alkohol

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: alkohol
  • Renaming Convention: Upon finishing encryption the ransomware renames every file to <original-name>.<random-5-char-string>.alkohol (example: Report Q1.xlsx.Wq9fZ.alkohol). Unlike many families it keeps the original file name intact and only appends two new parts, never touches extensions inside archives, and reverts NTFS “Last Write” timestamp back to the old value to frustrate recovery scripts that rely on file dates.

2. Detection & Outbreak Timeline

  • First In-the-Wild Appearance: The first public sightings and submissions to public sandboxes appeared 2024-03-11.
  • World-wide-spike: A sudden 400 % increase in telemetry was observed during the period 14 Mar – 22 Mar 2024 after the operator group began large-scale RDP brute-force campaigns using credentials harvested in earlier infostealer drops.

3. Primary Attack Vectors

| Vector | Details |
|—|—|
| Open / compromised RDP (3389/TCP) | Mirai-variant bot actively bruteforces weak passwords then hands the session to an “alkohol-loader.exe”. Once logged in the attacker executes a PowerShell one-liner and drops the final payload via bitsadmin. |
| Spear-phishing (ZIP → ISO/IMG) | Mail campaigns impersonate FedEx, DHL and German customs. Attachment contains a 2-level container invoice.iso → invoice.lnk which launches rundll32 to sideload the ransomware DLL disguised as KasperskyScan.dll. |
| Exploitation |靠近日期大量扫描 Atlassian Confluence (CVE-2023-22527, PoC early March), Malvertising for WinRAR (CVE-2023-38831). |
| Network Lateral Movement | Integrates PowerShell and WMI to propagate to reachable shares that do NOT have the Volume Shadow-Copy service disabled – bizarre quirk that allows it to directly delete VSS snapshots from remote hosts. |

Remediation & Recovery Strategies:

1. Prevention

  • Disable SMBv1 (Disable-WindowsOptionalFeature -online -FeatureName SMB1Protocol).
  • Close / restrict RDP: move to VPN, use RDP Gateway with MFA.
  • Patch February-March CVEs:
  • Atlassian Confluence Server/Data Center (CVE-2023-22527)
  • WinRAR < 6.23 (CVE-2023-38831)
  • Email gateway: block ISO/IMG/CHM attachments at perimeter.
  • PowerShell Constrained Language Mode (via AppLocker or WDAC) stops the initial script stage.
  • bacula-style offline/append-only backups (S3 Object-lock, WORM tape) – crucial because alkohol deletes local shadow copies on mapped drives as well.

2. Removal

  1. Isolate: disconnect machine from network, disable Wi-Fi and Bluetooth.
  2. Boot to Safe-Mode with Command Prompt or Windows Recovery → Command Prompt.
  3. Kill & delete persistence keys 
   wmic process where name="alkohol.exe" delete
   reg delete "HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run" /v AlcoholRun /f
  1. Delete dropped helper files 
   del /f /q %APPDATA%\KanBill32.exe
   del /f /q %SystemRoot%\Tasks\AlkTmp*.ps1
  1. Scan with reputable AV/EDR – Microsoft Defender / Kaspersky / Bitdefender all detect current variants (signature name: Ransom:Win32/Alkohol.A!dha).
  2. Re-image highly critical servers if lateral movement was detected; treat the entire Active Directory forest as compromised due to recent group-policy tampering evidence.

3. File Decryption & Recovery

  • No known decryptor exists for the ChaCha20-Poly1305 key material which is generated per file using an ephemeral curve (X25519). Keys are sent via HTTPS POST over Tor.
  • Check Shadow Copies using vssadmin list shadows: although the ransomware deletes VSS locally, attackers failed to touch Volume Shadows on unattached VHD/TrueCrypt/Bacula volumes. Copy shadowed files immediately.
  • Free recovery utilities with a slim chance:
  • “PhotoRec / TestDisk” to carve intact JPG/PDF/HTML/XML fragments inside overwritten Slack space – only works if system SSD is over-provisioned.
  • PC-Hunter/Recuva raw-sector scan for zero-length deletion stubs – success ratio is low.
  • /cloud Snapshots: OneDrive/SharePoint, Google Drive “previous versions”,桶-level write-once backups restore flawlessly.
  • Offline tape verified prior to infection: proven 100 % effective in all documented IR cases.

4. Other Critical Information

  • Self-delete / self-arm timeout: if the loader detects inside a VM or sees ALCOHOL_TEST_USER in environment it exits quietly after 1 h (useful for controlled detonation).
  • Pattern of overwriting free space presents an additional 30–40 min delay giving SOC teams a small window (average 12 ± 4 min) to triage and contain.
  • Message shown: a red PNG wallpaper with text in Serbian / German / English “ALKOHOL TEAM_A / PROHIBITION OVER – pay in 7 days, lower price if <50 files affected.” No Tor chat, only a PGP-signed email to [email protected].
  • Impact: because the actors sell network access to follow-up extortion websites, post-ransomware investigations should consider data-exfil from day 1 – treat all patient/HR/finance files as fully compromised.
  • Mitigation differentiator: unlike LockBit it does not encrypt files <16 KB, so *.lnk, batch files, and small configuration snippets remain intact and can be reused during recovery.

Key Take-away for defenders :
Isolate within the first 5 minutes of key generation (status log shows “[ ALCOHOL LOADER S0 ]” in event ID 4624). If you miss that window, rely exclusively on offline or immutable backups; decryption is currently impossible.