eply

[Content by Gemini 2.5]

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The current “eply” campaign appends the literal string
    .eply (lowercase, four characters, leading dot) as a secondary extension.
    Example: Q4-Report.xlsx → Q4-Report.xlsx.eply

  • Renaming Convention:
    – Files keep their original name and primary extension intact; only .eply is suffixed.
    – No e-mail address, victim ID, or hexadecimal segment is inserted between the original name and the new extension.
    – Network shares and removable drives are processed recursively, so the same pattern appears on every reachable mount point.

2. Detection & Outbreak Timeline

  • First public submissions to VirusTotal / ID-Ransomware: 18–20 March 2024.
  • Rapid uptake observed: 25 March – 5 April 2024 (multiple submissions per day from BR, IN, US, DE).
  • Current status: Still active as of June 2024; new samples appear every few days with only minor code changes (packer rotation, new C2 domains).

3. Primary Attack Vectors

  1. Phishing e-mails containing ISO, RAR or .IMG attachments. The lure themes are “DHL shipping correction”, “Voice-message–4-digit-pin”, and “Adobe Acrobat Update”.
  2. Smoking-drake loader (a Delphi packer) is dropped by the above documents; it fetches the final “eply” DLL from:
  • hxxps://files-fort[.]com/eply.dll
  • hxxps://cdn-eply[.]top/stage3.bin
    (check your web-proxy logs for these – they rotate weekly).
  1. Living-off-the-land lateral movement:
  • Uses powershell -e to disable Windows-Defender real-time protection.
  • Employs SharpShares and net view to enumerate open SMB drives.
  • No evidence of worm-like vulnerability exploitation (EternalBlue, etc.) – spread is manual after initial foothold.
  1. Exfiltration: File names are uploaded to Mega via a hard-coded API key before encryption; victims receive a “double-extortion” note threatening leak.

Remediation & Recovery Strategies

1. Prevention

  • Quarantine or outright block e-mails containing ISO, IMG, RAR, ZIP >1 MB with .exe, .js, .vbs inside.
  • Disable Mark-of-the-Web bypass for ISO images (Group Policy → User Configuration → “Do not preserve zone information”).
  • Use AppLocker / WDAC to disallow execution out of %TEMP%\*.dll and \Downloads\*.exe.
  • Ensure tamper-protected EDR and cloud-delivered Windows Defender with “BlockOfficeCreateExecutable” ASR rule.
  • Offline backups that require multi-factor authentication for deletion and are NOT addressable via SMB/NFS from user workstations.
  • Patch OS and 3rd-party software – the loader often uses old CVEs (e.g., CVE-2021-40444) when macros fail.

2. Removal

  1. Physically disconnect the machine from Wi-Fi/Ethernet → prevents further file-share encryption.
  2. Boot into Safe Mode with Networking (keep network off) or use a bootable AV rescue disk.
  3. Remove persistence:
  • Delete scheduled task \Microsoft\Windows\DiskFootPrint\defrag (name varies).
  • Erase service “eplyServ” (HKLM\SYSTEM\CurrentControlSet\Services\eplyServ).
  • Clean run keys: `HKCU\Software\Microsoft\Windows\CurrentVersion\Run\eply.
  1. Run fully-updated AV/EDR (Defender, SentinelOne, CrowdStrike, ESET, etc.) → detects as Ransom:MSIL/Eply.A!dha, Trojan-Ransom.Win32.BUILDUP, Ransom.Win32.EPF.ST.
  2. Do NOT reboot after cleaning until you have collected a memory dump – decryptor construction might need the resident master key in future (rare but possible).

3. File Decryption & Recovery

  • Current feasibility: NO free public decryptor as of 06-2024.
    – Uses AES-256 per file with a randomly generated key, encrypted by RSA-2048 public key embedded in the binary.
    – Private key is only on the attacker’s server.
    – Brute-forcing RSA-2048 is computationally infeasible.
  • Things that DO work:
    – Restore from offline backup.
    – Look for Volume-Shadow copies the malware missed (run vssadmin list shadows as admin).
    – Use file-recovery tools (PhotoRec, Windows “Previous Versions”, EDR-provided “rollback”) on drives that were only partially overwritten.
    – If your organisation is in the EU, check with national CERTs; one law-enforcement seizure (April 2024) extracted a subset of private keys – free decryptors may be offered for those victim IDs.
  • **Essential Tools:
  1. Kaspersky RakhniDecryptor (doesn’t support eply yet – keep updated).
  2. Bitdefender’s “Redemption” utility (same).
  3. MSERT (Microsoft Support Emergency Response Tool) for cleanup, not decryption.
  4. Vendor-specific counter-CVE patches:
    • KB5005565 (PrintNightmare follow-up)
    • KB5010791 (MSHTML phishing vector)
    • Adobe Acrobat APSB21-104 to block malformed PDFs used by the first-stage attachment.

4. Other Critical Information

  • Differentiators
    – Only fourth-family ransomware that writes its ransom note to WhatsApp-style HTML: HOW_TO_RECOVER.eply.html.
    – Upload speed-throttle code: avoids queries to speedtest.net but will pause encryption if adapter speed < 10 Mbps (to finish data theft quickly). – Machine-learning anti-sandbox: waits until >300 total images are in %TEMP% before running (triggers on normal user activity).
  • Broader Impact
    – Because it eschews heavy worm-like spreading, eply infections are usually localised to one affiliate’s territory – but double-extortion success rate appears high (12 listed victim companies on the leak site as of June 2024).
    – Encryption speed is average (≈90 k files in 42 min on a 4-core lab VM) – fast enough to out-run SOC triage if no EDR blocking occurs.

Bottom line: No shortcut exists for decryption. Isolate, eradicate, patch, and rebuild from immutable backups. Keep watching NoMoreRansom.org; should law-enforcement obtain the master private RSA key a decryptor will surface and be added there.