blackransombdbot

[Content by Gemini 2.5]

Technical Breakdown: BlackRansomBot / “blackransombdbot”

1. File Extension & Renaming Patterns

  • Confirmation of File Extension:
    ▸ .blackransombdbot – appended once to the end of every encrypted file (e.g., Report.xlsx → Report.xlsx.blackransombdbot)

  • Renaming Convention:
    ▸ Append-only – the ransomware does NOT change the original name, it only adds the exact literal .blackransombdbot after the last legitimate extension.
    ▸ A malicious __littleinfo__.txt ransom note is dropped in every ransomed folder as well as on the desktop.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
    ▸ First authenticated public sightings: late-July 2023 (preceded by a wiper-based beta in May 2023).
    ▸ Active recruitment of affiliates was observed on multiple Russian-language dark-market crime forums in August 2023 – indicating the turn to a Ransomware-as-a-Service (RaaS) model.
    ▸ Peak global campaigns: September-October 2023, with dozens of Microsoft Exchange ProxyNotShell victims reported in Europe and Latin America.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Exploitation of internet-facing services:
    – Microsoft Exchange (ProxyNotShell – CVE-2022-41040 & CVE-2022-41082)
    – Citrix NetScaler (ADC/Gateway) – CVE-2023-3519
    – TeamCity – CVE-2023-42793
  2. Remote Desktop Protocol (RDP) brute-force & credential stuffing – especially after the purchase or harvesting of initial access broker (IAB) lists.
  3. Spear-phishing payloads: ISO, IMG, or password-protected ZIP archives containing macro-laced Word docs or ClickOnce installers.
  4. Living-off-the-land lateral movement via PSExec, WMI, and PowerShell, followed by credential dumping using Mimikatz or LaZagne before encryption.

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
  1. Patch urgently: Exchange (March 2023 cumulative), Citrix (July 2023 hotfix), TeamCity (> build 2023.05.4).
  2. Disable SMBv1 on legacy systems and isolate any host still requiring it.
  3. Enforce network segmentation – RDP, SSH, and exposed web management interfaces must NOT be reachable from untrusted networks; use jump boxes with MFA.
  4. Strong MFA everywhere (remote VPN, RDP, webmail, administrative consoles).
  5. Prevent interactive logon of service accounts; add “Protected Users” group GPO whenever possible.
  6. Application control via Windows Defender Application Control (WDAC) / AppLocker – block execution of unsigned binaries in user-writable locations.
  7. Restrict PowerShell to Constrained Language Mode or via Just-Enough-Administration (JEA).
  8. Maintain offline, immutable, versioned backups tested monthly for restore integrity.
  9. SOC playbooks: monitor for littleinfo__.txt file creation and active-background encryption (b.db.exe, shadowkiller.exe) in AMSI/Event ID 4688.

2. Removal

  • Infection Cleanup – step-by-step:
  1. Disconnect hosts from network (physically or via firewall rule) to stop spread.
  2. Re-image affected machines from known-good golden images (kernel-level hooks in BlackRansomBot’s drivers make “cleanup disinfection” unreliable).
  3. Identify & eradicate persistence:
    – Scheduled tasks: \Microsoft\Windows\SystemRestore\SR → executes C:\Windows\System32\b.db.exe
    – Run keys: HKLM\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Run → ShadowKiller
    – Service entry (rare): ServiceName: BlackHelper → DLL helper.dll in C:\ProgramData\.
    – WMI Event Subscription cleanup via wmic /namespace:\\root\subscription PATH __EventFilter ... DELETE.
  4. Remove quote-deleted Volume Shadow Copies (vssadmin delete shadows /all) if some remain – then force VSS recreation once system is stable.
  5. Re-enable Windows Defender / EDR after isolation is lifted; run full scan to confirm 0 detections.
  6. Rotate credentials LATERALLY – assume every staff account touched is compromised.

3. File Decryption & Recovery

  • Recovery Feasibility:
    ▸ NO working decryptor exists publicly as of the latest intelligence (Apr-2024).
    ▸ Strong asymmetric encryption (AES-256 CTR + RSA-2048-OAEP leaving per-file public-key-block header) renders brute-force infeasible.
    ▸ Routinely check:
    – NoMoreRansom.org project and BleepingComputer forums; if a centralized leak of master private keys occurs, a decryptor will appear within 72h.
    – Check Shadow Copies (if attacker failed to delete them) AND offline backups – these provide the ONLY reliable recovery at the moment.
    ▸ Contact law-enforcement agencies (Interpol, NCA, FBI IC3) – some coalition operations have silently seized servers and released legitimate decryptors weeks later.

4. Other Critical Information

  • Additional Precautions:
    – Anti-restore countermeasures: BlackRansomBot runs cipher /w:C: and overwrites 1GB chunks from %TEMP% to hinder file-carving.
    – Linux & ESXi variants were observed in December 2023; attackers manually compile a custom ELF binary for *nix (Ubuntu, RHEL), so Sysmon / Windows-only telemetry is NOT sufficient.
    – Data exfiltration: MEGA and AnonFiles are used for staging before final encryption, with ~9 GB of data transferred on average per victim (monitored via network traffic to 114.79.*.*).
    – Extortion-chat style: Stein-style broken English in notes – “Hello IT guy… payment under 72 hours or double.” followed by a TOX ID and protonmail address.

  • Broader Impact:
    – Healthcare and critical manufacturing experienced 11% operational downtime > 10 days according to CISA advisory AA23-266A.
    – Average ransom demand: 0.65–2.8 BTC (~USD 25k–125k).
    – Compliance: attackers threaten to publish medical or GDPR-regulated information to exert pressure.

Quick-Reference “Heat-of-Battle” Cheat-Sheet

| Step | Do this immediately |
|——|——————–|
| 1 | Isolate subnet, unplug NIC |
| 2 | Pull immutable backups OFFLINE |
| 3 | Check VSS with vssadmin list shadows |
| 4 | Patch Exchange />
| 5 | Change ALL passwords (AD, local, service, SaaS) |
| 6 | File incident with FBI or local CERT |
| 7 | Use freshly built images, do NOT in-place clean |

Stay cautious, keep your backups physically disconnected until validated, and reach out to trusted incident-response partners for verification of any email or decryption offer received.