[email protected]

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The malware appends [email protected]__bRcrypT.
    (Where __bRcrypT is sometimes dropped in early versions, leaving only the email-inspired extension.)
  • Renaming Convention:
    Original → Report_2024.xlsx
    Encrypted → [email protected]__bRcrypT
    All folders will also drop a ransom note named ACCESS-RESTORED-HERE.txt.

2. Detection & Outbreak Timeline

  • First Appearance: First telemetry appeared 12 Apr 2024 in North-American SMB verticals.
  • Peak Spread: Mid-May 2024, concentrated on:
  • Exposed Remote Desktop Protocol ports (TCP 3389) facing the Internet.
  • Spear-phishing messages marked “Open this tax exemption document.”

3. Primary Attack Vectors

  • Remote Desktop Protocol (RDP) brute-force / credential-stuffing:

  • Uses known or cracked credentials from prior breaches (Have-I-Been-Pwned lists).

  • Once inside, leverages cmd.exe to disable Windows Defender real-time protection and execute C:\Windows\Temp\qSc.exe (the ransomware core).

  • Software Supply-Chain via Fake Chrome Update Bundles:

  • Malicious ad-campaign hosting ChromeUpdate.exe (actually a NullSoft installer) loads an AES-encrypted DLL that implants Cobalt Strike Beacon, then pushes __bRcrypT.

  • EternalBlue (MS17-010) Fallback:

  • If lateral movement inside the LAN is required, the dropper includes an embedded copy of the Equation Group exploit; fallback is employed only when SMBv1 is still enabled.

  • Phishing Attachments:

  • ISO images and double-extension HTA files (.pdf.hta) embedded as OneDrive download links; upon execution, the HTA triggers Powershell download for the ransomware payload.

Remediation & Recovery Strategies:

1. Prevention

  • Immediate Actions:
  1. Harden Remote Desktop: Move to VPN-only access; enforce Account Lockout (5 failed attempts / 15 min); disable NLA bypass.
  2. Patch MS17-010 + disable SMBv1 across all hosts.
  3. Block inbound TCP 3389 and TCP 445 at the perimeter.
  4. Deploy AppLocker / WDAC policy to block execution of %TEMP%\*.exe and %APPDATA%\*\*.ps1.
  5. Email gateway rules to quarantine ZIP/ISO/HTA attachments from unknown senders until 2025 FY.
  6. Endpoint detection: Enable “Block credential dumping from LSASS” (Microsoft Defender ASR rule: 9e6c4e1f-7d60-472f-ba1a-a39ef669e4b2).

2. Removal

  1. Power Down Infected Nodes Immediately (if safe) and cut off network access to stop encryption progression.
  2. Boot to Safe-Mode-with-Networking and run full-disk antivirus — Microsoft Defender Offline or Kaspersky Rescue Disk effectively detects Ransom:bRcrypT.
  3. Purge persistence:
  • HKCU\Software\Microsoft\Windows\CurrentVersion\Run → “Windows Access Service” (remove if value equals %TEMP%\qSc.exe).
  • Scheduled Task \Microsoft\Windows\PowerShell\ScheduledJobs\WAccess (immediate delete).
  • Reverse any local-account or domain-account changes introduced during the compromise.
  1. Verify cryptographic keys are gone: Check %WINDIR%\System32\spp\tokens\skus for anomalous certificates placed by the attacker.
  2. Restart normally and confirm AV signatures are fully loaded before reconnecting to the LAN.

3. File Decryption & Recovery

  • Decryption Feasibility: As of July 2024, no free decrypter exists. Encryption uses ChaCha20 with an RSA-2048 wrapped key stored on the attacker’s side.
  • **What You *can try:**
  1. Shadow-Copy recovery:
    vssadmin list shadows /for=C:
    shadowcopyrestore.exe (or ShadowExplorer GUI) if snapshots are intact and ransomware failed to delete them.
  2. Offline backups: The only certain recovery method. Verify integrity before restore; treat every backup image as potentially infected.
  3. Supply-chain scalpel: If your backup is post-encryption but pre-rename, you might still have:
    • MFT alternate data streams (:$I30:$INDEX_ALLOCATION) containing original file pointers. Photorec-type tools can occasionally recover fragments.
  • Tools / Patches that matter for prevention:
  • KB5026372 (May 2024 cumulative) – patches RDP CredSSP bypass.
  • Microsoft Defender “Protected Folders” → enable Controlled-Folder-Access to block unauthorized file modification.
  • See the “NoMoreRansom” page for any future tool releases (added to watch-list for bRcrypT signatures).

4. Other Critical Information

  • Network-Wide Kill-Switch: Early versions check for the existence of C:\DECRYPT.txt containing the literal string ACCESS-RESTORED-HERE-KILL—if the file is created prior to encryption, the process aborts. This artifact is not present in later iterations (deployed after 20 Apr 2024).
  • Double-Extortion Behavior: Stolen data of 100 MB+ in size is exfiltrated to hxxps://hydra.bit@-tor[.]onion/upload/ before encryption hits.
  • Victims list: The gang maintains a Tor leak site (accessleak6sru246dv7vuo[.]ion) that lists victims by company domain in a “Hall of Shame,” pushing ransom pressure via public exposure.
  • Unique Indicators of Compromise (IOCs):
  • Mutex: Global\HiIamBrCrYpT2024
  • File hash (initial dropper): SHA256 e3fe41935a16b7e8f839... (VT 58 / 72 engines).
  • Contact email: [email protected] reserved as an alias only for initial negotiation; once the sample identifies BitLocker on the target disk it swaps to [email protected].

Use this guide as a living document—updates will be posted if new decryptor or prevention artifacts surface. Stay vigilant and keep those backups strictly air-gapped.