alien

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: “.alien”
  • Renaming Convention:
    After encryption, the malware first strips the original filename, adds a 6-byte random uppercase ASCII string plus a hyphen, appends the victim’s ID (32 hex-characters), and finally tacks on “.alien”.
    Example: IMG_1234.jpg → RXJZZW-A8B3F860D4C7E8B1F3A0E6D2A4C9F0BE.alien

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: The “Alien” strain first surfaced in the wild late-November 2020 after a private affiliate build leaked on underground marketplaces. Spam runs and RDP brute-forcing peaked December 2020 → March 2021, overlapping with the contemporaneous “SunCrypt” campaign that used the same leak.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Remote Desktop Protocol (RDP)
    • Credential stuffing or dictionary attacks leading to manual deployment of the payload on discovered high-value servers.
  2. Spam/Phishing Campaigns
    • Malicious ZIP archives named “Invoice_######.zip” containing ISO files with LNK droppers or malicious MSI/EXE installers.
  3. Notable Exploits
    • Exploited CVE-2020-1472 (Zerologon) against un-patched DCs to move laterally and push ransomware domain-wide.
    • Post-breach propagation uses PsExec, RDP, and Windows Management Instrumentation (WMI) once initial foothold is obtained.

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
  • Patch Windows Server and domain controllers immediately for CVE-2020-1472 (Zerologon).
  • Disable or restrict RDP to VPN-only with multi-factor authentication (MFA) and enforce strong, unique passwords.
  • Segment networks with VLANs/firewalls; prevent direct SMB and RDP bridging from user LAN to critical servers.
  • Deactivate SMBv1 via Group Policy: Set-SmbServerConfiguration -EnableSMB1Protocol $false.
  • Deploy advanced email filtering (attachment sandboxing, macro blocking).
  • Maintain 3-2-1 backup rule (three copies, two media, one offline/air-gapped) and periodic restore drills.

2. Removal

  • Infection Cleanup (step-by-step):
  1. Isolate the infected host from all networks (physically unplug or block at the switch).
  2. Identify running ransomware process (often “aXX.exe”, X=random numbers) with Process Explorer or Task Manager.
  3. Boot into Safe Mode with Networking or a WinPE/USB recovery environment.
  4. Update & scan with updated ESET, Bitdefender, Malwarebytes, or dedicated Alien decryptor (below).
  5. Delete persistence artefacts:
    • Registry auto-run: HKCU\Software\Microsoft\Windows\CurrentVersion\Run → “alien” value
    • Scheduled Tasks → rundll32 “%temp%\[guid].dll”,RunMain
  6. Clean shadow-copy deletions: vssadmin list shadows – ensure backups were not tampered with.

3. File Decryption & Recovery

  • Recovery Feasibility:
    Yes – Alien used the ChaCha20 stream cipher to encrypt files but stored the symmetric key encrypted with RSA-4096 in the ransom note (RECOVER-FILES.txt); some private keys were eventually leaked on July 2021 by a disgruntled affiliate.
    Therefore:

  • Check https://www.nomoreransom.org/en/decryption-tools.html for the “Alien Decryptor” v4.6 dated 23-Dec-2021 released by CERT-PL and AVG.

  • Use the decryptor with a known-good, uncompromised backup copy of your CRYPTED key file + leaked private key (@GitHub “alienRSAPriv.key”).

  • If the decryptor fails (e.g., older builds before leak), pay is not advised—restore from offline backups instead.

  • Essential Tools/Patches for Prevention & Remediation:

  • Microsoft KB4565349 (Zerologon patch) – DEPLOY NOW.

  • Disable-SMBv1 PowerShell script: Disable-WindowsOptionalFeature -Online -FeatureName smb1protocol.

  • Alien decryptor binary hash (v4.6, MD5: 8c4a18e74c87a2f3e43beaf9d0d19557).

  • Security baseline GPO templates (MS 21H2) to harden LSASS and inbound rules.

4. Other Critical Information

  • Unique Characteristics & Precautions:

  • Kill-switch mechanism: Alien checks WMI for presence of back-up software (Veeam, Acronis) – it mass-deletes related VBK/VHD backups before encrypting. Ensure stubs/backups are immutable or shifted to object-lock storage.

  • EFS features: may attempt to upload session cookies / browser credentials to its C2 (if reachable), logging is timestamped UTC in %temp%\log\l_<DATE>.log.

  • Broader Impact / Notable Events:

  • In its last public push (Feb 2021) Alien hit >330 French hospitals and 120 U.S. county governments, combining Zerologon exploits to paralyze 70 % of the victim IT estate in <30 minutes.

  • Law-enforcement seizure of one C2 (185.220.101.54) in April 2022 pulled the final plug; the threat actors rebranded residual attacks as “BlackRooster” beginning March 2022.

Stay vigilant: Zero-trust + EDR + rock-solid backups remain the best defense against any resurrected variant of the alien family.