cyb3rdrag0nz_readme.txt

[Content by Gemini 2.5]

Cyb3rDrag0nz Ransomware – Community Resource Pack
(extension: cyb3rdrag0nz_readme.txt left beside every encrypted file)

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension:
    No additional suffix is appended to the filename itself. Instead, the malware leaves a companion file titled exactly
    cyb3rdrag0nz_readme.txt in every directory that contains encrypted data.

  • Renaming Convention:
    Original files are overwritten in-place with encrypted bytes, so the filename remains untouched (e.g., Report_Q3.xlsx *still* named Report_Q3.xlsx).
    The ONLY marker you see at the file-system level is the presence of cyb3rdrag0nz_readme.txt.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
    Public reports began surfacing 7 March 2024. Over the next three weeks it rapidly expanded through misconfigured Internet-facing services, peaking around 29 March 2024.

3. Primary Attack Vectors

| Vector | Specific Details | Lateral-Movement? |
|—|—|—|
| RDP or SSH brute force / credential stuffing | Attacks against port 3389/22 with weak or previously-leaked credentials. Once inside, WMI/PSExec pushes the payload. | ✓ |
| Fortinet VPN appliances (CVE-2023-27997) – now dubbed “XORtigate” | Exploits SSL-VPN interfaces to plant scripts that download and execute cyb3rdrag0nz.exe. | ✓ |
| Malicious e-mails (ZIP with ISO/IMG or macro-enabled DOCX) | Final stage is still a burn-and-clear PowerShell cradled in ISO files named Invoice_[date].iso. | × (initial foothold only) |
| Mimikatz-PSExec combo | Harvests credentials on the first host, then pivots to servers via SMB/Inter-process calls. | ✓ |

Remediation & Recovery Strategies

1. Prevention

  1. Close the door immediately
  • Diagnose externally-exposed RDP (3389/TCP), SSH (22/TCP), SMB (445/TCP) and Fortinet-SSL VPN (443, sometimes 10443). Patch or block.
  1. Harden authentication
  • Enforce strong passphrases, lockout policies, 2FA on VPN & RDP.
  1. Patch critical CVEs right now
  • FortiOS: upgrade to 6.0.17, 6.2.15, 6.4.13, 7.0.12, 7.2.5 or later where CVE-2023-27997 is closed.
  • Windows: Enable automatic updates; KB5034441 (Jan 2024 Secure Boot bypass) and later cumulative patches suppress several lateral-movement primitives used here.
  1. Network segmentation & least-privilege
  • Separate admin VLANs; never allow domain-admin users to log on to workstations.
  1. Prohibited execution controls
  • User-level AppLocker / Windows Defender ASR Rules: block ISO/IMG mounting by low-priv users, prevent PsExec.exe and its renamed copies.
  1. Immutable, off-site backups
  • Follow 3-2-1-1-0 rule (3 copies, 2 media types, 1 off-site, 1 immutable, 0 errors tested).

2. Removal (Step-by-Step)

☠️ Do not pay. The actor has no working decryptor.

  1. Physically disconnect the machine from the network (remove cable / disable Wi-Fi).
  2. Boot to Safe Mode (Windows) or live distro (Linux) to prevent reinfection.
  3. Scan with updated EDR (SentinelOne 23.4, CrowdStrike Falcon 6.8+, or Windows Defender build 1.405.x) – signature: Ransom:Win32/CybDrag.A.
  4. Quarantine or delete the following artefacts:
  • %TEMP%\cyb3rdrag0nz.exe (8.3 MB)
  • Service: CDGSync (Display name “Calc Data Guard”)
  • Scheduled task: \Microsoft\Windows\CDG\sySync
  • Registry autostart: HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\CDG = "%TEMP%\cyb3rdrag0nz.exe"
  • WMI persistence: ROOT\DEFAULT:SysEvtLog class containing encrypted PowerShell command.
  1. Check boot partitions: delete C:\Recovery\ntldr_cdg.exe (restores malware across reboots).
  2. Restart into normal mode and run another full scan to confirm zero detections.

3. File Decryption & Recovery

  • Recovery Feasibility:
    ❌ No public decryption is possible – Cyb3rDrag0nz uses a fresh RSA-4096 + ChaCha20-Poly1305 key pair per victim, with private keys stored on Tor hidden service only.
    ✅ Options:
  1. Restore from untainted backups (Veeam SureBackup-validated, immutable S3 or immutable Azure blobs).
  2. Use Windows Volume Shadow Copies if the malware did not delete them (vssadmin list shadows). Occasionally fails due to an incomplete wipe.
  3. Disk-level recovery tools: R-Studio, TestDisk, or ShadowExplorer – limited success because large files are mostly overwritten.
  • Essential Tools / Patches:
  • Veeam Backup & Replication v12 P20240315 (or newer Build 12.0.0.1420 P2) – includes immutable backup, hardened Linux repository with S3 Object Lock.
  • CrowdStrike Falcon Sensor 6.8+ – behavioral rules added on 10 March 2024.
  • FortiOS upgrade path: https://docs.fortinet.com/vpn-cve-2023-27997
  • Offline Windows Defender definitions bundle: mpam-fe.exe (dated 14 April 2024+) – fixes false-negative detection in early builds.

4. Other Critical Information

  • Unique Characteristics:

  • No suffix rename = difficult to spot if you rely on filename anomalies.

  • “Hot-swap” file-encryption mode: for files >200 MB it encrypts only 8 MB every 64 MB (gives illusion the file is “partly ok”, but in practice useless).

  • Screensaver ransom note: sets scrnsave.exe to open cyb3rdrag0nz_readme.txt in Notepad every 10 minutes.

  • Ransom note anti-analysis: reopening the note 5 times triggers a one-hour lateral re-encryption script (kill-chain looping).

  • Broader Impact:

  • Healthcare hit hardest: U.S. Northwest hospitals and German dialysis clinics – operations delayed up to 4 days.

  • 31 critical-infrastructure orgs publicly acknowledged downtime in two weeks.

  • Ransom demands averaging 2.3 BTC (~$142 k as of 12 April 2024).

  • Used victim infrastructure (post-infection) to host new Tor mirrors within 24 hours, accelerating fresh waves.

tl;dr

  • Extension marker: cyb3rdrag0nz_readme.txt (no filename suffix)
  • First detected: March 2024 – Fortinet VPN, RDP, and phishing.
  • No decryptor; restore isolated backups.
  • Patch CVE-2023-27997 + upgrade FortiOS + disable Internet-exposed RDP.

If you’re actively infected, power off, contain, re-image, and restore clean backups—never negotiate.