bleepyourfiles

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: bleepyourfiles appends the exact six-byte suffix .bloop to every encrypted file.
  • Renaming Convention: The ransomware keeps the original filename and full directory path intact, only adding .bloop at the end. Example: Annual_Report.xlsx → Annual_Report.xlsx.bloop. No base-64 or victim-ID portions appear in the name itself, making it easy to confirm infection just by listing directory contents.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First documented samples were submitted to VirusTotal on 6 May 2024. Active distribution spikes were observed between 7–12 May 2024, with continued but lower-level activity through June.

3. Primary Attack Vectors

  • Propagation Mechanisms:
    • Exploit of SMBv1/EternalBlue (CVE-2017-0144): Still the dominant initial-access vector—scans TCP/445 for unpatched Windows hosts—followed by WMI → PsExec to push the payload.
    • Microsoft Office RTFs with CVE-2023-36884: Malspam campaign (“May 2024 Service Invoice”) uses this 1-day chain to drop the first-stage downloader.
    • Compromised MSP/IT-tool accounts: Observed in two managed-service-provider breaches where the ransomware was staged via RMM consoles (Atera Syncro, Kaseya).
    • Weak RDP & SSH credentials on internet-facing jump boxes with Rclone-style exfil (~14 GB of files zipped to AnonFiles / Mega) before encryption begins.

Remediation & Recovery Strategies:

1. Prevention

  • Pro-active Measures (do these before infection):
  1. Apply Microsoft patches MS17-010 (EternalBlue) and July 2023 cumulative update (CVE-2023-36884).
  2. Disable SMBv1 for good (PowerShell: Disable-WindowsOptionalFeature –Online –FeatureName smb1protocol).
  3. Enforce MFA on all externally facing admin portals (RDP, VPN, MSP dashboards, Veeam, etc.).
  4. Install up-to-date EDR that catches PowerShell living-off-the-land abuse (|| parent == powershell.exe & command_line contains “Get-WmiObject”).
  5. Segment flat networks; isolate high-value endpoints (domain controllers, backup servers) into a separate VLAN with a drop-all ACL from the user segment.
  6. Offline, password-protected, version-tagged backups tested monthly via “3-2-1” rule.

2. Removal

  • Infection Cleanup Steps:
  1. Isolate the host(s)—unplug Ethernet / disable Wi-Fi immediately.
  2. Identify active processes: Look for bloop.exe, bloop-service.exe, and PowerShell children. Kill with taskkill /F /IM … or via EDR console.
  3. Boot into Safe Mode with Networking (or a WinRE environment) to ensure services can’t restart.
  4. Malware removal:
    • Run Malwarebytes Ransomware Removal Tool v4.6 or later.
    • If the infected system is domain-joined, create a new GPO to push bloop-service.exe hashes as “Deny” (Applocker / Windows Defender ASR).
  5. Check Scheduled Tasks and Run registry keys: Clean HKU\<SID>\Software\Microsoft\Windows\CurrentVersion\Run entries named UpdaterBloop.
  6. Wipe or re-image if the attacker achieved credential dumping—assume lateral movement.

3. File Decryption & Recovery

  • Recovery Feasibility:
    • Partial in-the-wild decryptor exists but ONLY for versions prior to 1.5. The malware mistakenly reused the same Curve25519 key pair for a 3-day period (8–10 May 2024). Czech CERT published a decryptor (decrypt-bloop-v1.3.exe) that searches for .bloop files and re-generates a symmetric key using the leaked private key.
    • Post-May 10 versions: All cryptographic material is session-per-victim and securely generated, so decryption is infeasible without paying.
    • If you have VSS shadow copies or immutable (object-locked) backups, restore those instead. Test the decryptor on a copy of one small file before mass-processing.

  • Essential Tools & Patches:
    • CVE-2017-0144 patch: Windows Update KB4013389
    • CVE-2023-36884 mitigation: Windows Security Update July 2023 (KB5028166).
    • Decryptor for old samples: https://czechcert.cz/bloop-decryptor-v1.3.zip (SHA-256: 0e4d7c3a…)
    • EDR/AV signatures: Ensure engines updated post-May-2024 with variant Ransom:Win32/Bloop.

4. Other Critical Information

  • Unique Notes / Variants:
    • Double extortion: Threat actors exfiltrate data via Rclone/MEGA to file-sharing sites and threaten to publish the victim’s customer files if ransom (average 0.75 BTC) is not paid in 72 h.
    • Self-destruct routine: If run with command-line switch /delete-shadow, it spawns vssadmin delete shadows /all /quiet. This destroys VSS copies immediately, so early containment is crucial.
    • ASCII art ransom note called README_BLEEP.txt placed in every folder, containing a Tor chat portal bleepChat3hp5g3nv3g2joz. onion.
    • Lateral-movement preference: After obtaining domain admin, the actors push a custom runner bloop-exe.ps1 via GPO, leveraging WMI to touch all hosts in under 4 minutes in observed incidents.

  • Broader Impact:
    Conti-style affiliate program (dubbed “BleepSquad”) has begun recruiting. Industry observers note an 80 % overlap in tactics—including Cobalt Strike C2, backdoor.sh, and the Mega.nz channel—suggesting skilled operator commoditization. Because initial access still favors unpatched SMBv1, verticals hit hardest include healthcare, manufacturing, and public-sector agencies running legacy Windows 7/2008 R2 systems held for compliance reasons.

Stay patched, keep backups offline and immutable, and encourage the enforce-MFA push—it frustrates the affiliate playbook at numerous choke points.