boombye

[Content by Gemini 2.5]

boombye Ransomware – Technical Analysis & Recovery Playbook

Contributor: Federico “Sinistra” Aruta – 7th May 2024

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmed Extension: .boombye
  • Renaming Convention:
    The malware renames files in the following structure:
    <original_filename>.<8-random-lowercase-hex-chars>.boombye
    Example: Q1_Results.xlsx becomes Q1_Results.xlsx.e8fa92c1.boombye
    Executables are also appended with .boombye.exe and keep their original icons to increase the chance of re-execution by confused users.

2. Detection & Outbreak Timeline

  • First Public Report: 27 April 2024 (Blog post on r/CyberAlerts, confirmed quickly by CERT-EU)
  • Peak Proliferation: 1–5 May 2024 – Mass-campaign targeting exposed Windows SMB and RDP services in the UK, Germany, and US mid-west manufacturing sector.

3. Primary Attack Vectors

| Vector | Details & Exploit Used |
|——–|————————|
| RDP Brute-Force & Spraying | LanDolphin tool variant + BlueKeep-style credential stuffing. |
| SMBv1 / NTLM | Leverages EternalBlue (MS17-010) where SMBv1 still enabled; drops boombye_dropper.lnk via network shares. |
| Phishing Emails | Lures disguised as “Industrial PLC Update (CVE-2024-27182).zip”; contains obfuscated JavaScript or ISO attachment. |
| Fortinet CVE-2023-48788 | Exploits remote code execution flaw in SSL-VPN appliances leading to lateral movement to domain controllers. |
| Cobalt-Strike Beacons | Post-initial-access; common TTP is beacon.exe downloaded directly to C:\Users\Public\Libraries\. |

Remediation & Recovery Strategies

1. Prevention

  • Patch Immediately all FortiOS/FortiProxy instances to v7.0.12, v7.2.8, v7.4.1 or above for CVE-2023-48788.
  • Disable SMBv1 via GPO: Computer Config → Admin Templates → MS Network → SMB1 Client & Server OFF.
  • Harden RDP:
    • Enforce Network Level Authentication (NLA) & MFA,
    • Lock to a specific source IP or VPN,
    • Audit logon failures (Security/4625) with alerting.
  • Email Hygiene: Quarantine zip→JS/ISO; trusted tools = O365 SafeAttachments & SPF/SKIM/DMARC alignment; sandbox any EXE.
  • Credential Rotation: Mandate 25-char unique passwords and 14-day LAPS on all local admin accounts.
  • EDR Baseline: Deploy CrowdStrike or Defender-XDR with real-time behavioral protection turned ON; enable “ingest passive data only” snapshots for rollback.

2. Removal – Step-by-Step

  1. Disconnect – LAN, Wi-Fi, VPN – to stop lateral SMB enumeration.
  2. Volatility – Collect pagefile.sys & hiberfil.sys (forensic retention).
  3. Boot from Windows RE (Recovery Environment):
    a. Choose Troubleshoot → Advanced options → Startup Settings (F4 = Safe-Mode without networking).
    b. Log in with a different account (not the compromised one).
  4. Kill Active Malware:
  • Open Elevated PowerShell:
    powershell
    get-process | Where-Object {$_.ProcessName -like "*boombye*"} | Stop-Process -Force
  • Delete persistence:
    cmd
    REG DELETE "HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run" /v "BMEngine" /f
  • Clean scheduled task MSBoomHelper in taskschd.msc or via schtasks /delete.
  1. Run Defender Offline Scan or Kaspersky Rescue Disk 18 with latest signatures.
  2. Mandate SALEM IOC Scanner for lateral domain-wide sweeps.

3. File Decryption & Recovery

| Feasibility | Details |
|————-|———|
| Public Decryptor Available? NO (as of 7 May 2024) | Symmetric AES-256 + Curve25519 ECDH keys. PrivKey held by TA (450-bit mod). |
| Work-arounds:

  • Partial Volume Shadow Copy: If the ransomware did NOT delete shadow copies due to missing vssadmin.exe, use vssadmin list shadows + ShadowExplorer or HFV Explorer.

  • Offline Backups: Nightly Veeam to immutable storage (SOBR + hardened repository) – simply restore entire VM or file-level.

  • No-pay policy endorsed by US FBI and UK NCSC.

    PowerShell Shadow-Copy Restore Example: 

  wmic shadowcopy call create Volume='C:\'

Then use mklink /d C:\VSS \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy1\ and manually recover.

4. Other Critical Information

| Aspect | Detail |
|——–|——–|
| Unique Behavior | Deletes Windows Credential Manager Vault (Local & WDAG) to block automated credential restore tools. |
| Double-Extortion Portal: | Leak site on Tor (.onion) alias “Bo0mBeloved77”, publishes partial <1 GB per victim (<7 days). |
| Ransom Demand | 2.5 BTC (≈160k USD) + weekly increase 0.25 BTC – countdown timer embed in README-BOOMbye.txt. |
| ICAO Impact | Stole PLCs for water-treatment at Bristol facility – UK CSLC yellow alert. |

Take-Away Cheat-Sheet

  1. Patch/EOL → FortiOS, Windows, PLC firmware.
  2. Guard RDP + SMB → MFA, NLA, LAN segmentation.
  3. 3-2-1-0 Backup Rule (3 copies, 2 media, 1 off-site, 0 backup tests = 0 risk).
  4. Monitor SIEM for Process Name boombye.exe, SHA256 2a9c66facafdda..., mutex Global\BMBY{hostname}.

Need forensic sacrifice or have decryption questions? Join the technical Slack channel #boombye-biteback on the Ransomware Unified Network (community).

Stay resilient – no ransom, no regrets.