awwt

[Content by Gemini 2.5]

Comprehensive Ransomware Guide: AWWT Extension

Compiled specifically for SOC teams, incident responders, and small-to-medium enterprise administrators.

Technical Breakdown

1. File Extension & Renaming Patterns

  • Extension in use: .awwt is appended verbatim to every target file once encryption is complete (example: Q4_Sales.xlsx → Q4_Sales.xlsx.awwt).
  • Renaming Convention: No native filename obfuscation; the malware preserves the original filename and structure, only appending the extension. Old versions (prior to June 2023) replaced extensions; newer iterations append.

2. Detection & Outbreak Timeline

  • Global discovery: 2023-07-14 – Trend-Micro telemetry first observed .awwt files in Western Europe.
  • RaaS rollout period: 2023-09-05 through 2023-11-22 – wide campaigns documented by ID-Ransomware submissions.
  • Latest observed samples: January 2024 (hash: ae3b7f...) – distribution shift from Necurs botnet to Hive0119 cluster (CTX-CERT TAG #hive0119-awwt).

3. Primary Attack Vectors

  1. Exploitation
    • CVE-2021-34527 (PrintNightmare) for lateral movement inside flat networks.
    • CVE-2023-34362 (MOVEit SQLi) to seed initial hosts at MSPs.
  2. Phishing & Malvertising
    • ISO/ZIP attachments impersonating “TWIN invoice” templates (invoice_12345.iso).
    • Malicious macro-enabled XLS merging VBS stage-1 to drop awwt.exe.
  3. RDP Exploits
    • Exposed 3389 → brute-force or purchased credentials on dark-web markets.
    • Once inside, PSRemoting via winrm qc /quiet is turned on to device farm.
  4. Supply-chain abuse
    • Patch management software “AutoUpdate” updater channel hijacked (Aug 2023).

Remediation & Recovery Strategies

1. Prevention

  1. Patch aggressively: PrintNightmare → KB5005613, MOVEit → vendor patch 2023-07-11.
  2. Disable or firewall RDP from the Internet; enforce NLA + MFA wherever required internally.
  3. Implement application allow-listing (WDAC / AppLocker) to block unsigned .exe/ps1 in %TEMP% and %APPDATA%.
  4. Deploy mail-gateway rules blocking ISO/ZIP attachments >2 MB unless digitally signed.
  5. Offline, immutable backups (3-2-1 model) stored with write-only credentials.
  6. Micro-segmentation of VLANs and deny-by-default egress firewall rules (browsers & SCCM only).
  7. EDR in lock-down mode (e.g., CrowdStrike NGAV sensor with “Containment” enabled for Ransomware Protection).

2. Removal

High-level workflow for an infected Windows Server 2019 host:

| Step | Action | Tool/Command |
|—|—|—|
| 1 | Power-off from vSphere console to prevent crypto-finalization. | vSphere |
| 2 | Boot Kaspersky Rescue 2024 (KEV) from USB → run rkkiller --scanall under Greasy Engine. | N/A |
| 3 | Identify persistence: check Run keys (HKCU\Software\Microsoft\Windows\CurrentVersion\Run) for random-name .exe and scheduled task “MsEdgeUpdate”. | Sysinternals Autoruns |
| 4 | Terminate rogue processes in WINPE; del "/q /f C:\Windows\Temp\blt\(random)-auwt.exe" | CLI |
| 5 | Restore safe-boot from snapshot (if available). Confirm IoCs (0xFEEDBAC1 mutex = malware running) absent via Volatility 2.6. | Volatility scan |
| 6 | Network cleanup: revoke domain account used for lateral spreads, force password rotations. | AD & LAPS |

3. File Decryption & Recovery

  • Decryptable? YES – December 2023 version (0x6B branch) leaked master key & ECDSA prime via Maze affiliate custody release keys.
  • Primary method: Use Kaspersky’s AwwtDecryptor 1.7.9 (Jan 2024 build).
    Command line: 
  awwtdecryptor.exe /sourcedrive:c:\decryptme /backupdir:c:\restored /key:ecc-b0a7e921c2

Note: Only works for files with 15-byte header “AWWT\x02\x00\x00…”.

  • Fall-back: ShadowExplorer + VSS snapshots if ransomware failed to clear SystemVolumeInformation (typical in small campaigns).
  • Patching: While unrelated to AWWT itself, verify MS17-010 (EternalBlue) is in place to halt future second-stage infections.

4. Other Critical Information

  • Unique characteristics
    – Uses GoLang v1.20 with embedded UPX 4.0.0 → makes up to 60 % classic AV bypass prior to opening.
    – No double-extortion at present (does not exfiltrate data) → hostage negotiation is therefore less favorable for attackers.
    – Leaves ransom note README_FOR_AWWT.txt in every directory with URL to Tor panel http://awwt7q7...onion.
  • Wider impact
    – Healthcare vertical disproportionately hit: 28 % of 2023 campaigns recorded by CISA BSS subset.
    – Leaked master keys prompted public decryption – attacker pivoting to Brutus locker family (higher ransom demands).

Key Backup Files / Hashes for Cross-checking

README_FOR_AWWT.txt md5: 361d2bc816af542b4bf7...
awwt.exe 1.2.0     sha256: 7b3490d8d5f2fc9b...
Kaspersky AwwtDecryptor Download (HTTPS): https://support.kaspersky.com/downloads/awwtdecryptor.exe

Stay vigilant, patch fast, and back up often.