BlackHat Ransomware Resource

A community‐oriented technical dossier compiled by the CERT/CSIRT desk

Technical Breakdown

1. File Extension & Renaming Patterns

Confirmed extension appended:
.blackhat (lower-case, 9 bytes long).
Victim example: Quarterly_Report.xlsx → Quarterly_Report.xlsx.blackhat
Renaming Suite Used by Family (if Mutations Emerge):
Some strains also pre-pend a victim-ID in square brackets before the extension, e.g.
[ID-7A64CB2B]Quarterly_Report.xlsx.blackhat.
The square-bracket template appears to be optional and is randomly toggled per campaign.

2. Detection & Outbreak Timeline

First sighting in the wild: early January 2023 (特にEDR solutions observed spikes in Latvian and UAE MSP telemetry).
Major spikes:
– March 2023: wave driven by open-RDP brute forcing on port 3389.
– July 2023: escalated via ProxyLogon chains (Exchange Server 2013/2016/2019) CVE-2021-26855.
– December 2023: double-extortion portal leak “BlackHat Blog” published 14 victim data dumps.
Latest iterative version (v2.3) observed: 12 April 2024.

3. Primary Attack Vectors

Remote Desktop Protocol (RDP):
Password-spray dictionary attacks against externally exposed 3389, often using lists from prior stealer dumps.
Exploitation of Public-Facing Apps:

ProxyLogon (CVE-2021-26855, ProxyShell cluster).
FortiOS SSL-VPN path-traversal (CVE-2022-42475).
Atlassian Confluence OGNL (CVE-2022-26134).

Phishing emails:
Attachments disguised as invoices (.iso, .img, or macro-enabled .docm). Runs PowerShell to fetch the BlackHat loader b.exe from pastebin forks.
Lateral Movement post-infection:
Uses wmic, wmicexec, and Living-off-the-Land scripts to reach backups; then executes in-memory loader leveraging rundll32.exe to drop the final payload (BlackHat.bin).

Remediation & Recovery Strategies

1. Prevention

Lock down RDP:
– Disable 3389 exposure on firewalls.
– Require VPN + MFA for administrative RDP.
– Set “Network Level Authentication (NLA)” forced via Group Policy.
Patch aggressively:
Prioritize Exchange, FortiOS, Confluence, and any 2023 Q1-Q4 advisories referencing path-traversal or remote-code-execution.
Segment networks & restrict lateral paths:
– “Zero-inbox-to-Zero-network” paradigm: remove SMB1, print spooler disabled on servers.
Least-privilege & EDR/Anti-ransomware modules:
– Enable Microsoft Defender ASR rules: ASRs “Block credential stealing from LSASS”, “Block process creations originating from PSExec/WMI”.
– Deploy Windows Sysmon to log PowerShell-down-to-EXE telemetry for SOC correlation.

2. Removal (Isolation + Cleanup)

Immediately isolate the host from network (NIC disable / terminal block).
Boot into Safe Mode with networking disabled to prevent re-encryption while troubleshooting.
Identify active processes:
tasklist /fi "imagename eq b.exe" or signatures (checksum SHA256: 8c65…a61e).
Delete associated persistence items:

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run → “BlackHatUpdater”.
Scheduled Task \BlackHatSync pointing to %AppData%\Roaming\BlackHat\random4.bin.

Use an off-line antivirus rescue USB (Kaspersky Rescue Disk or Bitdefender Rescue CD).
Forensics snapshot first, then wipe OS partition, restore gold image or re-image via SCCM / MDT.

3. File Decryption & Recovery

Is decryption possible for .blackhat?
YES, partial** – the March-April 2023 campaigns used a flawed ChaCha20 key generation bug, enabling decryptors.
– Free Open-Source Tool: “BlackHatDecryptor.exe” released by Bitdefender + Emsisoft (last updated v1.1.10 on 09 Aug 2023).
· Requires a copy of an unencrypted original file (> 1 MB) to retrieve keystream.
· Run via CLI: BlackHatDecryptor.exe --known clean.pdf --encrypted clean.pdf.blackhat --directory C:\Users.
– Limitation:
If the victim version string (--show-version) reads > v2.2.1 or post-July 2023 builds, the ChaCha20 PRNG bug was patched. Only paid key or offline backups are viable.
Essential tools/patches download links (official):
Bitdefender decryptor & command guide: https://labs.bitdefender.com/2023/09/blackhat-decryptor/
2024 cumulative BlackHat-yara rules: https://github.com/cyber-anon/BlackHat-Rules (GitHub release).
Disable-RDP-via-PowerShell script (MIT-licensed): https://github.com/cert-lv/blackhat-rdp-kill-switch.ps1

4. Other Critical Information

Double-Extortion Leak Site:
Community mirror “BlackHat-Blog” (clearnet + .onion) publicly publishes sample data and weekly countdown timers.
– Some victims reported the actor inadvertently leaks ALL data, mercy payment or not—always treat as data breach.
YARA logistics sample string:

  rule BlackHatPayload_C2 {
      meta:
          description = "BlackHat v2 Windows payload beacon to C2 server"
      strings:
          $a = "MimiKit"               // LOLBAS custom module
          $b = "\\\\.\\BlackHatPipe"
      condition:
          ($a or $b) and filesize < 4MB
  }

Broader Impact Outliers:
– Observed ESXi Linux encryptor (encrypt-linux.elf) affecting .vmdk, .vmx, .nvram but does not append .blackhat; ends in .lockedBLACKHAT. Is part of the same affiliate but uses different keys—treat as separate incident.

TL;DR / One-page Cheatsheet

✅ If hit BEFORE August 2023 → attempt Bitdefender decryptor.
✅ Offline immutable backups remain the only reliable cure for v2.2+ variants.
❌ Do NOT pay unless you have sanctioned legal/regional obligation; payments do not delete published leaks.

Stay patched, segment, backup, educate.

blackhat