanding a ransom for decryption. Scattered Spider threat actors has been observed encrypting VMware ESXi servers.
Exfiltration Over Web Service: Exfiltration to Cloud Storage	T1567.002	Scattered Spider threat actors exfiltrate data to multiple sites including U.S.-based data centers and MEGA[.]NZ.
Financial Theft	T1657	Scattered Spider threat actors monetized access to victim networks in numerous ways including extortion-enabled ransomware and data theft.

MITIGATIONS

These mitigations apply to all critical infrastructure organizations and network defenders. The FBI and CISA recommend that software manufactures incorporate secure-by-design and -default principles and tactics into their software development practices limiting the impact of ransomware techniques, thus, strengthening the secure posture for their customers.

For more information on secure by design, see CISA’s Secure by Design and Default webpage and joint guide.

The FBI and CISA recommend organizations implement the mitigations below to improve your organization’s cybersecurity posture based on the threat actor activity and to reduce the risk of compromise by Scattered Spider threat actors. These mitigations align with the Cross-Sector Cybersecurity Performance Goals (CPGs) developed by CISA and the National Institute of Standards and Technology (NIST). The CPGs provide a minimum set of practices and protections that CISA and NIST recommend all organizations implement. CISA and NIST based the CPGs on existing cybersecurity frameworks and guidance to protect against the most common and impactful threats, tactics, techniques, and procedures. Visit CISA’s Cross-Sector Cybersecurity Performance Goals for more information on the CPGs, including additional recommended baseline protections.

• Implement application controls to manage and control execution of software, including allowlisting remote access programs. Application controls should prevent installation and execution of portable versions of unauthorized remote access and other software. A properly configured application allowlisting solution will block any unlisted application execution. Allowlisting is important because antivirus solutions may fail to detect the execution of malicious portable executables when the files use any combination of compression, encryption, or obfuscation.
• Reduce threat of malicious actors using remote access tools by:
  • Auditing remote access tools on your network to identify currently used and/or authorized software.
  • Reviewing logs for execution of remote access software to detect abnormal use of programs running as a portable executable [CPG 2.T].
  • Using security software to detect instances of remote access software being loaded only in memory.
  • Requiring authorized remote access solutions to be used only from within your network over approved remote access solutions, such as virtual private networks (VPNs) or virtual desktop interfaces (VDIs).
  • Blocking both inbound and outbound connections on common remote access software ports and protocols at the network perimeter.
  • Applying recommendations in the Guide to Securing Remote Access Software.
• Implementing FIDO/WebAuthn authentication or Public Key Infrastructure (PKI)-based MFA. These MFA implementations are resistant to phishing and not suspectable to push bombing or SIM swap attacks, which are techniques known to be used by Scattered Spider actors. See CISA’s fact sheet Implementing Phishing-Resistant MFA for more information.
• Strictly limit the use of Remote Desktop Protocol (RDP) and other remote desktop services. If RDP is necessary, rigorously apply best practices, for example [CPG 2.W]:
  • Audit the network for systems using RDP.
  • Close unused RDP ports.
  • Enforce account lockouts after a specified number of attempts.
  • Apply phishing-resistant multifactor authentication (MFA).
  • Log RDP login attempts.

In addition, the authoring authorities of this CSA recommend network defenders apply the following mitigations to limit potential adversarial use of common system and network discovery techniques, and to reduce the impact and risk of compromise by ransomware or data extortion actors:

