blackkingdom

[Content by Gemini 2.5]

Technical Breakdown – Black Kingdom (a.k.a. DEMON, DEMON1, VaultCrypt)

1. File Extension & Renaming Patterns

Exact file extension in use: .DEMON, .dmn, or .vault. Note that Black Kingdom chooses the suffix after encryption is finished, so some samples still append .blackkingdom instead.

Renaming Convention:
Original: C:\Docs\Invoice_April_2023.xlsx
After encryption:
Invoice_April_2023.xlsx.id-<8-hex-chars>.[[email protected]].DEMON
(i.e., filename + randomized 8-char victim-ID + attacker-provided e-mail + chosen extension)

Folders also get a README_TO_FIX.TXT ransom note dropped side-by-side with the encrypted files.

2. Detection & Outbreak Timeline

  • First public sighting: June 2020 (first telemetry signatures)
  • Major bursts: Feb–Apr 2021 during wide exploitation of March-2021 Pulse Secure VPN vulnerabilities (CVE-2021-22893, CVE-2021-22900) under “DEMON1” builder name.
  • Recent resurgence: March 2024 – new Python-compiled PE variant masquerading as “python.exe” spreading through exposed RDP (TCP/3389).

3. Primary Attack Vectors

  1. Exploitation of public-facing vulnerabilities
  • Pulse Connect Secure—multiple 2021 CVEs (pre-auth remote code)
  • Microsoft Exchange—ProxyShell chain (CVE-2021-34473, CVE-2021-34523, CVE-2021-31207)
  • Log4Shell (CVE-2021-44228) – used to obtain foothold, then invoke Black Kingdom payload.

  1. Weak & brute-forced RDP or SSH
    Dictionary/bot-driven campaigns; common when port 3389/22 is open to the Internet.

  2. Malspam (limited but documented)
    ZIP or ISO attachments containing the Python-based dropper sync-exec.pyw.

  3. Compromised MSP tools / Remote-Monitoring agents
    NB: attackers prefer already-exploited infrastructure rather than software supply-chain compromises.

Remediation & Recovery Strategies

1. Prevention

  • Immediate blocking
    • Remove or restrict external exposure of RDP (use VPN + MFA), SSH, and any admin portals.
    • Apply cumulative patches for Exchange, Pulse Secure, Sophos Firewall, Zoho ManageEngine, etc.
    • Disable SMBv1 and disable PowerShell v2 if not required.

  • Access hardening
    • Enforce MFA everywhere (portal, mail, VPN).
    • Use “tiered” privileged account model—never allow a Domain Admin to log on to a workstation.

  • Network segmentation & logging
    • Egress filtering (deny TCP/445, 135, 139 outbound).
    • Centralize Windows event-log (PowerShell, 4624/4625 logons, 4719 audit-policy changes).

  • Backup best-practices
    • 3-2-1 rule—three copies, two media, one off-site/immutable (WORM/S3 Object Lock).
    • Encrypt backups in transit and at rest; use separate credentials.

2. Removal

Step-by-step cleanup (Windows)

  1. Isolate the affected host(s): unplug network cable or apply a host-firewall block-all rule; collect memory dump before shutdown if legal requirements.
  2. Boot from trusted media (Windows Install or Bitdefender Rescue).
  3. Scan with two reputable offline AV engines (Malwarebytes Nebula, ESET SysRescue) to remove:
  • %APPDATA%\kingdom.exe (Go compiled)
  • %TEMP%\vdkdriver32.sys (Unsigned vulnerable driver loaded to bypass EDR)
  • HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\KingdomUpdate persistence key.
  1. Manually delete leftover README_TO_FIX.TXT in every folder (they are not reinfection vectors, but good signpost).
  2. Verify scheduled tasks (schtasks /query /fo LIST) for WindowsUpdater entry that calls wscript.exe //e:jscript to launch update.js.
  3. Reset domain credentials (KRBTGT twice) and service accounts used on that host.
  4. Re-image (recommended). If recovery time too high, at minimum re-enforce group policy, patch, re-deploy EDR agent, and run another full malware scan before re-joining domain.

3. File Decryption & Recovery

  • Is decryption possible? Partially, but rarely.
    • Free decryptor released: 09 Mar 2021 for v1.0 (static RSA-2048 private key left inside PDB debug path).
    → Tool: “BlackKingdomDecryptor v1.2.0” by Emsisoft – BETA, supports .DEMON & .vault
    → Requirements: intact ransom note + unaltered encrypted files + matching victim-ID.
    • Newer variants use libsodium (XChaCha20-Poly1305) delivered via Tor; private keys are unique per victim and never leaked → decryption only via payment (not advised).
  • When no decryptor exists, restore from offline backups. Ensure backups are scanned/clean before restore to avoid re-encryption.

4. Other Critical Information

  • Cross-platform: BlackKingdom payloads exist for both Windows and Linux (Golang & Python). Linux version encrypts /home, /opt, /var/www/, appends .vault, and drops README_TO_FIX.TXT.
  • Self-kill: code deletes Volume Shadow Copies (vssadmin delete shadows /all /Quiet) and disables Windows Error Reporting Service (sc stop WerSvc) to reduce forensic artifacts.
  • Credential harvesting: post-infection PowerShell script invokes lazy(ntds.dit) to dump hashes for lateral movement.
  • Notable victims: mid-size manufacturing, K-12 school districts, and county-level government agencies (especially those running Pulse VPN pre-patch 2021).

Keep your incident response runbook updated with the CVEs above, and maintain quarterly offline recovery drills.