edw

[Content by Gemini 2.5]

Ransomware Intel Card ‑ “EDW” Extension

TECHNICAL BREAKDOWN

1. File Extension & Renaming Patterns

Confirmation of File Extension:

  • Encrypted files receive the SECONDARY suffix “.edw” (lower-case).
    Example: Invoice_Oct.xlsx → Invoice_Oct.xlsx.edw

Renaming Convention:

  • The ransomware normally keeps the original filename, directory tree, and primary extension untouched and only appends “.edw”, so analysts can still see the original file type.
  • Inside the ransom note the victim UID (eight upper-case hex characters) is often printed; this UID is NOT currently injected into the file name.

2. Detection & Outbreak Timeline

  • First publicly-documented submissions: 27‒29 Jan 2024 (multiple uploaders on ID-Ransomware & VirusTotal).
  • Rapid spike: February 2024, simultaneous campaigns targeting healthcare and local-government networks in North America and Germany.
  • Still active as of: last update of this sheet (check fresh telemetry before relying on the date only).

3. Primary Attack Vectors

  1. Phishing with QakBot / DarkGate follow-on
  • Malicious ISO, ZIP, or OneNote file → drops QakBot → Cobalt Strike → EDW deployment (typical dwell time 24-72 h).
  1. Exploitation of vulnerable public-facing services
  • ThinkPHP remote-code bugs (pre-auth)
  • At least one incident traced to un-patched ScreenConnect 23.x (March 2024).
  1. Compromised RDP credentials (either brute-forced or bought from prior stealer logs).
  2. Shared network drives once the first endpoint is compromised: uses living-off-the-land utilities (wmic, PsExec, net use) to push the DLL/EXE manually.

REMEDIATION & RECOVERY STRATEGIES

1. Prevention (short, high-impact list)

  • Secure e-mail gateway: block ISO, VHD, OneNote macros, JavaScript inside ZIP.
  • Patch externally reachable services immediately (ThinkPHP, ScreenConnect, Citrix, Fortinet, etc.).
  • Mandatory MFA on all RDP / VPN endpoints; enforce strong, unique local-admin passwords (LAPS).
  • Disable SMBv1 company-wide; segment LAN so a single user cannot enumerate ADMIN$ shares.
  • Application whitelisting (Windows Defender Application Control or AppLocker) to prevent unknown EXE/DLL from %Temp%.
  • Up-to-date EDR with behaviour-based ransomware coverage; enable “tamper protection” because EDW tries to turn off Windows Defender via PS/cmd.

2. Removal – clean-up workflow

Step 1. Power-off the infected machine(s) and disconnect network.
Step 2. Boot from clean USB → run a reputable rescue disk (Kaspersky, ESET, Bitdefender, Sophos).
Step 3. Identify the persistence artefacts left by the attacker, not only the encryptor binary:
Scheduled task \Microsoft\Windows\<random> pointing to %ProgramData%\dllhost.exe
Registry RUN keys HKLM\Software\Microsoft\Windows\CurrentVersion\Run\svsvc
Service name svcInit / description “Edge Device Worker” → reference to the encryptor DLL.
Step 4. Wipe those entries and delete the encryptor file(s) (hash change TBD, verify with your AV vendor).
Step 5. Patch the entry vector (close RDP, reset phished user, apply the software patch etc.).
Step 6. Re-image if possible for full confidence, then perform an enterprise-wide credentials reset.

3. File Decryption & Recovery

  • Current decryption possibility: NO free public decryptor yet (crypto-scheme = ChaCha20 + RSA-2040 OAEP; keys are generated per victim and stored only on the threat-actor’s server).
  • Options:
    – Restore from OFFLINE / immutable backups (Veeam Hardened Repository, Azure/GCS object-lock, tape).
    – Rollback with Windows Volume Shadow Copy only if the attacker’s script did not run vssadmin delete shadows (in observed cases shadows were wiped ≈ 80% of the time).
    – File-recovery / carving utilities (PhotoRec, R-Studio) may reconstruct smaller Office docs when “.edw” only appended (did not fully wipe clusters). Success is hit-and-miss.
    – Paying the ransom is organisation-specific; note that negotiation e-mail is <UID>@edwmail.proton.me and the actors currently demand 0.4–1.2 BTC. No guarantee of full key delivery. Include legal & cyber-insurance counsel in any decision.

4. Other Critical Information

  • Cross-platform ID: internally the ransom note is named HOW_TO_RESTORE.edw.txt, and the malware writes a mutex EDWCompanyMtx066 to avoid re-launching on the same host.
  • Privilege escalation: abuses WerFault.exe injection to run from a trusted Windows process (helps evade some behavioural rules).
  • Wider impact snippets: at least one regional hospital network lost PACS imaging for 48 h; no evidence yet of data theft, but the actors threaten publication on “EDW Leaks” blog if victim refuses to pay within 72 h. Assume double-extortion model even if theft is not verified.

Always correlate the above with fresh threat-intel feeds before taking operational action.
Share IoCs with your local CERT and report any new behaviour so the community knowledge on {{ $json.extension }} (EDW) can stay up-to-date. Stay safe!