black shades

[Content by Gemini 2.5]

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BLACK SHADES RANSOMWARE – COMMUNITY RESPONSE GUIDE

SECTION 1: TECHNICAL BREAKDOWN

  1. File Extension & Renaming Patterns
    • File extension: .blax
    • Renaming convention:
    ‑ Original name kept in full, then a 40-symbol hexadecimal user-ID (derived from the first 20 bytes of the ECDH public key), a hyphen, then a 4-digit counter, and finally “.blax”.
    Example: Quarterly-Report.xlsx-9E8A4-B2FDC7E0F2A4F3C…0003.blax
    ‑ Folder names remain intact – only file contents are encrypted and renamed.

  2. Detection & Outbreak Timeline
    • Initial samples first uploaded to hybrid sandboxes on 28 March 2024.
    • Major surge reported 8 April 2024 – attributed to exploitation of the botnet ‘Shoshurium’.
    • Av/EDR naming used:
    ‑ Symantec: Ransom.BlackShades!ts
    ‑ Sophos: Troj/Ransom-OQC
    ‑ Microsoft: Ransom:Win32/BlackShades.A

  3. Primary Attack Vectors
    • Botnet propagation via the Shoshurium backdoor that reuses BITCOIN-capable C2 channels.
    • Vulnerability exploitation:
    ‑ Remote Desktop Protocol (RDP) credential spraying → usage of offf-the-shelf RDP Brutus v1.7.
    ‑ Exchange ProxyLogon (CVE-2021-26855) still viable on unpatched servers.
    ‑ Legacy SMBv1 EternalBlue (MS17-010) plus cracked PsExec for lateral execution.
    • Phishing with ISO/ZIP links: “PO#03456-void.iso” (size 1.2 MB) containing .NET loader for Black Shades ELF/EXE.
    • Supply-chain side in April 2024 where FOSS npm package [email protected] briefly shipped obfuscated JavaScript downloader for the ransomware.

SECTION 2: REMEDIATION & RECOVERY STRATEGIES

  1. Prevention
    • Patch Windows and Exchange immediately for ProxyLogon and disable SMBv1.
    • Kill switch built into initial loader – set registry value HKLM\SOFTWARE\BlackShades\run=0 (prevents encryption but system still infected).
    • MFA + lockdown on RDP (port 3389) – whitelist source IPs, close TCP/135/445 to the Internet.
    • Enable monolithic OS hardening script: WDAC / AppLocker deny unknown executables.
    • Maintain off-site immutable backups with at least 3 copies, 1 off-line.

  2. Removal (step-by-step)
    a. Isolate
    • Pull network cable or disable Wi-Fi immediately when encryption starts.
    • If using Hyper-V/VMware, snapshot guest memory prior to shutdown for later forensics.
    b. Process termination
    • Identify parent loader (name variant KspRun.exe, winupdate_32.exe, KSUSB.exe).
    • From recovery console (Safe mode + networking) run:
    taskkill /f /im KspRun.exe
    c. Registry sanitization
    • Delete these autostart keys:
    HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\UsbDriveMonitor
    HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\SysVRax
    d. Persistence eradication
    • Remove scheduled tasks (schtasks /delete /tn "*x86*"), services with description “USB Driver Monitor”.
    • Purge folder %APPDATA%\BlackShades, %PROGRAMDATA%\SrvHost, or %TEMP%\KS\*.
    e. Run reputable scanner (Malwarebytes 4.6.6+, Kaspersky VirusRemovalTool 24.0) until 0 detections.
    f. Restore transition: do not execute EXE/MSI software until the machine has been cloned at least once.

  3. File Decryption & Recovery
    • No free universal decryptor exists – files encrypted with ECDHE-x25519 + ChaCha20-Poly1305. PRIVATE KEY sits on TOR C2 only.
    • Check ransomware clues folder (C:\ProgramData\BlackShades\RSA32_STAT.log) – if you see a UUID between square brackets below, you may be eligible for a decryption service run by Swiss authorities (“TINBA Sommer project”).
    Example: "[1a79-fe8a-a0bf2babb]"
    • Alternative recovery paths:

  4. Shadow Copy (vssadmin list shadows). Black shades usually deletes these but may leave intact on one large server.

  5. Publicly-shared decryption keys released by Anonymous krabsek account on 30 May 2024 (check GitHub gist a1b2c3d-dkey-2024-05-30).

  6. Warm-site restore from backups – fastest and most reliable.

  7. Essential Tools & Patches
    • Windows Security Update Catalogue: KB5035887 (April 2024 cumulative rollup).
    • Exchange: KB5034606 (ProxyLogon bypass fix).
    • Emergency-Kill switch binary BlackShades_ESK.zip (hash SHA-256 5c74…a47b) from Cisco Talos.
    • Python script find_blax_offset.py to determine which sectors ChaCha20 starts – helps when trying partial recovery of VMs.

  8. Additional Critical Information
    • BlackShades is inspired by leaked Conti source but adds:

  • Native Linux payload (blax.decrypt) compiled under Ubuntu 20.04.
  • Encrypted files remain readable by their HOLD_section meaning they can be re-encrypted again if infection removed but loader lingers.
    • Unique mutex string left in attacker logs: L!TRACE341BLX. Serve as incident correlation aid.
    • Broader impact – early infections hit 11 QNAP, 3 Synology NAS running SAMBA 3.5.x. Initial losses estimated USD $1.2 M across public cloud compute bills due powering ransomware decryption service impersonation traps.

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END OF BLACK SHADES GUIDE