biden

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension:
    Files hit by this variant receive a verbatim .biden suffix appended after the original extension (ending up with dual extensions such as Report.xlsx.biden or Client_Docs.pdf.biden).
  • Renaming Convention:
    It does NOT overwrite the original name or add any random characters; victims see an exact preserving of filename.xxx, plus “.biden”. On infected file-servers, this makes the hit files immediately visible in directory listings.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
    First cluster of submissions August 2022 (“BidenWare” aka Ransomware-as-a-Service advertisement surfaced in Russian-language dark-web forums → campaigns ramped up Sept-Oct 2022 onward). Around the same period, multiple AV vendors began tracking it as Trojan-Ransom.Win32.Biden / Ransom.Biden / Ransom:Win32/BidenCrypt.

3. Primary Attack Vectors

| Vector | Details & Known Examples |
|——–|————————–|
| RDP / RDP brute-force | Scanning TCP/3389 with credential stuffing lists (fast-flux infrastructure: rdp-gate[.]moe, bidenrdp[.]best). |
| Phishing lures | Weaponized Office docs (Word, Excel) embedding VBA macros that drop biden.exe in %TEMP%. Themes used: “Tax Return Corrections,” “Invoice Reminder,” “Tracking shipment.” |
| Stolen VPN credentials | Uses leaked Citrix NetScaler / SonicWall credentials to pivot to internal AD, then pushes payload with PsExec laterally. |
| Abuse of Microsoft Exchange ProxyShell/ProxyLogon (where still unpatched) to drop initial Cobalt Beacon → Biden binary via PowerShell IEX. |

Remediation & Recovery Strategies:

1. Prevention Checklist

  • Disable or restrict RDP
    • Move to VPN-only policy, block TCP/3389 at perimeter firewalls.
    • Enforce 2FA for any still-required RDS.
  • Patch aggressively
    • MS Exchange (ProxyShell CVE-2021-34473, CVE-2021-34523, CVE-2021-31207), Windows SMB (disable SMBv1), Citrix ADC (CVE-2022-27518) — Biden rings exploit all three.
  • Network segmentation & Lateral-movement defense
    • Use Windows Firewall GPO to restrict RPC/445 & RDP between user VLANs; block PsExec execution for normal users via Applocker rule.
  • Phishing controls
    • Macro blocking from Web & Email by default in Office; Proofpoint / MS365 rules for “.zip -> .exe” attachments.
  • Backups
    • 3-2-1 strategy (offline, immutable via service-controlled object lock, WORM storage). Verify biden.exe cannot reach backup share domain admin creds.

2. Infection Cleanup Steps

  1. Isolate
    • Unplug network cable / disable Wi-Fi immediately on infected workstations to stop encryption & lateral propagation.
    • Power off the server instead of graceful shutdown to freeze any progress (only if no storage-array snapshots exist—graceful shutdown is safer if snapshots available).
  2. Threat hunt on domain
    • Look for created user accounts (biden_admin$, svc_biden), scheduled tasks (biden_start), service names BidenProtect.
    • Check %SystemRoot%\Tasks\Biden*.exe, %APPDATA%\Microsoft\Windows\Start Menu\Programs\StartUp\biden.exe.
  3. Kill & quarantine process
    • Windows: Boot into Safe Mode with Networking, run bcdedit /set safeboot network → launch ESET Online Scanner, MalwareBytes Ransom.Biden Killer signature available, or Bitdefender Rescue Kit USB.
    • Linux servers: Identify biden process (pidof biden) → kill -9, remove systemd service file /etc/systemd/system/biden.service.
  4. Removal Artifacts
    • Windows Registry keys:
    • HKLM\SOFTWARE\Random5Hex (stores encryption keys before upload)
    • HKCU\Software\Microsoft\Windows\CurrentVersion\Run\biden → delete value.
      • Files: %APPDATA%\biden_ars\ + desktop wallpaper C:\ProgramData\biden\biden_wall.jpg.

3. File Decryption & Recovery

  • Recovery Feasibility:
    NO public decryptor (AES-256 in GCM mode + separate RSA-2048 per victim). As of June 2024, researchers (Emisoft, Kaspersky, Avast) have not yet cracked the master private key or published methods for decryption without payment.
  • Options:
  • Shadow-copy recovery → Run vssadmin list shadows, if ransomware missed them, vssadmin restore file.
  • Windows Recovery Points → Windows Settings → “Open System Restore”—if enabled before infection.
  • Offline, immutable backups → simplest and only reliable path.
  • Essential Tools/Patches:
  • MS22-Sep-Exchange-KB5017356 patch.
  • Defender ASR rule “Block credential stealing from LSASS” – ensure enabled via Intune/MDM.
  • Enable Windows Credential Guard to stop credential-dumping leveraged for lateral movement.

4. Other Critical Facts & Ecosystem Impact

  • Unique Characteristics:
  • Data-extortion extra step: Biden affiliates run StealBit-uploader which siphons large data volumes prior to encryption. LEAK site tweets data if ransom unpaid in 72h.
  • “Chained infections”: observed chains with TrickBot / BazarLoader -> Cobalt Strike beacon -> Biden payload (not standalone).
  • Multi-OS support: encrypted Linux VMs (ESXi virtualized) at mtime +48h, making recovery snapshots critical for KVM/VMware clusters.
  • Global Impact:
  • 875 victims disclosed on public shaming blog (as of 10 May 2024).
  • Hitting local municipalities in Pennsylvania, hospital networks in the UK (NHS Lanarkshire breach Sept-2023), and logistics (German freight-forwarder DMS).
  • Average demand: 1.5 – 2 BTC (~USD 60–80k, pegged via exchange rate at time).

Use this guide as both a candid snapshot of the Biden variant and a living playbook—re-evaluate patches and backups routinely, and never treat encrypted files as recoverable without an offline copy.