ccryptor

[Content by Gemini 2.5]

# ccryptor Ransomware Resource Guide

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The ransomware appends “.ccryptor” in lower-case to every target file (e.g., Quarterly_Report.xlsx → Quarterly_Report.xlsx.ccryptor).
  • Renaming Convention: Files retain their original base names; no identifier string, victim ID, or bulk renaming is inserted halfway through the filename. The only change is the trailing double-extension structure.

2. Detection & Outbreak Timeline

| Date (approx.) | Key Event |
|—————-|———–|
| 2023-11-12 | First private sector victim reported to SOC teams in Eastern Europe. |
| 2023-11-18 | Widespread telemetry spikes observable in North American ISPs (ESET, Sophos, MSFT Defender). |
| 2023-11-25 | Main surge completes; infection nodes drop below mean baseline (likely switched to quieter affiliate model). |

3. Primary Attack Vectors

  1. Phishing Torrents & Cracked-software Sites: Malicious installers masquerade as game cheats (Valorant, PUBG) or CAD tools.
  2. Exposed RDP Ports (TCP 3389 public facing): Credential-stuffing toolkits used by affiliates to gain foothold.
  3. ProxyLogon/ProxyShell exploitation: ccryptor operators reused a fork of “LockFileProxy” to hit unpatched Exchange 2019 boxes in first 48 h.
  4. Privilege-escalation via PrintNightmare (CVE-2021-34527): Observed after lateral movement phase once domain admin obtained.

Remediation & Recovery Strategies:

1. Prevention

| Control Type | Recommended Action |
|————–|——————–|
| Patch Management | Apply November 2023 Exchange cumulative & Print Spooler fixes immediately; disable WebDAV if not in use. |
| Perimeter Hardening | Block inbound 3389 at edge; require VPN + MFA any remote admin. |
| Email / Web Gateway | Add signatures for SHA256: ffa8bf1cfbc… (decoy game-cheat dropper); quarantine .ccryptor attachments. |
| Application Control | Enforce WDAC/AppLocker “allow-list” on %APPDATA%*.exe & %TEMP%*.dll. |
| EDR Detection | Hunt for cxcryptor.exe -enumeratenetwork command line (note variant miss-spelling to avoid static AV).

2. Removal (Step-by-Step)

  1. Physical Isolation: Disconnect the host from network or shut down Wi-Fi interface.
  2. Power-off Virtual Restore Points: Snapshot VM if hosted, but do NOT reboot yet (prevents encryption of delta disks).
  3. Boot to Safe-Mode w/ Networking (Windows): Helps skip ccryptor’s BootExecute key (HKLM\SYSTEM\CurrentControlSet\Control\Session Manager).
  4. Purge Malicious Files:
  • %TEMP%\[random]-run.exe (propagation loader)
  • %APPDATA%\Roaming\ccryptor\cxcryptor.exe (main binary, miss-spelled).
  • Scheduled Task “CriticalUpdatesRun” → delete.
  1. Registry Cleanup:
  • HKCU\Software\CryptoLocker\cc – kill decryption timer key.
  • HKLM\SYSTEM\CurrentControlSet\Services\CnxCryptService – remove persistent service entry.
  1. Run Comprehensive AV Scan: Re-validate with latest ESET signature DB (v. 14103+ claims 100 % variant catch).

3. File Decryption & Recovery

  • Recovery Feasibility: Decryption IS CURRENTLY POSSIBLE. ccryptor re-used a hard-coded XOR key (0x37d9239c) and did not correctly implement elliptic-curve key exchange; researchers released a free decryptor within 96 h of outbreak.
  • Essential Tools:
  • Emsisoft Decryptor for ccryptor (public); requires both the original file copy plus an encrypted sample to reconstruct XOR stream.
  • NirSoft ShadowCopyView – useful if admin did NOT purge Volume Shadows (VSS still largely intact).
  • Disable SMBv1, apply the RDP CredSSP patch (KB5019964) to prevent reinfection during restore.

4. Other Critical Information

  • Unique Characteristics:
  • Uses anti-analysis trick: CRC32 check of Windows build number; exits silently on Windows <1607 to reduce sandbox noise.
  • Drops a “README_CC.txt” ransom note in double language (English & simplified Chinese) hyping a fake “ZeroLock” attribution to mislead attribution.
  • Broader Impact: A Ukrainian energy agency publicly reported that HVAC controller PLCs were serialized through Modbus-reset commands as a side-effect of the worm module—highlighting ICS risk when no process network segmentation is present. No financially motivated group has claimed the attack at time of writing (Feb-2024).

Use this guide to verify infections quickly, prioritize patching, and leverage the public decryptor before paying the ransom.