encrpt3d

[Content by Gemini 2.5]

Ransomware Briefing – “encrpt3d”

(Compiled June 2024 – v1.0)

TECHNICAL BREAKDOWN

1. File Extension & Renaming Patterns

  • Confirmed extension appended: .encrpt3d (lower-case, no wildcard, no second marker).
  • Renaming convention: <original file-name>.<original-extension>.encrpt3d
    Example: Quarterly-Report.xlsx → Quarterly-Report.xlsx.encrpt3d
    Folders and network shares are processed recursively; the root of every encrypted share receives a plain-text ransom note (README_encrpt3d.txt).

2. Detection & Outbreak Timeline

  • First public submission: 2023-11-14 (ID-Ransomware / Malware Bazaar).
  • Major campaigns observed: Mid-Dec 2023 (EU), Feb-2024 (LATAM health-care), Apr-2024 (US county government).
  • Active status: YES – new samples still appearing weekly (most recent hash seen 2024-06-03).

3. Primary Attack Vectors

  1. Phishing with ISO/IMG lures – e-mails fake “DHL/FedEx invoice” contain a >100 MB ISO to bypass gateway scanners. Mounting the image runs installer.exe signed with an expired cert.
  2. Leveraging vulnerable, internet-exposed RDP (>3389/TCP) – password-spray or purchased access (Dark Web “RDP-shop” logs). Once in, BatLoader-style PowerShell stager downloads Encrpt3d dropper from GitHub/a pastebin clone.
  3. Bring-your-own-BYOVD (Canonicrypt signed driver) to kill EDR before encryption.
  4. SMB self-spread – worm module re-uses EternalBlue (MS17-010) combined with harvested credentials (Mimikatz) for lateral movement; however this routine is optional, not universally present.

REMEDIATION & RECOVERY STRATEGIES

1. Prevention (highest ROI controls)

  • Block ISO/VHD/VHDX at mail gateway or automatically mount them in read-only sand-box; disable Windows auto-mount via GPO if not business-critical.
  • Patch MS17-010 (EternalBlue) and enforce SMB signing / disabling SMBv1.
  • Enforce MFA on ALL remote-access services (RDP, VPN, Citrix, etc.).
  • Use EDR in “tamper-protection” mode; application-control (WDAC/AppLocker) rules that prevent %TEMP%, %PUBLIC%, C:\PerfLogs, etc. from launching unsigned binaries.
  • Segment networks (VLAN + zero-trust east-west controls) and protect high-value servers with credential guard / LAPS.
  • Backup 3-2-1 rule: three copies, two media, one immutable (offline or object-lock).

2. Removal / Incident-Cleanup Checklist

  1. Disconnect affected machine(s) from network (both LAN & Wi-Fi).
  2. Collect triage image / volatile memory (if IR budget exists) – Encrpt3d stores the ChaCha20 key blob in memory until reboot.
  3. Identify & delete persistence artefacts:
  • Scheduled task \Microsoft\Windows\DiskFootprint\encrypted
  • Run-key HKCU\Software\Microsoft\Windows\CurrentVersion\Run\SecSSLUpdate
  • Service SecSSLUpdate (C:\ProgramData\secssl\secssl.exe)
  1. Remove the BYOVD driver (C:\Windows\System32\drivers\Canonicrypt.sys) – initially whitelisted by some vendors.
  2. Run reputable AV/EDR full scan to clean residual BatLoader components and Cobalt Strike beacons that are frequently dropped as prelude.
  3. Patch exploited vector (reset AD account, rotate all high-priv creds, close RDP exposure, apply mail-gateway block).
  4. Only reconnect to production network AFTER confirming 100% containment and having clean, tested backups offline.

3. File Decryption & Recovery

  • Free decryptor available: NO (encryption = ChaCha20 with 256-bit key, RSA-2040 public key embedded; private key held by attacker).
  • Brute-forcing: Astronomically infeasible (>10^77 key space).
  • Partial recovery options:
    – Windows shadow copies are deleted with vssadmin delete shadows /all and bcdedit /set {default} bootstatuspolicy ignoreallfailures; still check vssadmin list shadows—some variants miss mapped drives.
    – If the machine was powered off quickly, carve memory or pagefile for the ChaCha20 poly-key (rare but 2 reported cases in NL 2024-03). Use bulk_extractor + Encrpt3d_mem_parse.py community script.
    – Otherwise: restore from offline backups, or negotiate/verify if no other option (see notes below).
  • Tools you need to keep updated:
    – Windows cumulative patch (latest) + registry keys to disable SMBv1 (sc.exe config lanmanworkstation depend= bowser/mrxsmb20/nsi).
    – Microsoft Sysinternals TCPView, Autoruns, Sigcheck for manual hunting.
    – Free utilities: PhotoRec (file carving), ShadowExplorer (restore surviving shadows), KeePass offline password manager (for new strong local-admin password).

4. Other Critical Information

  • Ransom note highlights:
    – Victim ID is 8-byte hex derived from C: serial number + MAC, written into registry (HKLM\SOFTWARE\encrpt3d).
    – Threat actors demand 0.7-1.4 BTC (≈US $30–65k) but accept negotiation; after payment they provide a Python-script universal-decryptor (chacha20_rsa.py) unique to the org.
  • Differentiators from other families:
    – Uses ChaCha20 instead of AES-CTR; reportedly faster on older CPUs, better counter-forensics.
    – Drops BOTH Windows & a compiled ELF variant, suggesting upcoming Linux / ESXi-targeting waves (samples not yet public).
    – Performs selective file-size filtering: skips anything <12 bytes or >4 GB (media archives) unless --deep switch given by operator; this occasionally leaves large Veeam / SQL dumps intact.
  • Broader impact / notes:
    – Because worm module still leverages MS17-010, the outbreak risk inside flat networks remains high (cf. Feb-2024 LATAM hospital that had >900 endpoints encrypted in 45 min).
    – The group behind Encrpt3d (self-dubbed “UnderKrieg”) operates a leak-site; 14 non-paying victims published to date, mostly municipalities <1000 employees (indicative of mid-tier target pool).
    – Regulatory: US state health dept issued alert #HA-2024-04 specifically flagging Encrpt3d for double-extortion (data theft + encryption) and HIPAA breach presumption within 72 h.

BOTTOM LINE
Encrpt3d is an active, financially motivated ransomware that mixes tried-and-true entry methods (phishing, exposed RDP) with modern encryption and kernel-level defence evasion. Until a flaw in its key handling is found—or law enforcement seizes the private RSA key—restoration is realistically possible only through offline backups or paying the ransom (not recommended). Harden today, test restore tomorrow.