• Implement a recovery plan to maintain and retain multiple copies of sensitive or proprietary data and servers in a physically separate, segmented, and secure location (i.e., hard drive, storage device, the cloud).
• Maintain offline backups of data and regularly maintain backup and restoration (daily or weekly at minimum). By instituting this practice, an organization limits the severity of disruption to its business practices [CPG 2.R].
• Require all accounts with password logins (e.g., service account, admin accounts, and domain admin accounts) to comply with NIST’s standards for developing and managing password policies.
  • Use longer passwords consisting of at least eight characters and no more than 64 characters in length [CPG 2.B].
  • Store passwords in hashed format using industry-recognized password managers.
  • Add password user “salts” to shared login credentials.
  • Avoid reusing passwords [CPG 2.C].
  • Implement multiple failed login attempt account lockouts [CPG 2.G].
  • Disable password “hints.”
  • Refrain from requiring password changes more frequently than once per year.
    Note: NIST guidance suggests favoring longer passwords instead of requiring regular and frequent password resets. Frequent password resets are more likely to result in users developing password “patterns” cyber criminals can easily decipher.
  • Require administrator credentials to install software.
• Require phishing-resistant multifactor authentication (MFA) for all services to the extent possible, particularly for webmail, virtual private networks (VPNs), and accounts that access critical systems [CPG 2.H].
• Keep all operating systems, software, and firmware up to date. Timely patching is one of the most efficient and cost-effective steps an organization can take to minimize its exposure to cybersecurity threats. Prioritize patching known exploited vulnerabilities in internet-facing systems [CPG 1.E].
• Segment networks to prevent the spread of ransomware. Network segmentation can help prevent the spread of ransomware by controlling traffic flows between—and access to—various subnetworks and by restricting adversary lateral movement [CPG 2.F].
• Identify, detect, and investigate abnormal activity and potential traversal of the indicated ransomware with a networking monitoring tool. To aid in detecting the ransomware, implement a tool that logs and reports all network traffic and activity, including lateral movement, on a network. Endpoint detection and response (EDR) tools are particularly useful for detecting lateral connections as they have insight into common and uncommon network connections for each host [CPG 3.A].
• Install, regularly update, and enable real time detection for antivirus software on all hosts.
• Disable unused ports and protocols [CPG 2.V].
• Consider adding an email banner to emails received from outside your organization [CPG 2.M].
• Disable hyperlinks in received emails.
• Ensure all backup data is encrypted, immutable (i.e., ensure backup data cannot be altered or deleted), and covers the entire organization’s data infrastructure [CPG 2.K, 2.L, 2.R].

VALIDATE SECURITY CONTROLS

In addition to applying mitigations, FBI and CISA 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 FBI and CISA 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 Tables 4-17).
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.

FBI and CISA 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.

REPORTING

FBI and CISA are seeking any information that can be shared, to include a sample ransom note, communications with Scattered Spider group actors, Bitcoin wallet information, decryptor files, and/or a benign sample of an encrypted file. FBI and CISA do not encourage paying ransom as payment does not guarantee victim files 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. Regardless of whether you or your organization have decided to pay the ransom, FBI and CISA urge you to promptly report ransomware incidents to a local FBI Field Office, report the incident to the FBI Internet Crime Complaint Center (IC3) at IC3.gov, or CISA via CISA’s 24/7 Operations Center (report@cisa.gov or 888-282-0870).

REFERENCES

[1] MITRE ATT&CK – Scattered Spider
[2] Trellix – Scattered Spider: The Modus Operandi
[3] Crowdstrike – Not a SIMulation: CrowdStrike Investigations Reveal Intrusion Campaign Targeting Telco and BPO Companies
[4] Crowdstrike – SCATTERED SPIDER Exploits Windows Security Deficiencies with Bring-Your-Own-Vulnerable-Driver Tactic in Attempt to Bypass Endpoint Security
[5] Malwarebytes – Ransomware group steps up, issues statement over MGM Resorts compromise

DISCLAIMER

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

VERSION HISTORY

November 16, 2023: Initial version.

Today, the Cybersecurity and Infrastructure Security Agency (CISA), the Federal Bureau of Investigation (FBI), and the Multi-State Information Sharing and Analysis Center (MS-ISAC) released a joint Cybersecurity Advisory (CSA), #StopRansomware: Rhysida Ransomware, to disseminate known Rhysida ransomware indicators of compromise (IOCs), detection methods, and tactics, techniques, and procedures (TTPs) identified through investigations as recently as September 2023.

Observed as a ransomware-as-a-service (RaaS) model, Rhysida actors have compromised organizations in education, manufacturing, information technology, and government sectors and any ransom paid are split between the group and affiliates. Rhysida actors leverage external-facing remote services, such as virtual private networks (VPNs), Zerologon vulnerability (CVE-2020-1472), and phishing campaigns to gain initial access and persistence within a network.

CISA, FBI, and MS-ISAC encourage organizations review the joint CSA for recommended mitigations to reduce the likelihood and impact of Rhysida and other ransomware incidents. For more information, see CISA’s #StopRansomware webpage, which includes the updated #StopRansomware Guide.

SUMMARY

Note: This joint Cybersecurity Advisory (CSA) is part of an ongoing #StopRansomware effort to publish advisories for network defenders detailing 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 the Multi-State Information Sharing and Analysis Center (MS-ISAC) are releasing this joint CSA to disseminate known Rhysida ransomware IOCs and TTPs identified through investigations as recently as September 2023. Rhysida—an emerging ransomware variant—has predominately been deployed against the education, healthcare, manufacturing, information technology, and government sectors since May 2023. The information in this CSA is derived from related incident response investigations and malware analysis of samples discovered on victim networks.

FBI, CISA, and the MS-ISAC encourage organizations to implement the recommendations in the Mitigations section of this CSA to reduce the likelihood and impact of Rhysida ransomware and other ransomware incidents.

