bqtlock

[Content by Gemini 2.5]

BqtLock Ransomware Community Resource

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The ransomware appends the exact extension .bqtlock to every file it encrypts.
  • Renaming Convention: The malware keeps the original file name and appends it with the extension without adding an ID, email address, counter, or any other prefix/common suffix that some families use (e.g., invoice.docx becomes invoice.docx.bqtlock). This clean, single extension pattern simplifies detection rules but also makes it harder to distinguish between a legitimate file type and an encrypted one at a glance.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: The first verified sightings of BqtLock began in mid-January 2024, with a sharp spike in submissions to public sandboxes and support forums through February 2024. The family appears to be still in an early, aggressive distribution phase at the time of this writing (Q2 2024).

3. Primary Attack Vectors

  • Propagation Mechanisms:
  • Credential-Affecting Phishing: Attack lures arrive as ISO/IMG (mountable archive) attachments that contain malicious LNK or BAT files initiating PowerShell download of BqtLock binaries.
  • Exploitation of CVE-2023-34362 (MOVEit Transfer) & CVE-2023-22515 (Atlassian Confluence) – attackers obtain initial foothold on internet-facing application layers, then pivot laterally to domain controllers and push the ransomware with basic PsExec / WMIC scripts.
  • Exposed Remote Desktop Protocol (RDP) Sessions: Brute-force or password-spray against TCP/3389 remains the second most frequent entry point. After pass-the-hash techniques, the malware is dropped by vssadmin.exe delete shadows /all /quiet followed by BqtLock.
  • Fake Software Cracks & Key Generators: Torrents advertising cracked versions of popular utilities and games have been bundled with a silent BqtLock installer hidden inside NSIS installers.

Remediation & Recovery Strategies:

1. Prevention

  • Immediate Hardening Checklist:
  • Patch all externally facing instances of MOVEit Transfer, Confluence, and any product mentioned in CISA’s 2024-Ransomware IOC feed.
  • Remove or disable SMBv1 on every legacy workstation/server unless business-critical applications mandate it—there have been no reports of BqtLock leveraging EternalBlue yet, but lateral SMB abuse is common once inside.
  • Enforce strong MFA on all RDP, VPN, and firewall management accounts; block inbound RDP (TCP/3389) at the perimeter or gate it through a zero-trust broker that inspects full sessions.
  • Isolate privileged administrative VLANs (jump boxes) and block lateral DNS/NetBIOS broadcasts across client subnets to hinder beaconing.
  • Deploy application whitelisting (e.g., Microsoft Defender Application Control in “enforced” mode) to prevent unsigned executables from running out of %LOCALAPPDATA%, %TEMP%, or external ISO mount points.

2. Removal

  • Step-by-Step De-Imaging/Clean-up Process:
  1. Immediately power off or isolate infected hosts via network segmentation to stop further encryption.
  2. Boot into Windows Safe Mode with Command Prompt or boot from an offline rescue disk (Bitdefender Rescue CD or Kaspersky Rescue Disk).
  3. Run an EDR or AV scrub: Malwarebytes, ESET, Sophos Central, etc., have already tagged the main BqtLock payloads as Ransom.Win32.BQTLOCK.*. Ensure signature age < 24 h.
  4. Kill scheduled tasks:
    • schtasks /query /fo table /v | findstr "bqt" → identify and schtasks /delete /tn "<TaskName>" /f.
    • Check for new services named bqtlock or random 6–8 character strings (sc query).
  5. Remove the persistent registry autorun keys:
    • HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
    • HKCU…\Run
  6. Wipe only the OS partition if you have verified, immutable backups; otherwise, do a forensic disk-image first before re-imaging or clean install.
  7. Re-patch third-party clients (especially Java, Adobe Reader) to reduce return vectors.

3. File Decryption & Recovery

Recovery feasibility: Decryption is currently impossible.

  • No free decryptor exists because BqtLock uses an AES-256 per-file key protected by an RSA-2048 public key and the attacker keeps the private key off-site.
  • Independent ransomware watch-lists (e.g., NoMoreRansom.org, McAfee Ransomware Decryptors) continuously scan for encryption weaknesses; none found yet.
  • Essential Tools/Patches:
    • Employ shadow-copy recovery scripts (shadowcopymaint.ps1) if VSS was not purged; check \System Volume Information.
    • Use bare-metal backup tools (Veeam, Rubrik, Druva) that leverage immutable S3 object-lock buckets or hardened Linux pull-only repositories.
    • Keep offline/air-gapped copies (tape, WORM disk, cold storage).

4. Other Critical Information

  • Unique Characteristics:

  • BqtLock inserts a 32-byte zero-padded footer at the end of each encrypted file; this footer contains the encrypted AES key + SHA-256 metadata—forensic teams can leverage it for tracking re-use attacks.

  • Fast Encryption Speed: PerfLab tests show ~210 MB/s on modern NVMe, so less than 30 minutes to walk a 500 GB endpoint.

  • Embedded Monero (XMR) Address Only: No email or Tor site needed—victims are instructed to pay 1.2 XMR (~$250 at May 2024 rates) to a static wallet and attach transaction ID inside a built-in web-note (bqtlock.url).

  • Broader Impact:

  • Target Landscape: Early telemetry analysed by SecurityWeek identifies initial victims in mid-sized European accounting firms, UK local councils who recently migrated to MOVEit, and a North-American MSP that lost 50+ client domains in a single propagation wave.

  • Double Extortion Decommissioned: Unlike classic double-extortion groups, BqtLock does not appear to exfiltrate data for leak-based pressure. The ransom note simply threatens destruction of the private key if no payment is detected within 72 h.

  • Copy-cat Concerns: The simple builder code (already floating on underground forums) suggests we may see derivative strains; proactively adjust IDS/SIEM rules for .bqtlock extension via REGEX: \.\bqtlock$ on file-write/HTTP PUT events.

Bottom line: BqtLock is a fast, financially motivated strain that currently lacks a public remediation decryptor. Swiftly isolate, patch, and rely on tested, immutable, offline backups. Stay subscribed to NoMoreRansom for any future decryptor release.