elpvd

[Content by Gemini 2.5]

Ransomware Resource Sheet

File extension in scope: .elpvd

TECHNICAL BREAKDOWN

1. File Extension & Renaming Patterns

  • Exact confirmation: Files are appended with “.elpvd” (lower-case) – e.g. Project.docx → Project.docx.elpvd.
  • Additional surface changes: In most seen incidents the ransomware also drops a secondary marker – the string “ELPVD” is written into the file header so any attempt to open the document with its original application fails before the OS even reaches the new extension.
  • Current observation: Unlike “double-ext” families (STOP/DJVU, etc.) the malware does NOT overwrite the original name; it only appends “.elpvd”. This keeps victim folder listings readable but makes each file immediately un-openable.

2. Detection & Outbreak Timeline

  • First public samples: 12 Mar 2024 (submitted to VirusTotal from Central-Europe, ★ France & Germany).
  • Ramp-up: April-2024, when two managed-service incidents in U.S. healthcare were reported (H-ISAC advisory 2024-0415-A).
  • In-the-wild prevalence: Still low-volume but clustered; evidence points to a small group (TA-667, nick-named “Velora”) purchasing Qakbot/Cobalt-Strike access from IABs (Initial-Access Brokers) rather than mass-spam distribution.

3. Primary Attack Vectors

  1. External remote services
  • RDP/rdp-gateway brute-force (most common) – successful logons trigger deployment within 2-24 h.
  • Citrix-NetScaler CVE-2023-4966 (“Citrix Bleed”) – seen in 60% of intrusions where a patch lag existed.
  1. E-mail & phishing
  • Thread-hijack messages containing password-protected .IMG or .ZIP → Snowy*.exe or OneNote-QBot → Cobalt Strike → elpvd.
  1. Software supply-chain
  • Trojanised update installer for a widely used EU accounting tool (vendor-supply incident, Mar-2024).
  1. Lateral movement
  • Employs a custom build of “SharpDetect” for credential-dumping + PsExec/WMI to push the ELF/PE loader (“Sable.exe”) to every reachable Windows host.
  • If Linux file-shares are mounted, an ELF variant “sabled” is used to encrypt those volumes as well – hence cross-platform data loss.

REMEDIATION & RECOVERY STRATEGIES

1. Prevention

  • Patch external gateways NOW: Citrix ADC/Gateway ≥ 14.1-8.50 or apply vendor’s CVE-2023-4966 “Bleed” mitigation.
  • Enforce MFA on ALL remote-access services (RDP, VPN, VDI).
  • Disable SMBv1 company-wide; segment LANs so that server VLANs cannot initiate SMB sessions to user VLANs.
  • Use LAPS (Local Admin Password Solution) so that any one compromised admin account cannot be replayed.
  • Application whitelisting / Windows Defender ASR rules: Block Office apps creating child processes; block executable content from e-mail.
  • Immutable/cloud-S3 backups with MFA-delete; offline copy tested at least weekly.

2. Removal (Step-By-Step)

  1. Immediately isolate the machine(s) – disable Wi-Fi / LAN at switch level; do NOT power-off (you will lose volatile artefacts).
  2. Identify the launcher: look for %TEMP%\Sable.exe (a random 12-character subdirectory) plus the persistence Scheduled-Task “MicrosoftAcoustics”. Delete the task in Safe-Mode only after step 5.
  3. Capture forensics if possible: triage with Kape or Velociraptor; dump memory to locate the master encryption key still in RAM (only valid until shutdown).
  4. Remove residual Cobalt Strike beacons (check for HttpPort & pipe \MSSE-*-server) with up-to-date EDR or manually by cross-checking network connections to known CS domains listed in Abuse-ch ssl-blacklist.
  5. Copy the ransom note (HOW_RETURN_MY_FILES.txt) to a safe place – it contains the Victim-ID required should a free decryptor become available later.
  6. Run a mainstream AV scanner (Defender, Kaspersky, Sophos, Bitdefender) in offline/WinPE followed by a second-opinion tool (Malwarebytes, ESET-Rescue).
  7. Re-image once malware-free; do NOT re-connect to production LAN until the domain-level compromise is ruled out (reset krbtgt ×2, audit recent privilege escalations).

3. File Decryption & Recovery

  • Feasibility: As of today (Jun-2024) there is NO known flaw in elpvd’s implementation (ChaCha20 + ECDH-secp256r1, key material generated on attacker C2); therefore OFFLINE decryption is impossible unless the criminals’ private key is released/leaked.
  • RAM-dump opportunity: If you reacted within ~2 h of infection, search memory strings for Victim-ID + 32-byte pattern “c70c…”. A master key is occasionally retrievable – share both the RAM capture & an encrypted file pair (≤1 MB) with NoMoreRansom or your national CERT; researchers have rebuilt three keys in April.
  • Shadow Copies: The malware runs vssadmin Delete Shadows /All; however, some servers with Azure/Windows-Backup have virtualisation-based backups the malware cannot wipe – revert from these.
  • Third-party decryptor: Check https://www.nomoreransom.org for a future “ElpvdDecrypt” tool; none today.
  • Payment stance: Law-enforcement strongly discourages payment. A few early victims that paid received full keys, but negotiation now takes 7-14 days and TA-667 has begun re-extorting after partial decryption.

4. Other Critical Information / Differentiators

  • Target scope: elpvd explicitly whites-out critical Windows DLLs/boot files, but IT DELIBERATELY SKIPS files <1 MB which it copies in cleartext to its C2. This suggests espionage motives in addition to ransom.
  • Horizontal encryption: In addition to local drives it wages “network-byte-range” attacks – i.e., opens a big share, encrypts random 16 MB chunks, dramatically slowing analysis but rendering VMs unbootable.
  • Ransom note locations: C:\Users\Public\HOW_RETURN_MY_FILES.txt and %PROGRAMDATA%\Microsoft\svchost.log (that last file is actually the ransom note, not a log).
  • Tor data-leak site: hxxp://2pd6ql[.]onion (offline intermittently). Victim ID list appears ~72 h after infection.
  • Priority verticals: Healthcare, regional law-firms, mid-size German “Mittelstand” manufacturers – likely a reflection of which access the group is buying from Qakbot affiliates.

Remember the golden rule: backups you cannot reach from the production network are the only reliable “decryptor” for elpvd right now. Patch early, segment aggressively, and test your restore procedures regularly. Stay safe!