Download the PDF version of this report:

TECHNICAL DETAILS

Note: This advisory uses the MITRE ATT&CK® for Enterprise framework, version 14. See the ATT&CK Tactics and Techniques section for tables mapped to the threat actors’ activity.

Overview

Threat actors leveraging Rhysida ransomware are known to impact “targets of opportunity,” including victims in the education, healthcare, manufacturing, information technology, and government sectors. Open source reporting details similarities between Vice Society (DEV-0832)[1] activity and the actors observed deploying Rhysida ransomware. Additionally, open source reporting[2] has confirmed observed instances of Rhysida actors operating in a ransomware-as-a-service (RaaS) capacity, where ransomware tools and infrastructure are leased out in a profit-sharing model. Any ransoms paid are then split between the group and the affiliates.

For additional information on Vice Society actors and associated activity, see the joint CSA #StopRansomware: Vice Society.

Initial Access

Rhysida actors have been observed leveraging external-facing remote services to initially access and persist within a network. Remote services, such as virtual private networks (VPNs), allow users to connect to internal enterprise network resources from external locations. Rhysida actors have commonly been observed authenticating to internal VPN access points with compromised valid credentials [T1078], notably due to organizations lacking MFA enabled by default. Additionally, actors have been observed exploiting Zerologon (CVE-2020-1472)—a critical elevation of privileges vulnerability in Microsoft’s Netlogon Remote Protocol [T1190]—as well as conducting successful phishing attempts [T1566]. Note: Microsoft released a patch for CVE-2020-1472 on August 11, 2020.[3]

Living off the Land

Analysis identified Rhysida actors using living off the land techniques, such as creating Remote Desktop Protocol (RDP) connections for lateral movement [T1021.001], establishing VPN access, and utilizing PowerShell [T1059.001]. Living off the land techniques include using native (built into the operating system) network administration tools to perform operations. This allows the actors to evade detection by blending in with normal Windows systems and network activities.

Ipconfig [T1016], whoami [T1033], nltest [T1482], and several net commands have been used to enumerate victim environments and gather information about domains. In one instance of using compromised credentials, actors leveraged net commands within PowerShell to identify logged-in users and performed reconnaissance on network accounts within the victim environment. Note: The following commands were not performed in the exact order listed.

• net user [username] /domain [T1087.002]
• net group “domain computers” /domain [T1018]
• net group “domain admins” /domain [T1069.002]
• net localgroup administrators [T1069.001]

Analysis of the master file table (MFT)[4] identified the victim system generated the ntuser.dat registry hive, which was created when the compromised user logged in to the system for the first time. This was considered anomalous due to the baseline of normal activity for that particular user and system. Note: The MFT resides within the New Technology File System (NTFS) and houses information about a file including its size, time and date stamps, permissions, and data content.

Leveraged Tools

Table 1 lists legitimate tools Rhysida actors have repurposed for their operations. The legitimate tools listed in this joint CSA are all publicly available. Use of these tools should not be attributed as malicious without analytical evidence to support they are used at the direction of or controlled by threat actors.

Disclaimer: Organizations are encouraged to investigate and vet use of these tools prior to performing remediation actions.

Table 1: Tools Leveraged by Rhysida Actors

Name	Description
cmd.exe	The native command line prompt utility.
PowerShell.exe	A native command line tool used to start a Windows PowerShell session in a Command Prompt window.
PsExec.exe	A tool included in the PsTools suite used to execute processes remotely. Rhysida actors heavily leveraged this tool for lateral movement and remote execution.
mstsc.exe	A native tool that establishes an RDP connection to a host.
PuTTY.exe	Rhysida actors have been observed creating Secure Shell (SSH) PuTTy connections for lateral movement. In one example, analysis of PowerShell console host history for a compromised user account revealed Rhysida actors leveraged PuTTy to remotely connect to systems via SSH [T1021.004].
PortStarter	A back door script written in Go that provides functionality for modifying firewall settings and opening ports to pre-configured command and control (C2) servers.[1]
secretsdump	A script used to extract credentials and other confidential information from a system. Rhysida actors have been observed using this for NTDS dumping [T1003.003] in various instances.
ntdsutil.exe	A standard Windows tool used to interact with the NTDS database. Rhysida actors used this tool to extract and dump the NTDS.dit database from the domain controller containing hashes for all Active Directory (AD) users. Note: It is strongly recommended that organizations conduct domain-wide password resets and double Kerberos TGT password resets if any indication is found that the NTDS.dit file was compromised.
AnyDesk	A common software that can be maliciously used by threat actors to obtain remote access and maintain persistence [T1219]. AnyDesk also supports remote file transfer.
wevtutil.exe	A standard Windows Event Utility tool used to view event logs. Rhysida actors used this tool to clear a significant number of Windows event logs, including system, application, and security logs [T1070.001].
PowerView	A PowerShell tool used to gain situational awareness of Windows domains. Review of PowerShell event logs identified Rhysida actors using this tool to conduct additional reconnaissance-based commands and harvest credentials.

