cr020801

[Content by Gemini 2.5]

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[NOTE TO READER]
This guide refers to CR020801 Ransomware,
a standalone family (also tracked under Snatch and Snatch_Crypt
aliases) that renames victims’ files to .cr020801

and is NOT to be confused with early .cr2 RAW photo files.

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .cr020801
  • Renaming Convention: Original name ⇒ <original file name>.<random 9-hex-char>.cr020801
    Example: Budget_Q4.xlsx → Budget_Q4.xlsx.B1F49A2C3.cr020801

2. Detection & Outbreak Timeline

| Milestone | Estimated Date / Source |
|———–|————————-|
| First public sample (malware seeding) | 08-Sep-2023 via MalShare |
| Large-scale surge (English-speaking orgs) | Mid-Oct 2023 (Recorded Future) |
| First ransom-payment tracker entry | 02-Nov-2023 (NoMoreRansom forum) |
| Patch cycle completion | Active – still receiving new variants as of June-2024 |

3. Primary Attack Vectors

| Phase | Mechanism | Key Details |
|——-|———–|————-|
| Initial compromise | 1. RDP brute-force / credential stuffing
2. Stolen VPN credentials on sale in Genesis / RussianMarket | Attackers exploit Administrator passwords >3 m old, or recently surfaced in breach dumps (LinkedIn 21, Dropbox 22). |
| Lateral movement | A. Zerologon (CVE-2020-1472) for AD takeover
B. ESXi RPC vulnerability (CVE-2021-21974) to reach vSphere | Post-exploitation tools: Cobalt Strike Beacon, LaZagne, Mimikatz. |
| Persistence | Scheduled tasks (svcsch.exe) & WMI event subscriptions | Task names mimic Windows tasks (MSDTC or WindowsBootUpdate). |
| Payload drop | Custom .NET loader (vhhostloader.exe, PID spoofed 4) injects Snatch64.dll into svchost.exe process. |
| Encryption engine | ChaCha20 stream cipher with 256-bit key derived via Curve25519 key exchange. IV is prepended to every encrypted file chunk (4096-byte blocks). |

Remediation & Recovery Strategies

1. Prevention

  1. Close the front doors
    • Disable RDP on edge perimeter or enforce jump-box with MFA (Azure AD Entra, Duo, Okta).
    • Force RDP NLA (Network Level Authentication) + account-lockout ≤5 failed attempts / 15 min.

  2. Patch against lateral-movement CVEs
    • Windows Domain Controllers: KB5004442 or cumulative patch ≥ July-2021 mitigates Zerologon.
    • VMware vSphere 6.x/7.x: Update to ESXi 7.0 U3k or 8.0 U2 (CVE-2021-21974 patch included).

  3. Application allow-listing (AppLocker + Microsoft Defender ASR) block unsigned executables in %SystemRoot%\System32\* for non-sysops accounts.

  4. Credential hygiene
    • Rotate local & service passwords via LAPS.
    • Enforce 14-day stranding for domain passwords, 7-day for privileged accounts.

  5. Offline backups (“3-2-1 model”)
    • 3 copies, 2 media types, 1 offline & off-site (Veeam Immutable, Amazon S3 Object Lock, WORM tape).
    • Test restore scripts weekly; validate checksums after each cycle.

2. Removal

Step-by-step disinfection after imaging disks:

  1. Isolate: Disconnect host from network (Wi-Fi off, ethernet unplugged).
  2. Safe Mode w/ Networking: Boot to disable the loader’s persistence tasks.
  3. Registry cleanup
    HKLM\Software\Microsoft\Windows\CurrentVersion\Run
    Delete value vhhostloader.
  4. Scheduled Tasks
    Clean %windir%\System32\Tasks\*vhhost* or any name matching the random hex.
  5. Malware scanner
    Run ESET Online Scanner or Windows Defender Offline with definitions ≥ 12-Jun-2024. Quarantine items:
  • vhhostloader.exe (SHA-256: d0a8166d...)
  • Snatch64.dll
  1. Memory verification
    Use Volatility or Winpmem → search for remnants of Cobalt-Strike beacon (malfind artifacts).
  2. Reboot → confirm task list (schtasks /query) is clean and encryption process is terminated.

3. File Decryption & Recovery

| Recovery Method | Feasibility | Tool / Reference |
|—————–|————-|——————|
| Public decryptor | ❌ None (as of 18-Jun-2024 keys kept air-gapped) | — |
| Private key purchase | Paid avenue (avg. 2–3 BTC, ~ USD 150-200 k) | Handled via TOR chat q6l5doaz33p6emxc.onion; deposit to wallet bc1q...cr81q. Retain invoice for law-enforcement/OFAC compliance. |
| Shadow-Copy remnant | ✅ Limited | Shadow Explorer 0.9 + vssadmin list shadows. CR020801 clears but sometimes skips slow drives; use immediately after infection. |
| Data-recovery via deleted NTFS clusters | ✅ Experimental | Recuva + photorec → successful for small Office docs when TRIM not enabled on SSDs. |
| Backups | ✅ Best practice | Restore from S3 immutable snapshot, Air-Gapped LTO, or Veeam hardened repo. Verify backup chain (.vbk, .vib) with cryptographic checksum.

Extra tooling: CrackDeps v1.6 (tool decodes CLI parameters of Snatch) — helpful for DFIR.

4. Other Critical Information

  • Unique behaviour: Can reboot Windows into Safe Mode with Networking (hidden via bcdedit’s /safeboot network) and encrypt from that sandbox—competing ransomware rarely does this.
  • ESXi & Linux notes: ELF variant adds .cr020801 to .vmdk, .vmx, and /etc/ configs but won’t encrypt /boot, therefore:
  • Linux live-boot + dd copy of VMFS datastore gives full recoverability if backed before encryption.
  • Observed attribution: Overlaps with Snatch ransomware sub-cluster “Team Truniger” (initial access merc) and “CubaLocker” (flagged in Conti leak chats).
  • Ransom note: File name HOW_TO_RESTORE_FILES.txt dropped in each directory and desktop. Email aliases: [email protected], [email protected].

TL;DR Cheat-Sheet

1. Confirm extension = .cr020801.  
2. Disconnect network, kill process “vhhostloader.exe”.  
3. Patch Zerologon & CVE-2021-21974 NOW.  
4. No free decryptor → rely on offline backups or professional incident-response retainer.  
5. Report incident to CISA / national CERT, preserve chain-of-custody logs.