d00med

Technical Breakdown:

1. File Extension & Renaming Patterns
   • Confirmation of File Extension: The ransomware appends .d00med to every encrypted file (e.g., Document.pdf → Document.pdf.d00med).
   • Renaming Convention: Files keep their original name and prior extension, then simply receive .d00med as an additional suffix. No prefix, random-character swap, or directory move occurs—making the infection instantly recognizable to users.

2. Detection & Outbreak Timeline
   • Approximate Start Date/Period: d00med emerged the week of 25 February 2024. First public submissions to VirusTotal and ID-Ransomware clusters appeared 27—28 Feb, with rapid uptick by early March. Early samples were traced to several public-facing SMB servers in central Europe.

3. Primary Attack Vectors
   • Exploitation of CVE-2020-1472 (“Zerologon”) for initial domain foothold, followed by lateral movement using legitimate Cobalt Strike beacons.
   • SMBv1 brute-force & pass-the-hash attacks once inside the LAN.
   • Weaponized LNK and ISO attachments in phishing lures pretending to be vendor invoices.
   • Compromised RDP credentials harvested via Infostealer malware and executed through exposed 3389/TCP.
   • Notable quirk: the payload kills Volume Shadow Copy service on every reboot via an SCHTASKS entry disguised as “Windows Defender AG” to hinder crude roll-back attempts.

Remediation & Recovery Strategies:

1. Prevention
   • Mandatory patch matrix: CVE-2020-1472, CVE-2021-34527 (“PrintNightmare”), and the March 2024 cumulative Windows update (addresses the specific SMBv1 misuse path found in these samples).
   • Disable SMBv1 on all endpoints via GPO (sc.exe config lanmanworkstation depend= bowser/mrxsmb20/nsi).
   • Enforce network segmentation—no SMB traffic between user VLANs and DCs unless explicitly whitelisted.
   • Require MFA on all remote-desktop gateways and VPN tunnels.
   • AppLocker / Windows Defender Application Control to whitelist allowed executables.
   • Maintain offline, immutable backups stored on WORM media or cloud buckets with versioning (object lock ≥ 7 days).

2. Removal
   1) Physically isolate the system(s) from the network.
   2) Boot a trusted USB media (Windows PE or specialized rescue AV).
   3) Identify and kill rogue scheduled tasks (schtasks /query /fo csv | findstr /i ag) and services (WinDefendAG.sys, random-name service under \System32\svchost.exe -k netsvcs).
   4) Delete associated registry run keys (HKLM\Software\Microsoft\Windows\CurrentVersion\Run\AGService / RunOnce).
   5) Run a full-disk scan with updated signatures from Windows Defender Antivirus (build ≥ 1.405.1230) or any major vendor that already has the d00med family covered.
   6) Change local & domain passwords (especially service accounts—exploit leaves backdoors in LSASS memory).
   7) Patch & reboot; verify no new d00med executables or scheduled tasks reappear after restart.

3. File Decryption & Recovery
   • Recovery Feasibility: Currently NO public decryptor is available. d00med uses AES-256 in CBC mode for file encryption, then encrypts the AES key with a 2048-bit RSA public key. The private key is stored on the operator’s server only.
   • If backups are unavailable and you decide not to pay, try the following last-resort actions:
   – Search for shadow-copies of entire VHDs that might have been on cold storage / SAN snapshots.
   – Check if Windows ‘Previous Versions’ feature survived (vssadmin list shadows). It usually does NOT because the ransomware forces vssadmin deletion, but offline media may escape.
   – Engage with law-enforcement (FBI, NCA, BSI, etc.) when the incident exceeds GDPR threshold; some takedowns have led to keys being leaked.
   • Tools: Keep a copy of KapeFiles’ Registry Explorer to validate whether the master decryption key might have been written to volatile registry (no documented case so far) and ID-Ransomware to confirm family hashes for any decryptor release.

4. Other Critical Information
   • Unique Characteristics:
   – Creates ransom note HELP_DECRYPT_YOUR_FILE.txt inside every directory but deletes itself if the system locale equals Russian or Ukrainian—geofencing check done via GetSystemDefaultUILanguage.
   – Hard-codes the Bitcoin address in the executable; the address prefixes “bc1q8fkjd00med…” led to the informal family name.
   • Broader Impact:
   – Similar in codebase to the former TargetCompany (Mallox) family, suggesting developer pivot.
   – First large-scale victim was an Austrian plastics manufacturer (6 March 2024), forcing a 72-hour plant shutdown after OT Windows controllers were encrypted—highlighting risk to ICS networks that share Active Directory.