Rhysida Ransomware Characteristics

Execution

In one investigation, Rhysida actors created two folders in the C: drive labeled in and out, which served as a staging directory (central location) for hosting malicious executables. The in folder contained file names in accordance with host names on the victim’s network, likely imported through a scanning tool. The out folder contained various files listed in Table 2 below. Rhysida actors deployed these tools and scripts to assist system and network-wide encryption.

Table 2: Malicious Executables Affiliated with Rhysida Infections

File Name	Hash (SHA256)	Description
conhost.exe	6633fa85bb234a75927b23417313e51a4c155e12f71da3959e168851a600b010	A ransomware binary.
psexec.exe	078163d5c16f64caa5a14784323fd51451b8c831c73396b967b4e35e6879937b	A file used to execute a process on a remote or local host.
S_0.bat	1c4978cd5d750a2985da9b58db137fc74d28422f1e087fd77642faa7efe7b597	A batch script likely used to place 1.ps1 on victim systems for ransomware staging purposes [T1059.003].
1.ps1	4e34b9442f825a16d7f6557193426ae7a18899ed46d3b896f6e4357367276183	Identifies an extension block list of files to encrypt and not encrypt.
S_1.bat	97766464d0f2f91b82b557ac656ab82e15cae7896b1d8c98632ca53c15cf06c4	A batch script that copies conhost.exe (the encryption binary) on an imported list of host names within the C:WindowsTemp directory of each system.
S_2.bat	918784e25bd24192ce4e999538be96898558660659e3c624a5f27857784cd7e1	Executes conhost.exe on compromised victim systems, which encrypts and appends the extension of .Rhysida across the environment.

Rhysida ransomware uses a Windows 64-bit Portable Executable (PE) or common object file format (COFF) compiled using MinGW via the GNU Compiler Collection (GCC), which supports various programming languages such as C, C++, and Go. The cryptographic ransomware application first injects the PE into running processes on the compromised system [T1055.002]. Additionally, third-party researchers identified evidence of Rhysida actors developing custom tools with program names set to “Rhysida-0.1” [T1587].

Encryption

After mapping the network, the ransomware encrypts data using a 4096-bit RSA encryption key with a ChaCha20 algorithm [T1486]. The algorithm features a 256-bit key, a 32-bit counter, and a 96-bit nonce along with a four-by-four matrix of 32-bit words in plain text. Registry modification commands [T1112] are not obfuscated, displayed as plain-text strings and executed via cmd.exe.

Rhysida’s encryptor runs a file to encrypt and modify all encrypted files to display a .rhysida extension.[5] Following encryption, a PowerShell command deletes the binary [T1070.004] from the network using a hidden command window [T1564.003]. The Rhysida encryptor allows arguments -d (select a directory) and -sr (file deletion), defined by the authors of the code as parseOptions.[6] After the lines of binary strings complete their tasks, they delete themselves through the control panel to evade detection.

Data Extortion

Rhysida actors reportedly engage in “double extortion” [T1657]—demanding a ransom payment to decrypt victim data and threatening to publish the sensitive exfiltrated data unless the ransom is paid.[5],[7] Rhysida actors direct victims to send ransom payments in Bitcoin to cryptocurrency wallet addresses provided by the threat actors. As shown in Figure 1, Rhysida ransomware drops a ransom note named “CriticalBreachDetected” as a PDF file—the note provides each company with a unique code and instructions to contact the group via a Tor-based portal.

Identified in analysis and also listed in open source reporting, the contents of the ransom note are embedded as plain-text in the ransom binary, offering network defenders an opportunity to deploy string-based detection for alerting on evidence of the ransom note. Rhysida threat actors may target systems that do not use command-line operating systems. The format of the PDF ransom notes could indicate that Rhysida actors only target systems that are compatible with handling PDF documents.[8]

INDICATORS OF COMPROMISE

On November 10, 2023, Sophos published TTPs and IOCs identified from analysis conducted for six separate incidents.[9] The C2 IP addresses listed in Table 3 were derived directly from Sophos’ investigations and are listed on GitHub among other indicators.[10]

Table 3: C2 IP Addresses Used for Rhysida Operations

C2 IP Address
5.39.222[.]67
5.255.99[.]59
51.77.102[.]106
108.62.118[.]136
108.62.141[.]161
146.70.104[.]249
156.96.62[.]58
157.154.194[.]6

Additional IOCs were obtained from FBI, CISA, and the MS-ISAC’s investigations and analysis. The email addresses listed in Table 4 are associated with Rhysida actors’ operations. Rhysida actors have been observed creating Onion Mail email accounts for services or victim communication, commonly in the format: [First Name][Last Name]@onionmail[.]org.

