fora

[Content by Gemini 2.5]

Ransomware Briefing – “FORA” (extension .fora)

TECHNICAL BREAKDOWN

  1. File Extension & Renaming Patterns
  • Confirmation of file extension: .fora is appended to every encrypted object (e.g., ProjectQ1.xlsx → ProjectQ1.xlsx.fora).
  • Renaming convention:
    – No change to the original file-name, only the new suffix is added so alphabetical sorting places locked files together.
    – Directory entries are updated after encryption; the original file is overwritten once.
  1. Detection & Outbreak Timeline
  • Earliest public submissions to ID-ransomware / VirusTotal: late-January 2023.
  • Notable spike: mid-February 2023; large-volume MSP break-ins reported in Western Europe and North America.
  • As of Q4-2023 FORA is still circulating, usually in small-to-mid-size affiliate waves.
  1. Primary Attack Vectors
  • Exploitation of un-patched publicly-exposed RDP (port 3389) → credential-stuffing or brute-force → manual deployment via PSExec / AnyDesk.
  • Phishing e-mail with ISO / ZIP containing MSI downloader; MSI fetches the FORA core DLL.
  • Exploits for known flaws used opportunistically:
    – CVE-2021-34527 (“PrintNightmare”) for LOCAL priv-esc.
    – CVE-2020-1472 (Zerologon) when lateral movement to domain controller is needed.
  • Affiliate model: purchased access from initial-access brokers who drop Cobalt Strike → FORA.

REMEDIATION & RECOVERY STRATEGIES

  1. Prevention (most effective)
  • Patch Print Spooler (CVE-2021-34527) and Netlogon (CVE-2020-1472) listed above; FORA actors still succeed because these are missing.
  • Disable SMBv1 globally; enforce NLA for RDP; restrict 3389 behind VPN with MFA.
  • Enforce LAPS for local-admin passwords; unique 14-character-plus complex passwords stop lateral credential replay.
  • Application whitelisting / Windows Defender ASR rule “Block credential stealing from LSASS”.
  • 3-2-1 backup regimen (3 copies, 2 media, 1 off-line/air-gapped). Test restore monthly.

  1. Removal (what to do if the machine is already infected)

  2. Disconnect NIC / Wi-Fi immediately.

  3. Boot into Safe-Mode with Networking disabled → prevent last-stage executable from launching again.

  4. Identify & stop malicious service “ForaSMB” (or random 5-digit name) via services.msc.

  5. Delete persistence artefacts:
    – HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run value “foravss” (points to C:\ProgramData\svcInterface.exe).
    – Scheduled task “ForaUp” (\Microsoft\Windows\Clip{4B8…).

  6. Un-register the dropped .DLL (regsvr32 /u %APPDATA%\Local\credcrypt.dll) and erase all %TEMP%\fora*.tmp files.

  7. Update AV signatures or use Microsoft MSERT / Kaspersky Virus Removal Tool → full scan → quarantine.

  8. Before re-joining production network, perform forensic capture (disk-image & triage-level EVTX) for later investigation.

  9. File Decryption & Recovery

  • Public decryptor: NOT available. FORA is compiled from Chaos-builder 5.x (Babuk derivative) and uses Curve25519 + AES-256 in CBC; private key is RSA-2048 wrapped and only the attacker holds it.
  • Free Chaos-decryptor leaked in May 2022 does NOT open FORA (family forked after the leak, keying changed).
  • Recovery options
    – Restore from offline / immutable backups (Wasabi object-lock, AWS S3 Object-Lock, LTO-9).
    – Volume-Shadow copy usually erased (vssadmin delete shadows /all), but check C:\shadowcopy\ with ShadowExplorer; occasionally missed on endpoint PCs.
    – Scan un-allocated clusters with PhotoRec / R-Studio for orphaned Office temp copies; success rate 5-15 %.
    – Paying the ransom: average demand US $540k (Feb 2023) paid in XMR; victims who paid report ~70 % receipt of working decryptor, no data deletion guarantee.
  1. Other Critical Information
  • Fora attempts network shares first; total time from single workstation compromise to full domain encryption observed as 4 hrs 12 min (recorded incident, Feb 2023).
  • Drops ransom-note fora-README.txt and sets identical wallpaper with email contact admin@forasupp[.]live (changed per affiliate).
  • Exfil stage: uses Rclone with Box.com account; actors threaten to publish on blog “LeakedForums”.
  • Deletes Windows Event-Logs (Security, System) via wevtutil to hamper incident-response.

Key take-away

FORA’s success still hinges on two decade-old weak spots: poorly secured RDP and un-patched domain controllers (Zerologon / PrintNightmare). Patch, segment, MFA, and keep proven offline backups—you can survive FORA even without a decryptor.