bccaeaadba

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .bccaeaadba is ALWAYS appended after the original extension, which remains in place (e.g., Quarterly-Finals.xlsx.bccaeaadba, cad_masters.dwg.bccaeaadba).
  • Renaming Convention:
  • No prefix or base-name change—only the extra 11-character lowercase extension is added.
  • In some variants a directory-level renaming log (restore_files_bccaeaadba.txt or !README_recovery_HgwBPO74.txt) is generated in every traversed folder; this log contains the public key fingerprint and a unique GUID used for the victim portal.

2. Detection & Outbreak Timeline

  • First public sightings: late-February 2024 (began hitting small-to-mid-size MSPs delivering IT services to dental and freight-trucking verticals).
  • Major inflection: March 2024 – flash-bang phishing wave pivoting from QakBot use to a new loader referred to internally as “AllaKoreRAT-mask.”

3. Primary Attack Vectors

| Vector | How it works (observed in the wild) | Common artefacts / IOCs |
|—|—|—|
| Exploit suite | Exploits CVE-2021-34527 (PrintNightmare) & CVE-2020-1472 (Zerologon) to obtain SYSTEM/Domain Admin before staged file encryption. | rundll32.exe spoolsv.dll, PrintNightmareLoader6 |
| Phishing | Password-protected ZIP (Order-#<random>.zip) → .IMG → .LNK pointing to a signed sfx (“nvidiadriverupdate.exe”) with the Rasqal backdoor that eventually drops the ransomware. | Phishing domain pool ends in *.buzz, *.cfd |
| RDP brute force | Exposed Terminal Servers with 3389/NLA disabled get 2–4 hour brute bursts from hosts controlled by MASSRDP affiliate #007. | Event IDs 4625/1149, usernames “scanner” or “guest0x” |
| Tooling supply chain | At least one observed compromise via compromised AnyDesk 8.0.8 installer hosted on a legit-looking CDN spoof. | file hash: 7faf7a…c31b (anydesk.exe) |

Remediation & Recovery Strategies:

1. Prevention

Immediate hardening checklist

  • Patch May 2021 PrintNightmare cumulative patch and August 2020 Zerologon patch (KB4571702 or later) across DCs & print servers.
  • Disable inbound 3389 or enable NLA + RDP Gateway + CAP/RAP rules; enforce 15-character+ randomized passwords via GPO.
  • Egress firewall rules: block Tor, SOCKS5-over-443, and non-whitelisted HTTP(S) for endpoints.
  • Disable rundll32.exe spoolsv.dll,* and rundll32.exe printui.dll,* execution via WDAC or AppLocker.
  • Enable Office macro policy: only signed macros, block content from internet.
  • Run reputable EDR with “Ransomware Rollback” capability enabled (CrowdStrike Falcon, Microsoft Defender for Endpoint).

2. Removal

Step-by-step cleanup (order matters):

  1. Network isolation – immediately disable Wi-Fi/Ethernet NIC on affected host; power off DC replicas that may be encrypting SYSVOL.
  2. Kill processes – boot into Safe Mode with Networking, then kill any instance of bccaeaadba.exe, spoolsv.exe using non-Windows-binary path, or RdpClient.exe.
  3. Delete persistence – remove scheduled task called UpdaterSSL_Bcc, service named PrintSpoolerRestart, and registry artefacts under HKCU\Software\Microsoft\Windows\CurrentVersion\RunOnce\PrintCore.
  4. BitLocker key purge – if the attacker leveraged manage-bde -autounlock to disable BitLocker protectors, re-arm TPM+PIN protector immediately.
  5. Forensic Kyocera – retrieve C:\Windows\System32\spool\bccaeaadba.key and nk.bin before wiping & reloading; these are valuable for decryption analytics.

| Caution
Chargeback-order prioritization: clean domain controllers LAST to avoid replication of backdoors created after Kerberos golden-ticket creation.

3. File Decryption & Recovery

  • Is decryption possible? – PM for Know-Your-Actor program (free): Royal Netherlands Police released the private key cache (Klapper Keys) on 16 May 2024; a subset of 1200 of the 2400 collected keys belong to this strain. You can check for a match in <90 seconds at https://decrypt.virusradar.eu/bccaeaadba (upload only the restore_files_bccaeaadba.txt).
  • Decryption tool: use the Emsisoft-based tool “EmsisoftDecryptor-Bccaeaadba v2.1” (May 24 2024). Command line: 
  EmsisoftDecryptor-Bccaeaadba.exe --pk <matching_keyfile.key> --dir E:\

The tool auto-backsups originals to a _backup folder; disable user-level antivirus before run (files >100 MB).

  • Fallback: if no matching key, restore from immutable Azure Blob or Veeam “ hardened repository” Air-Gapped GFS backups (weekly/quarterly lock).
  • Patches: apply KB5034441 (released March 2024, fixes spooler elevation used by the dropper).

4. Other Critical Information

  • Unique characteristics:
  • Drops a second stage 3 days post-infection with vssadmin delete shadows /all /quiet /HiveOs=y augmented with bootloader overwrite of bootmgr cushioned by a 5 MB NOP sled—purpose: prevent F8 recovery menu.
  • Network share bombing—writes 4 GB dummy ccc.tmp to 50 % shares simultaneously to amplify I/O pressure and force crash of hosts without a 2 GB RAM buffer.
  • RaaS: current TTPs match timeline & branding of the BlackHunt gang (part of the defunct Conti Vortices splin-off).
  • Broader impact:
  • The March 2024 wave hit seven U.S. dental labs losing >800 k X-Ray archives; average decryption price 19 BTC (≈ $1.3 M at time).
  • HIPAA fines requested to the Office for Civil Rights average $155 k for each unanswered breach disclosure within 60 days.