Table 4: Email Addresses Used to Support Rhysida Operations

Email Address
rhysidaeverywhere@onionmail[.]org
rhysidaofficial@onionmail[.]org

Rhysida actors have also been observed using the following files and executables listed in Table 5 to support their operations.

Disclaimer: Organizations are encouraged to investigate the use of these files for related signs of compromise prior to performing remediation actions.

Table 5: Files Used to Support Rhysida Operations

File Name	Hash (SHA256)
Sock5.sh	48f559e00c472d9ffe3965ab92c6d298f8fb3a3f0d6d203cd2069bfca4bf3a57
PsExec64.exe	edfae1a69522f87b12c6dac3225d930e4848832e3c551ee1e7d31736bf4525ef
PsExec.exe	078163d5c16f64caa5a14784323fd51451b8c831c73396b967b4e35e6879937b
PsGetsid64.exe	201d8e77ccc2575d910d47042a986480b1da28cf0033e7ee726ad9d45ccf4daa
PsGetsid.exe	a48ac157609888471bf8578fb8b2aef6b0068f7e0742fccf2e0e288b0b2cfdfb
PsInfo64.exe	de73b73eeb156f877de61f4a6975d06759292ed69f31aaf06c9811f3311e03e7
PsInfo.exe	951b1b5fd5cb13cde159cebc7c60465587e2061363d1d8847ab78b6c4fba7501
PsLoggedon64.exe	fdadb6e15c52c41a31e3c22659dd490d5b616e017d1b1aa6070008ce09ed27ea
PsLoggedon.exe	d689cb1dbd2e4c06cd15e51a6871c406c595790ddcdcd7dc8d0401c7183720ef
PsService64.exe	554f523914cdbaed8b17527170502199c185bd69a41c81102c50dbb0e5e5a78d
PsService.exe	d3a816fe5d545a80e4639b34b90d92d1039eb71ef59e6e81b3c0e043a45b751c
Eula.txt	8329bcbadc7f81539a4969ca13f0be5b8eb7652b912324a1926fc9bfb6ec005a
psfile64.exe	be922312978a53c92a49fefd2c9f9cc098767b36f0e4d2e829d24725df65bc21
psfile.exe	4243dc8b991f5f8b3c0f233ca2110a1e03a1d716c3f51e88faf1d59b8242d329
pskill64.exe	7ba47558c99e18c2c6449be804b5e765c48d3a70ceaa04c1e0fae67ff1d7178d
pskill.exe	5ef168f83b55d2cbd2426afc5e6fa8161270fa6a2a312831332dc472c95dfa42
pslist64.exe	d3247f03dcd7b9335344ebba76a0b92370f32f1cb0e480c734da52db2bd8df60
pslist.exe	ed05f5d462767b3986583188000143f0eb24f7d89605523a28950e72e6b9039a
psloglist64.exe	5e55b4caf47a248a10abd009617684e969dbe5c448d087ee8178262aaab68636
psloglist.exe	dcdb9bd39b6014434190a9949dedf633726fdb470e95cc47cdaa47c1964b969f
pspasswd64.exe	8d950068f46a04e77ad6637c680cccf5d703a1828fbd6bdca513268af4f2170f
pspasswd.exe	6ed5d50cf9d07db73eaa92c5405f6b1bf670028c602c605dfa7d4fcb80ef0801
psping64.exe	d1f718d219930e57794bdadf9dda61406294b0759038cef282f7544b44b92285
psping.exe	355b4a82313074999bd8fa1332b1ed00034e63bd2a0d0367e2622f35d75cf140
psshutdown64.exe	4226738489c2a67852d51dbf96574f33e44e509bc265b950d495da79bb457400
psshutdown.exe	13fd3ad690c73cf0ad26c6716d4e9d1581b47c22fb7518b1d3bf9cfb8f9e9123
pssuspend64.exe	4bf8fbb7db583e1aacbf36c5f740d012c8321f221066cc68107031bd8b6bc1ee
pssuspend.exe	95a922e178075fb771066db4ab1bd70c7016f794709d514ab1c7f11500f016cd
PSTools.zip	a9ca77dfe03ce15004157727bb43ba66f00ceb215362c9b3d199f000edaa8d61
Pstools.chm	2813b6c07d17d25670163e0f66453b42d2f157bf2e42007806ebc6bb9d114acc
psversion.txt	8e43d1ddbd5c129055528a93f1e3fab0ecdf73a8a7ba9713dc4c3e216d7e5db4
psexesvc.exe	This artifact is created when a user establishes a connection using psexec. It is removed after the connection is terminated, which is why there is no hash available for this executable.

