McAfee Defender’s Blog: Cuba Ransomware Campaign

Keypoints

Cuba ransomware actors have adopted data dissemination (public leak) when ransoms are not paid, increasing exposure even after recovery.
The campaign’s initial access vector is unknown; likely methods include spearphishing, weaponized documents, signed binaries, or system tool abuse.
McAfee Insights and ATR provide CTI and IOCs; MVISION EDR enables rapid hunting, containment, and investigation from the console.
Recommended defenses span user awareness, email/web filtering, endpoint threat prevention (signature, ML, behavior), application control, and EDR sensors.
The article maps Cuba techniques to MITRE ATT&CK (execution, persistence, evasion, discovery, impact) and aligns McAfee product mitigations for each technique.
Published IOCs include file names, multiple email addresses, domains (including a TOR leak site), and many file hashes; YARA rules are available in the technical report.

MITRE Techniques

[T1566.001] Spearphishing Attachment – Used as a potential initial access vector. Quote: ‘Spear Phishing Attachments (T1566.001)’.
[T1566.002] Spearphishing Link – Used as a potential initial access vector. Quote: ‘Spear Phishing Link (T1566.002)’.
[T1566.003] Spearphishing via Service – Used as a potential initial access vector. Quote: ‘Spear Phishing (T1566.003) Service’.
[T1204] User Execution – Attack relies on user execution of malicious documents or attachments. Quote: ‘User Execution (T1204)’.
[T1059.001] Command and Scripting Interpreter: PowerShell – PowerShell payloads are used to drop Cuba ransomware. Quote: ‘Cuba team is using PowerShell payload to drop Cuba ransomware’.
[T1569.002] System Services: Service Execution – Service execution is noted as an execution mechanism. Quote: ‘System Services: Service Execution (T1569.002)’.
[T1129] Shared Modules – Ransomware links functions at runtime via shared modules. Quote: ‘Cuba ransomware links function at runtime’.
[T1059] Command and Scripting Interpreter – Ransomware accepts command line arguments and uses scripting for actions. Quote: ‘Cuba ransomware accepts command line arguments’.
[T1547] Boot or Autologon Execution – Used for persistence via boot/autologon mechanisms. Quote: ‘Boot or Autologon Execution (T1547)’.
[T1221] Template Injection – Template injection is used as an evasion/persistence technique. Quote: ‘Template Injection (T1221)’.
[T1218] Signed Binary Proxy Execution – Uses signed binaries to proxy execution and evade defenses. Quote: ‘Signed Binary Proxy Execution (T1218)’.
[T1027] Obfuscated Files or Information / Deobfuscate-Decode – Ransomware obfuscates data using XOR encoding. Quote: ‘Cuba ransomware is using xor algorithm to encode data’.
[T1543.003] Create or Modify System Process: Windows Service – Malware can create/modify services for persistence. Quote: ‘Create or Modify System Process: Windows Service (T1543.003)’.
[T1134] Access Token Manipulation – Ransomware adjusts privileges (SeDebugPrivilege, AdjustTokenPrivileges). Quote: ‘Cuba ransomware can adjust access privileges’.
[T1222] File and Directory Permissions Modification – Ransomware sets file attributes and modifies permissions. Quote: ‘Cuba ransomware will set file attributes’.
[T1083] File and Directory Discovery – Ransomware enumerates files to identify targets for encryption. Quote: ‘Cuba ransomware enumerates files’.
[T1057] Process Discovery – Ransomware enumerates process modules during discovery. Quote: ‘Cuba ransomware enumerates process modules’.
[T1082] System Information Discovery – Ransomware collects system info (keyboard layout, volumes, drives). Quote: ‘Cuba ransomware can get keyboard layout, enumerates disks, etc’.
[T1007] System Service Discovery – Ransomware queries service status for discovery. Quote: ‘Cuba ransomware can query service status’.
[T1056.001] Input Capture: Keylogging – Ransomware logs keystrokes via polling functions. Quote: ‘Cuba ransomware logs keystrokes via polling’.
[T1573] Encrypted Channel (C2) – Uses encrypted channels for command-and-control communications. Quote: ‘Encrypted Channel (T1573)’.
[T1489] Service Stop – Ransomware can stop services as part of impact. Quote: ‘Cuba ransomware can stop services’.
[T1486] Data Encrypted for Impact – Ransomware encrypts data to cause impact. Quote: ‘Cuba ransomware encrypts data’.

Indicators of Compromise

[File names] Deployment and scripts – 151.bat, Kurva.ps1 (examples of observed malicious files).
[Email addresses] Ransom/contact emails used by operators – [email protected], [email protected] (plus other addresses listed).
[Domains / Leak site] Abuse and leak infrastructure – kurvalarva[.]com, TOR leak site http://cuba4mp6ximo2zlo[.]onion/.
[File hashes] Malware & lateral movement scripts – c4b1f4e1ac9a28cc9e50195b29dde8bd54527abc7f4d16899f9f8315c852afd4, 54627975c0befee0075d6da1a53af9403f047d9e367389e48ae0d25c2a7154bc, and 20+ other hashes.

McAfee’s technical recommendations focus on rapid CTI ingestion, layered prevention, and EDR-enabled hunting. Begin by ingesting Cuba-specific indicators from McAfee Insights and the ATR report; apply signature, ML, and behavior-based protections at email gateways, web proxies, and endpoints (Threat Prevention, Adaptive Threat Protection, MWG/WGCS). Enforce secure configurations and application control (MAC), restrict admin privileges, and enable AMSI/anti-script integrations to reduce exposure to weaponized documents, PowerShell payloads, and signed-binary proxying.

During exploitation and impact phases, deploy MVISION EDR and MVISION Cloud for visibility into execution (PowerShell, cmdline args), persistence (service creation/modification), privilege escalation (token adjustments), discovery (file/process/system enumeration), and data encryption activities. Use EDR-driven hunts and playbooks to search for IOCs (file names, email indicators, domain/TOR endpoints, and hashes), apply containment actions from the console, and escalate to incident response workflows when indicators or anomalous behavior are found.

Operationalize detection by mapping telemetry to MITRE techniques (as enumerated above) and tuning detections for behaviors such as xor-based obfuscation, anti-VM checks, service manipulation, and keystroke polling. Publish YARA rules and include the provided hashes in threat feeds; instrument central logging and dashboards (ePO/MVISION) to monitor for Cuba-related events and to accelerate triage and remediation.

McAfee Defender’s Blog: Cuba Ransomware Campaign | McAfee Blog