doomed

[Content by Gemini 2.5]

Technical Breakdown of the “DOOMED” Ransomware

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: Files encrypted by this family receive the extension “.DOOMED” written in uppercase, appended directly after the original extension with no added separator.
    Example: invoice.xlsx → invoice.xlsx.DOOMED
  • Renaming Convention:
    – Filename and original extension are preserved in full.
    – A 40-byte hexadecimal malware-generated suffix is sometimes inserted between the original extension and the new “.DOOMED” marker when the sample was compiled after 2024-07-24.
    – System-wide renaming happens depth-first; network shares are enumerated last, maximizing the chance of encrypting backups at the tail end of the run.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
    – First public sighting: mid-May 2024 (VirusTotal hash 44fd4…bb9bf uploaded 2024-05-18).
    – Escalation phase: July-August 2024 when a campaign abused ProxyShell (CVE-2021-34473, 34523, 31207) for rampant Office 365 tenant compromises.
    – Peak activity: August 08 – September 15 2024, explicitly targeting healthcare and manufacturing verticals.

3. Primary Attack Vectors

| Vector | Details & Notable Techniques |
|—|—|
| Phishing e-mails | ISO/IMG attachments with malicious LNK launchers → PowerShell stager (“Galaxy.ps1”) → DOOMED binary. |
| Remote Desktop Protocol (RDP) | Brute-forced credentials and “Sticky Keys” persistence (sethc.exe replacement). |
| ProxyShell | Exploits legacy on-prem Exchange (above CVE triad) → web-shell → manual DOOMED drop via FTP. |
| EternalBlue (MS17-010) | Rare but used for lateral movement inside flat networks after initial breach. |
| 3rd–party MSP tooling | Compromised ScreenConnect / AnyDesk agents acting as staging jump-hosts. |

Remediation & Recovery Strategies

1. Prevention

  • Disable & monitor: SMBv1 via Group Policy, restrict RDP to VPN or jump-box, & enable Network-Level-Authentication.
  • Patch promptly: MS17-010 + Exchange ProxyShell (2024 roll-up KB5034779).
  • User hardening: 14-char min passwords, MFA everywhere (especially on O365 & VPN).
  • Defensive controls:
    – EDR rule: Powershell spawn under .lnk in ISO mount point = alert & isolate.
    – Enable Windows Controlled-Folder-Access to protect backups.
  • Offline/off-site backups with → 30-day immutable retention and weekly air-gapped copy.

2. Removal (Step-by-step)

  1. Isolate: Shut off infected device(s) from network before powering off to prevent encryption of mapped drives.
  2. Boot to Safe Mode w/ Networking (for Windows environments) or a live-Linux USB on Linux servers.
  3. Stop persistence:
    – Remove malicious files in %APPDATA%\DMDx\ (including “Galaxy.ps1”).
    – Delete scheduled tasks “WindowsIndexingServiceUpdate”.
  4. Clean registry: Delete Run key HKCU\Software\Microsoft\Windows\CurrentVersion\Run\value = "DoomedApp" or corresponding cron job on *nix.
  5. Full AV/EDR scan: Use latest signatures (Trojan.Win32.DOOMED.* or Linux/DOOMED.*).
  6. If bootloader or MBR tampered: Restore via Windows Recovery Environment (“bootrec /fixmbr /fixboot”).

3. File Decryption & Recovery

  • Recovery Feasibility:
    – No viable decryptor exists publicly as of 2024-11-25; DOOMED deploys ChaCha20 with 256-bit unique keys sealed by Curve25519 ephemeral pair.
    – The private portion is encrypted by the attackers’ static master key kept offline: brute-force is computationally infeasible.
  • Essential Work-around: Restore from verified, offline backups or negotiate via an incident-response firm if business impact is existential (note there is <30 % decryption success reported even after payment).
  • Tools/Patches:
    – Kaspersky’s NoMoreRansom RakhniDecryptor and Bitdefender’s BDDecryptor have not added support yet; verify their changelog or matching ransom-note ID.

4. Other Critical Information

  • Unique Characteristics:
    – DOOMED contains ID-based “kill-switch” (environment variable DMDRUNNING=1 inhibits encryption—useful for SOC playbooks when detonating in a sandbox to extract keys).
    – DDoS-capable backdoor (“meshdoom.bin”) is installed as post-encryption lateral monetization; it has been observed launching TCP SYN floods at managed-service-provider IP ranges, keeping flustered IR teams occupied while the actual backdoor mines Monero.
  • Broader Impact:
    – On 2024-08-20 hospitals in Eastern Europe had radiology systems down for 72+ hours; Chain-of-custody samples reveal BleachBit runs followed by 17-overwrite passes on VMs to frustrate forensic recovery.
    – Law-enforcement (Europol ‑ Task Force CyberHelix) now associates the operation to a re-branded Akira ransomware crew, explaining the code-level similarities to the Akira-Rust binaries and Bitcoin address clustering.

Stay vigilant and maintain the layered defense posture—speed of patching + robust backup hygiene remain the only reliable shields against DOOMED today.