MITRE ATT&CK TACTICS AND TECHNIQUES

See Tables 6-15 for all referenced threat actor tactics and techniques in this advisory. For assistance with mapping malicious cyber activity to the MITRE ATT&CK framework, see CISA and MITRE’s Best Practices for MITRE ATT&CK Mapping and CISA’s Decider Tool.

Additional notable TTPs have been published by the Check Point Incident Response Team.[11]

Table 6: Resource Development

Technique Title	ID	Use
Develop Capabilities	T1587	Rhysida actors have been observed developing resources and custom tools, particularly with program names set to “Rhysida-0.1” to gain access to victim systems.

Table 7: Initial Access

Technique Title	ID	Use
Valid Accounts	T1078	Rhysida actors are known to use valid credentials to access internal VPN access points of victims.
Exploit Public-Facing Application	T1190	Rhysida actors have been identified exploiting Zerologon, a critical elevation of privilege vulnerability within Microsoft’s Netlogon Remote Protocol.
Phishing	T1566	Rhysida actors are known to conduct successful phishing attacks.

Table 8: Execution

Technique Title	ID	Use
Command and Scripting Interpreter: PowerShell	T1059.001	Rhysida actors used PowerShell commands (ipconfig, nltest, net) and various scripts to execute malicious actions.
Command and Scripting Interpreter: Windows Command Shell	T1059.003	Rhysida actors used batch scripting to place 1.ps1 on victim systems to automate ransomware execution.

Table 9: Privilege Escalation

Technique Title	ID	Use
Process Injection: Portable Executable Injection	T1055.002	Rhysida actors injected a Windows 64-bit PE cryptographic ransomware application into running processes on compromised systems.

Table 10: Defense Evasion

Technique Title	ID	Use
Indicator Removal: Clear Windows Event Logs	T1070.001	Rhysida actors used wevtutil.exe to clear Windows event logs, including system, application, and security logs.
Indicator Removal: File Deletion	T1070.004	Rhysida actors used PowerShell commands to delete binary strings.
Hide Artifacts: Hidden Window	T1564.003	Rhysida actors have executed hidden PowerShell windows.

Table 11: Credential Access

Technique Title	ID	Use
OS Credential Dumping: NTDS	T1003.003	Rhysida actors have been observed using secretsdump to extract credentials and other confidential information from a system, then dumping NTDS credentials.
Modify Registry	T1112	Rhysida actors were observed running registry modification commands via cmd.exe.

Table 12: Discovery

Technique Title	ID	Use
System Network Configuration Discovery	T1016	Rhysida actors used the ipconfig command to enumerate victim system network settings.
Remote System Discovery	T1018	Rhysida actors used the command net group “domain computers” /domain to enumerate servers on a victim domain.
System Owner/User Discovery	T1033	Rhysida actors leveraged whoami and various net commands within PowerShell to identify logged-in users.
Permission Groups Discovery: Local Groups	T1069.001	Rhysida actors used the command net localgroup administrators to identify accounts with local administrator rights.
Permission Groups Discovery: Domain Groups	T1069.002	Rhysida actors used the command net group “domain admins” /domain to identify domain administrators.
Account Discovery: Domain Account	T1087.002	Rhysida actors used the command net user [username] /domain to identify account information.
Domain Trust Discovery	T1482	Rhysida actors used the Windows utility nltest to enumerate domain trusts.

Table 13: Lateral Movement

Technique Title	ID	Use
Remote Services: Remote Desktop Protocol	T1021.001	Rhysida actors are known to use RDP for lateral movement.
Remote Services: SSH	T1021.004	Rhysida actors used compromised user credentials to leverage PuTTy and remotely connect to victim systems via SSH.

Table 14: Command and Control

Technique Title	ID	Use
Remote Access Software	T1219	Rhysida actors have been observed using the AnyDesk software to obtain remote access to victim systems and maintain persistence.

Table 15: Impact

Technique Title	ID	Use
Data Encrypted for Impact	T1486	Rhysida actors encrypted victim data using a 4096-bit RSA encryption key that implements a ChaCha20 algorithm.
Financial Theft	T1657	Rhysida actors reportedly engage in “double extortion”— demanding a ransom payment to decrypt victim data and threatening to publish the sensitive exfiltrated data unless the ransom is paid.

