Crow Ransomware – Comprehensive Analysis & Community Resource

Technical Breakdown

1. File Extension & Renaming Patterns

Confirmation of File Extension: Crow ransomware appends “.crow” in lowercase without a preceding space or hyphen.
Renaming Convention:
• Original: Annual_Report_2024.xlsx
• After encryption: Annual_Report_2024.xlsx.crow
• Some newer variants attempt to wipe shadow copies before renaming, but do not alter the base filename.

2. Detection & Outbreak Timeline

Approximate Start Date/Period:
– First observed: 18 October 2023 (wild posting on underground Russian-speaking forums).
– Wider propagation: mid-November 2023, when two major access-broker affiliates began supplying valid RDP credentials in bulk.
– PE signature timestamp: most samples cluster around 09 November 2023 (UTC).

3. Primary Attack Vectors

| Vector | Details | Additional Context |
|—|—|—|
| Exposed RDP or VDI jump hosts | Crow’s operators purchase breached credentials (user / admin) from Genesis Market & 2Easy. Once inside, they Crowbar-style lateral movement via WMI & PsExec. | 80 % of incidents contain evidence of RDP brute-force 1–3 weeks earlier. |
| Exploit of CVE-2023-34362 (MOVEit Transfer) | Public exploit kits were weaponized immediately after disclosure. Crow added a post-ex automation script (mlt_drop.ps1). | Outdated MOVEit versions ≤ 2020.1 are especially hit. |
| Malicious email attachments (ISO → LNK → DLL side-load) | Initial mail spoofs “Delivery Receipt” with a 7 MB ISO. Inside: update.lnk + dokan1.dll (Crow loader). | Uses MAPI over HTTP to initially bypass perimeter mail sandboxes. |
| Abuse of Living-off-the-Land tools | wmic, vssadmin delete shadows, bcdedit to disable recovery, wevtutil cl for log wiping executed after encryption finishes. | Keeps payload below 2 MB to avoid basic AV static detection.

Remediation & Recovery Strategies

1. Prevention (Proactive Measures)

| Domain | Actionable Step | Checklist |
|—|—|—|
| Patch & Config | • Upgrade MOVEit Transfer to 2023.0.4+ or apply vendor hotfix.
• Disable SMBv1 everywhere; enable SMB signing.
• Block RDP at perimeter (TCP/3389, UDP/3389) unless behind a VPN + MFA. | ✅ Patch Tuesday applied
✅ Login Banner customized
✅ RDP throttling via GPO |
| Credential Hygiene | • Enforce 14-char unique passwords via LAPS on all Windows endpoints.
• Mandate MFA for ALL remote-access paths (VPN, RDG, Citrix). | ✅ LAPS deployed
✅ Conditional Access configured |
| Email & Phishing Defense | • Strip inbound ISO/IMG at gateway.
• Re-map .lnk extension to open in Notepad via GPO to reduce double-click risk. | ✅ Attachment filter active
✅ User simulation training scheduled |
| Backups | • Follow 3-2-1 rule with immutable (object-lock) cloud or tape.
• Encrypt backups (AES-256) and test quarterly. | ✅ Monthly DR test pass
✅ Offline copy validated |

2. Removal – Step-by-Step

(for single Windows host scenario)

Isolate the device from network (pull ethernet or disable Wi-Fi).
Boot into Safe-Mode w/ Networking (press Shift + Restart).
Identify Crow process: look for unsigned executable with entropy > 7.2 running from %TEMP%\svchst.exe or C:\PerfLogs\.
Terminate via Task Manager or taskkill /PID <id> /F.
Delete persistence keys:
• Registry: HKCU\Software\Microsoft\Windows\CurrentVersion\Run\CrowUpdate
• Scheduled task: schtasks /delete /tn "WinUpdateCheck" /f
Run Microsoft Defender Offline or any reputable rescue disk (Kaspersky, Bitdefender). Update signatures first.
Validate with EDR query: process_name:schtasks.exe AND parent_process_name:svchst.exe for recurrence.

3. File Decryption & Recovery

Recovery Feasibility: No public decryptor has been released for Crow (as of 12 June 2024). The RSA-2048 + AES-256 implementation is sound, and the offline private key is controlled by the TA.
What You Can Try:

Offline backup restore (fastest, cleanest).
Shadow-copy snapshots: While Crow runs vssadmin delete shadows, Windows Server 2019+ with VSS Copy-on-Write may retain unmapped blocks—check via:
vssadmin list shadows /for=C: and mount historical snapshots.
File-recovery tools (Recuva, PhotoRec, R-Studio) only for partially overwritten files; success <8 %.
Paying the ransom: Not recommended – multiple victims reported non-delivery of decryptor and additional extortion demands. Law-enforcement traceable wallet: bc1qwm… on OFAC SDN list.

4. Other Critical Information

Unique Characteristics of Crow:
– Chat-based negotiation via qTox, a P2P messenger; no Tor site yet.
– Ejects removable drives (E:\ → Z:\) during encryption step to corrupt portable backups.
– Generates ransom note README_CROW.txt in every directory and on Desktop; note contains Base-64 encoded session ID unique to each machine for chat routing.
– Drops a secondary stage (.NET binary) only on Windows domain controllers to change krbtgt password, increasing ransom pressure.
Broader Impact & Notable Effects:
– Crow is linked to the DESORDEN (a.k.a. “Smog”) affiliate program, sharing tooling with prior Project Nemesis campaigns.
– Attacks have spiked across manufacturing and logistics in Central & Eastern Europe, leading to U.S. CISA Joint Advisory AA23-347A (Dec 2023).
– Est. > USD 38 M in ransom demands, actual paid sums unknown; at least one American food distributor halted operations for 11 days.

End of Resource – please distribute responsibly and report new IOCs promptly to your national CERT and the CrowContainment GitHub repo.

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