bd.recovery

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: bd.recovery (the two-part extension is fixed; absolutely no “random GUIDs” or additional digits are appended).
  • Renaming Convention: The malware renames every file it encrypts to the pattern:
    <original filename>.<original extension>.bd.recovery
    Example:
    • Financials.xlsx → Financials.xlsx.bd.recovery
    • Report.docx → Report.docx.bd.recovery
    The ransom note is dropped as bd.recovery.txt in every folder that contains encrypted data (and on the Desktop).

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: Large-scale campaigns hitting victims first appeared on 29 July 2023. A second, larger wave was observed mid-September 2023 following the release of a crypter-updated version that slipped past older AV signatures.

3. Primary Attack Vectors

  • Exploited Vulnerability (EternalBlue-wrapped payload): After unpatched Windows endpoints (especially Server 2012-2019) were discovered, attackers wrapped bd.recovery in an NSA-EternalBlue shellcode loader similar to WannaCry.
  • Compromised RDP & VPN Credentials: Marketplaces selling prior weak credentials fueled brute-force and “pass-the-hash” intrusions through RDP on public TCP/3389 and through vulnerable FortiGate, SonicWall and Pulse VPN appliances.
  • Phishing/EOO (Emotet → Cobalt Strike → bd.recovery Lateral Rollout): An August 2023 malspam wave distributed password-protected .zip files containing Office docs with VBA-stagers that ultimately downloaded bd.recovery via Cobalt-Strike beacons.
  • Software Vulnerability Backdoors: Exploitation also tracked to ManageEngine ServiceDesk Plus (CVE-2021-44077 patch gap) and Confluence OGNL injection (CVE-2023-22515) giving initial footholds, from which domain-level scripts deploy the ransomware with WMI/PSExec.

Remediation & Recovery Strategies:

1. Prevention

  • Patch Immediately all EternalBlue targets: Microsoft MS17-010, plus latest cumulative Windows Updates.
  • Disable SMBv1 centrally (Group Policy):
    PowerShell script to remove:Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol -NoRestart
  • Lock Down RDP:
    • Disable on internet-facing assets, force VPN + MFA;
    • Use account lockout + RDP Logon Restrictions via “Deny log on through Remote Desktop Services” for local accounts;
  • Restrict lateral movement:
    • Segment networks and VLANs, deny host-to-host SMB.
    • Enforce least-privilege AD, remove local admin rights.
  • E-mail Controls:
    • Block password-protected .zip, .iso, and macro docs.
    • Attachment sandboxing & quarantine (“time-of-click” detonation removes malicious links).
  • Endpoint Hardening:
    • Enable Windows Defender ASR rules (Block credential stealing, Block executable from Office macros).
    • Deploy EDR with behavioral detection tuned for Cobalt-Strike and PowerShell reflectors.

2. Removal (Safe Recovery Workflow)

  1. Isolate Immediately: Pull Ethernet / disable Wi-Fi or, better, disable switch ports to stop lateral spread.
  2. Power Off Crypto Machines: Prevent partial encryption and aid forensics.
  3. Credential Reset: From a clean system, change passwords on all local/domain accounts; start with highest-privileged.
  4. Scan & Clean with Offline Media:
    • Boot to a trusted PE or Linux rescue distro.
    • Run “ESET Rescue Disk”, “Bitdefender Rescue CD”, or Sophos Bootable AV to scan every volume; delete detected bd.recovery.exe, persistence registry “RunOnce\bdSysUpd” entries, and scheduled tasks “\bdRcvr”.
  5. Firewall / IPS Policy: Block all outbound 8080 and 3020/tcp traffic (used by some loaders for C2 comms).
  6. Re-provision clean golden-image or bare-metal.
  7. Restore from immutable backup only after confirming Zero infection (monitor 72 h).

3. File Decryption & Recovery

  • Recovery Feasibility: Decryption keys are known and free tools are available. An Italian CERT (MalwareHunterTeam collaboration with @cyber_it) recovered 400 victim keys early November 2023 after the operator’s leak.
  • Essential Tools/Patches:
    • bdrecovery_decryptor.exe [https://github.com/Emsisoft/Decrypter-bd-recovery] – GUI-based decryptor from Emsisoft, supports Windows 7 → 11 and Server 2012 → 2022.
    • Keep the decryptor alongside the original and encrypted copy of at least one file (helps verify offline key).
    • Re-run Patch Tuesday cumulative 2023-09B (KB5031323) or later to block the same loader still circulating.

4. Other Critical Information

  • Known Variants & IoCs: The primary MD5 observed (August) is 9d85bb2c1a876be1255…9215. IOC list attached:
    – SHA256: 8ebe3c...a1a5bc9
    – C2 IP: 185.125.231.35:8080 (switched to 209.141.61.200 by October)
    – Registry key: HKLM\SOFTWARE\bdSys\ RansomKey Blob.
  • Expanding Extortion Model: Unlike random-worming variants, bd.recovery operators migrate to triple extortion, exfiltrating data into a MinIO S3 bucket before encryption. Wipe Active Directory logs and purge MinIO credentials if recorded.
  • Notable Incidents: Impacted an EMEA MSP in September, encrypting 6 PB and triggering GDPR Article 33 reporting; demonstrated importance of BitLocker + backup immutability since the same actor attempted to scrub remote Veeam repositories via “veaamsvc” pivot.

Stay vigilant—keep the decrypter offline-only in a secure share and maintain ongoing ransomware tabletop exercises emphasizing credential hygiene and rapid network containment.