MITIGATIONS

FBI, CISA, and the MS-ISAC recommend that organizations implement the mitigations below to improve your organization’s cybersecurity posture. These mitigations align with the Cross-Sector Cybersecurity Performance Goals (CPGs) developed by CISA and the National Institute of Standards and Technology (NIST). The CPGs provide a minimum set of practices and protections that CISA and NIST recommend all organizations implement. CISA and NIST based the CPGs on existing cybersecurity frameworks and guidance to protect against the most common and impactful threats, and TTPs. Visit CISA’s Cross-Sector Cybersecurity Performance Goals for more information on the CPGs, including additional recommended baseline protections.

These mitigations apply to all critical infrastructure organizations and network defenders. FBI, CISA, and the MS-ISAC recommend incorporating secure-by-design and -default principles, limiting the impact of ransomware techniques and strengthening overall security posture. For more information on secure by design, see CISA’s Secure by Design webpage.

• Require phishing-resistant MFA for all services to the extent possible, particularly for webmail, VPN, and accounts that access critical systems [CPG 2.H].
• Disable command-line and scripting activities and permissions. Privilege escalation and lateral movement often depend on software utilities running from the command line. If threat actors are not able to run these tools, they will have difficulty escalating privileges and/or moving laterally [CPG 2.N].
• Implement verbose and enhanced logging within processes such as command line auditing[12] and process tracking[13].
• Restrict the use of PowerShell using Group Policy and only grant access to specific users on a case-by-case basis. Typically, only those users or administrators who manage the network or Windows operating systems should be permitted to use PowerShell [CPG 2.E].
• Update Windows PowerShell or PowerShell Core to the latest version and uninstall all earlier PowerShell versions. Logs from Windows PowerShell prior to version 5.0 are either non-existent or do not record enough detail to aid in enterprise monitoring and incident response activities [CPG 1.E, 2.S, 2.T].
• Enable enhanced PowerShell logging [CPG 2.T, 2.U].
  • PowerShell logs contain valuable data, including historical operating system and registry interaction and possible TTPs of a threat actor’s PowerShell use.
  • Ensure PowerShell instances (using the latest version) have module, script block, and transcription logging enabled (e.g., enhanced logging).
  • The two logs that record PowerShell activity are the PowerShell Windows event log and the PowerShell operational log. FBI, CISA, and the MS-ISAC recommend turning on these two Windows event logs with a retention period of at least 180 days. These logs should be checked on a regular basis to confirm whether the log data has been deleted or logging has been turned off. Set the storage size permitted for both logs to as large as possible.
• Restrict the use of RDP and other remote desktop services to known user accounts and groups. If RDP is necessary, apply best practices such as [CPG 2.W]:
  • Implement MFA for privileged accounts using RDP.
  • Use Remote Credential Guard[14] to protect credentials, particularly domain administrator or other high value accounts.
  • Audit the network for systems using RDP.
  • Close unused RDP ports.
  • Enforce account lockouts after a specified number of attempts.
  • Log RDP login attempts.
• Secure remote access tools by:
  • Implementing application controls to manage and control execution of software, including allowlisting remote access programs. Application controls should prevent the installation and execution of portable versions of unauthorized remote access and other software. A properly configured application allowlisting solution will block any unlisted application execution. Allowlisting is important as antivirus solutions may fail to detect the execution of malicious portable executables when the files use any combination of compression, encryption, or obfuscation.
  • Apply the recommendations in CISA’s joint Guide to Securing Remote Access Software.

In addition, FBI, CISA, and the MS-ISAC recommend network defenders apply the following mitigations to limit potential adversarial use of common system and network discovery techniques, and to reduce the impact and risk of compromise by ransomware or data extortion actors:

• Keep all operating systems, software, and firmware up to date. Timely patching is one of the most efficient and cost-effective steps an organization can take to minimize its exposure to cybersecurity threats. Prioritize patching known exploited vulnerabilities in internet-facing systems [CPG 1.E].
• Segment networks to prevent the spread of ransomware. Network segmentation can help prevent the spread of ransomware by controlling traffic flows between—and access to—various subnetworks and by restricting adversary lateral movement [CPG 2.F].
• Identify, detect, and investigate abnormal activity and potential traversal of the indicated ransomware with a network monitoring tool. To aid in detecting ransomware, implement a tool that logs and reports all network traffic, including lateral movement activity on a network. Endpoint detection and response (EDR) tools are particularly useful for detecting lateral connections as they have insight into common and uncommon network connections for each host [CPG 3.A].
• Audit user accounts with administrative privileges and configure access controls according to the principle of least privilege (PoLP) [CPG 2.E].
• Implement time-based access for accounts set at the admin level and higher [CPG 2.A, 2.E]. For example, the just-in-time (JIT) access method provisions privileged access when needed and can support the enforcement of PoLP (as well as the zero trust model). This is a process where a network-wide policy is set in place to automatically disable admin accounts at the AD level when the account is not in direct need. Individual users may submit their requests through an automated process that grants them access to a specified system for a set timeframe when they need to support the completion of a certain task.
• Implement a recovery plan to maintain and retain multiple copies of sensitive or proprietary data and servers in a physically separate, segmented, and secure location (e.g., hard drive, storage device, or the cloud).
• Maintain offline backups of data and regularly maintain backups and their restoration (daily or weekly at minimum). By instituting this practice, organizations limit the severity of disruption to business operations [CPG 2.R].
• Ensure all backup data is encrypted, immutable (i.e., cannot be altered or deleted), and covers the entire organization’s data infrastructure [CPG 2.K, 2.L, 2.R].
• Forward log files to a hardened centralized logging server, preferably on a segmented network [CPG 2.F]. Review logging retention rates, such as for VPNs and network-based logs.

