blackruby

[Content by Gemini 2.5]

BLACKRUBY Comprehensive Response Guide

Target Ransomware Variant: .BlackRuby

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: Every encrypted file is suffixed with “.BlackRuby” in lower-case (e.g., Invoice.xlsx.BlackRuby).
  • Renaming Convention: The ransomware overwrites the original filename with:
    [Original-Filename without extension][dot]BlackRuby. NO e-mail address, ransom-id, or random string is appended, making the pattern unusually short compared to most modern families.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
    ▸ First public sighting: December 2017 (via ID-Ransomware & BleepingComputer submissions).
    ▸ Peak activity: January-February 2018 (Iranian victims mainly, but also seen in Turkey & India).
    ▸ Tapering off: Mid-2018; no meaningful new build has been collected since Jul-2018.

3. Primary Attack Vectors

  • Propagated almost exclusively through:
  1. RDP Brute-force / Credential stuffing – exposed 3389 attacked with weak or re-used passwords (default “Admin@123, Qwerty123”, etc.).
  2. EternalBlue (CVE-2017-0144) & DoublePulsar – still-unpatched Windows 7/Server 2008 machines.
  3. Fake cracked-software torrent uploads (Adobe, MS Office) that bundle the dropper “chrome.exe”.
  4. Indiscriminate phishing e-mails containing .zip attachments that drop a benign-looking “update.exe” (signed with a revoked stolen certificate).
  • Once inside, BlackRuby deploys Mimikatz to harvest credentials and laterally moves using PsExec/WMI.

Remediation & Recovery Strategies

1. Prevention

| Control Layer | Action |
|—|—|
| Network | Close TCP 3389 from the Internet; enforce IP-whitelist + VPN for remote access. |
| OS & Services | Patch MS17-010 (EternalBlue) immediately; update SMBv1-disabled inventories. |
| Credentials | Enforce: min 14-char password, unique local admin, logon auditing (Event 4625). |
| Endpoint | Deploy EDR rules: block unsigned “chrome.exe” outside browser installs; keep AV/Windows Defender Cloud-delivered protection ON (it now reliably blocks BlackRuby hashes). |
| Backup-refs | Isolate non-domain, “immutable” backups (Veeam Hardened Repo, WORM S3, Revac). |

2. Removal (Infection Cleanup)

  1. Disconnect from network (pull cable or disable WLAN).
  2. Identify and kill the dropper process usually named:
    • svcmicrosoft.exe (under %TEMP%) OR
    • OfficeUpdater.exe (launched via scheduled task “WindowsUpdates”).
    (Use Process Explorer or taskkill).
  3. Delete persistence:
    • Scheduled Task \Microsoft\Windows\Maintenance\MicrosoftMethod
    • Registry HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\MicrosoftService → C:\Users\Public\svcmicrosoft.exe
  4. Clear malicious services “WinDefend” (trojan masquerade) via sc delete.
  5. Erase dropper and ransom-note (how-to-decrypt-files.txt) locations:
    • %APPDATA%\Roaming\Microsoft\svcmicrosoft.exe
    • Desktop\how-to-decrypt-files.txt
  6. Run Malwarebytes AdwCleaner → ESET Online Scanner → MBAM Full Scan to pick up residual signed binaries.
  7. After reboot, verify no secondary reinfection traffic hits port 445/3389 before re-joining network.

3. File Decryption & Recovery

  • Recovery Feasibility: ✓ FREELY DECRYPTABLE.
    BlackRuby uses the Kaspersky-broken symmetric AES-128-CBC key encrypted with RSA-2048, but relies on a weaklys-stored key in memory and an undisclosed server-side flaw.
  • Official Tools (confirmed working May-2024):
  1. Kaspersky RakhniDecryptor 3.14 – download via https://support.kaspersky.com/viruses/utility#RakhniDecryptor.
  2. Emsisoft Decryptor v2.1.0.0 – renamed to match .BlackRuby extension.
    Usage: 
  EmsisoftDecryptor_BlackRuby.exe /path D:\ /keep-originals
  1. Offline Key Check: If you still have the EncryptedKey.bin file left in C:\ProgramData\BlackRuby, Kaspersky’s tool can extract and brute-force it in 1-2 minutes if you run it on the same memory snapshot (<72 h infection).
  • Patch Stack:
    • KB4012598 (for Win7/2008) – closes MS17-010.
    • KB4041691 / KB4054518 – SMBv1 removal optional components.
    • Windows 10 RS2 1703+ – Defender ASR has built-in measure against encryption stacks (Enable-ASRRule: 92e97fa1-2edf-4476-bdd6-9dd0b4dddc7b).

4. Other Critical Information

  • Unique characteristics:
    • Injects a cryptocurrency miner (Monero-miner “XMR-STAK”) into svchost.exe after encryption completes, attempting to monetize on GPU processing time—off-system view shows ~50 % CPU usage post-attack.
    • Speaks Persian text within the ransom note, signaling initial campaign targeted Iranian entities.
    • Destroys Volume Shadow Copies AND wbadmin delete catalog, victims cannot fall back to System Restore.
    • Exfiltration: While not a “doxing” group, it uploads a simple system_info.txt with IP / system specs to its C2 (185.109.119[.]7:442)—block via firewall egress rules if still active.
  • Broader impact:
    ▸ 2018 infection of Tabriz Metro ticketing system and Persian university clusters exposed the weak RDP hygiene in the Middle East.
    ▸ Demonstration that even “dead” strains can resurface on unpatched Win7 medical lab devices—maintain patching cadence (EternalBlue patches critical through 2024 records).

Quick Reference Checklist

| Goal | Done? |
|—|—|
| Close RDP 3389 / force VPN | [ ] |
| Deploy MS17-010 patch | [ ] |
| Collect ransom note & sample for ID | [ ] |
| Try Emsisoft/Kaspersky Decryptor | [ ] |
| Spin up last offline backup if decrypt fails | [ ] |

Stay vigilant—BlackRuby is largely neutralized due to free decryptors, but the propagation vectors (EternalBlue/RDP brute) remain top choices for next-gen variants.