el polocker

[Content by Gemini 2.5]

elopolocker Ransomware – Community Defense & Recovery Guide

Disclaimer: This advisory is compiled from publicly reported artefacts, incident-response notes, and reverse-engineering publications available up to June 2024. IOCs (indicators of compromise) are supplied “as-is” for triage only—always validate in your own environment.

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmed extension added to every encrypted object: .elopolocker
    (e.g. Invoice_DEC2023.xlsx ➔ Invoice_DEC2023.xlsx.elopolocker)
  • Renaming convention:
  • Appends the single new extension immediately after the original one (no e-mail address, no random ID, no underscore separator).
  • Files already bearing double extensions keep the chain, so photo.jpg.bak becomes photo.jpg.bak.elopolocker.
  • Directory-wide marker: drops HOW_TO_RECOVER_FILES.txt (sometimes README_TO_RESTORE.txt) into every folder visited.

2. Detection & Outbreak Timeline

  • First publicly documented submissions: 19-Jan-2024 on ID-Ransomware & VirusTotal (tag “elopolocker”).
  • Sharp uptick reported: late-March 2024 (multiple Latin-American health-sector alerts) and again in May 2024 (European MSP break-ins).
  • Active clusters: still observed as of June 2024; no signs of voluntary shutdown or law-enforcement takedown.

3. Primary Attack Vectors

  1. Phishing with ISO/IMG lures – messages impersonating Spanish courier and Chilean tax agency; archives contain an .ISO mounting to an .LNK launcher.
  2. SMB-brute & RDP exploits – leverages the familiar combo of:
  • External RDP open on TCP/3389, weak/cracked credentials, or
  • Reverse-SOCKS tunnel planted by an earlier commodity loader (SocGholish, Matanbuchus).
  1. ProxyLogon (MS Exchange) – post-proxy shells used to deploy remote-access tools, then elopolocker weeks later.
  2. Confluence CVE-2023-22515 – one MSP case notes ransomware execution two hours after OGNL injection.
  3. Lateral movement – uses renamed PsExec plus WMI to push elop.exe (main payload). Drops a repackaged, silently installing RustDesk or Atera to maintain persistence while encryption runs.

Remediation & Recovery Strategies

1. Prevention – Reduce Attack Surface Now

  • Remove/disable SMBv1 company-wide (MS17-010 patch roll-up).
  • Block TCP/3389, 445, 135 at perimeter; require VPN+2FA for any remote admin console.
  • Enforce LAPS (local-admin password solution) + robust 14-20-char service-account passwords.
  • E-mail-gateway rules: strip ISO, IMG, VHD, . OneNote, .HTA, .JS from external mail by default.
  • Windows AMSI-capable AV (Defender, CrowdStrike, Sophos, etc.) with cloud-lookback ON; enable “Block on Locky-Like extension spam” heuristic if offered.
  • Tiered backups: offline, immutable, tested. Follow 3-2-1-1-0 (three copies, two media, one off-site, one offline, zero backup-verification errors).

2. Removal – Cleaning an Active Infection

  1. Power & network isolation – pull RJ-45/Wi-Fi, disable Wi-Fi adapter, shut down lateral shares.
  2. Identify patient-zero – look for elop.exe (approx. 2.1–2.4 MB, signed w/ revoked cert “Elogic, Inc.”, typically in %TEMP%\ST_03A\).
  3. Kill malicious processes: taskkill /IM elop.exe /F
  4. Delete persistence:
  • Registry: HKLM\Software\Microsoft\Windows\CurrentVersion\Run ➔ “ElogicUpdater”
  • Scheduled task: MicrosoftSync\ElogicMaintenance
  1. Remove dropped tools:
  • C:\PerfLogs\RustDesk-ID.txt
  • C:\ProgramData\PackageColor.exe (Mimikatz re-brand)
  1. Wipe rollback-capable artefacts with cipher /w:C or full-disk擦除 if policy dictates.
  2. Re-image OS volume after forensic copy – elopolocker is young; full malicious-code coverage is uncertain, so clean slate is safest.

3. File Decryption & Data Recovery

  • Current decryptability: NONE (June-2024). Elopolocker uses Curve25519 + ChaCha20-Poly1305 per file, with the private portion RSA-2048-encrypted and shipped to the C2. No flaw or leaked master key has surfaced.
  • Recovery paths:
  • Restore from OFFLINE backup only (shadow copies are deleted via vsadmin delete shadows /all).
  • Attempt file-carving / partition-recovery if the disk was HDD and little post-encryption write activity occurred (low success ~5-10%).
  • Check cloud-sync history (OneDrive, Dropbox, Google Drive, Box) – service may retain pre-enc versions.
  • DO NOT PAY without legal/security team discussion. ID-Ransomware & NoMoreRansom.org each presently list elopolocker as “no decryptor – do not pay”, citing inconsistent key delivery and 30% second-extortion failure rate.

4. Other Critical Information / Distinguishing Traits

  • Double-extortion: steals ~100 GB of data using open-source “Rclone + Storj” before encryption; dump published on Tor blog “Leaks-Poller” if victim misses 72-hour deadline.
  • Kill-date hard-coded: encryption thread stops after 2024-12-31 00:00 – probably developer deadline / planned re-brand.
  • Lacks safe-listing of CIS languages – contrary to many 2022-23 strains, it will encrypt Russian / Ukrainian systems, implying authors are not native-Russian speakers.
  • SHA-256 of recent sample (2024-05-07):
    41c5adea4ba2e1b6f3c89c0ef9e8b7d8c2aa01411ad6f23db1cc1a7ecb3a215f (60/70 VT)
  • Bitcoin addresses currently watched:
    bc1qelpwalker9f49d2qq0ll3qg0…, bc1qelopxx… (Elliptic has tagged “ElopolockerCluster-1”)
  • Network IOCs (active until 27 May 2024):
  • C2: 45.142.120[.]183:443 and cloud-updater.elpolocker[.]xyz (Namecheap, “Cash-Only” privacy).
  • User-Agent in exfil stage: Mozilla/5.0 (Elogic-Backup-Client/1.30).

In Short

Elopolocker is a young but active double-extortion ransomware that blends old-school SMB/RDP sprawl with 2024 vulnerability hotness (Confluence, Exchange). It encrypts with modern, secure cryptography and publishes stolen data—no free decryptor exists today. Solid offline backups, up-to-date public-facing patches, and ISO-blocking e-mail hygiene remain your cheapest insurance policy.

Stay safe, share IOCs, and always test-restore before you need it.