• Consider adding an email banner to emails received from outside your organization [CPG 2.M].
• Disable hyperlinks in received emails.

VALIDATE SECURITY CONTROLS

In addition to applying mitigations, FBI, CISA, and the MS-ISAC 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. FBI, CISA, and the MS-ISAC 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 Tables 6-15).
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.

FBI, CISA, and the MS-ISAC 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: #StopRansomware
• CISA: #StopRansomware Vice Society
• CISA: Known Exploited Vulnerabilities Catalog
• NIST: CVE-2020-1472
• CISA, MITRE: Best Practices for MITRE ATT&CK Mapping
• CISA: Decider Tool
• CISA: Cross-Sector Cybersecurity Performance Goals
• CISA: Secure by Design
• CISA: Implementing Phishing-Resistant MFA
• CISA: Guide to Securing Remote Access Software

REPORTING

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 Rhysida actors, Bitcoin wallet information, decryptor files, and/or a benign sample of an encrypted file.

Additional details requested include: a targeted company point of contact, status and scope of infection, estimated loss, operational impact, transaction IDs, date of infection, date detected, initial attack vector, and host and network-based indicators.

FBI and CISA do not encourage paying ransom as payment does not guarantee victim files will be recovered. Furthermore, payment may also embolden adversaries to target additional organizations, encourage other threat actors to engage in the distribution of ransomware, and/or fund illicit activities. Regardless of whether you or your organization have decided to pay the ransom, FBI and CISA urge you to promptly report ransomware incidents to the FBI’s Internet Crime Complaint Center (IC3) at Ic3.gov, a local FBI Field Office, or CISA via the agency’s Incident Reporting System or its 24/7 Operations Center at report@cisa.gov or (888) 282-0870.

REFERENCES

1. Microsoft: DEV-0832 (Vice Society) Opportunistic Ransomware Campaigns Impacting US Education Sector
2. FortiGuard Labs: Ransomware Roundup – Rhysida
3. Microsoft: Security Update Guide – CVE-2020-1472
4. Microsoft: Master File Table (Local File Systems)
5. SentinelOne: Rhysida
6. Secplicity: Scratching the Surface of Rhysida Ransomware
7. Cisco Talos: What Cisco Talos Knows about the Rhysida Ransomware
8. SOC Radar: Rhysida Ransomware Threat Profile
9. Sophos: A Threat Cluster’s Switch from Vice Society to Rhysida
10. Sophos: Vice Society – Rhysida IOCs (GitHub)
11. Check Point Research: Rhysida Ransomware – Activity and Ties to Vice Society
12. Microsoft: Command Line Process Auditing
13. Microsoft: Audit Process Tracking
14. Microsoft: Remote Credential Guard

ACKNOWLEDGEMENTS

Sophos contributed to this CSA.

DISCLAIMER

The information in this report is being provided “as is” for informational purposes only. FBI, CISA, and the MS-ISAC do not endorse any commercial entity, product, company, or service, including any entities, products, or services linked within this document. Any reference to specific commercial entities, products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring by FBI, CISA, and the MS-ISAC.

VERSION HISTORY

November 15, 2023: Initial version.

Today, the Australian Signals Directorate’s Australian Cyber Security Centre (ASD’s ACSC) and CISA released Business Continuity in a Box. Business Continuity in a Box, developed by ACSC with contributions from CISA, assists organizations with swiftly and securely standing up critical business functions during or following a cyber incident.

Comprised of two core components—Continuity of Communications and Continuity of Applications—Business Continuity in a Box is designed for situations where the availability or integrity of an organization’s data and/or systems has been compromised. The core components focus on keeping communications flowing during an incident and establishing interim business-critical applications.

Business Continuity in a Box aligns with CISA’s goals for Critical Infrastructure Security and Resilience Month which aims to provide businesses of all sizes with free or low-cost resources and tools that aid in strengthening our national cybersecurity posture.