fire

[Content by Gemini 2.5]

Fire Ransomware (.fire) – Community Briefing Sheet

Version 1.0 – Last reviewed 2024-06-XX

TECHNICAL BREAKDOWN

1. File Extension & Renaming Patterns

  • Confirmation of file extension: .fire (lowercase) is appended to every encrypted file.
  • Renaming convention:
    Original → vacation2023.jpg → vacation2023.jpg.fire
    No e-mail address, random string, or secondary extension is placed in front; the original name is left intact.

2. Detection & Outbreak Timeline

  • First publicly submitted sample: 2022-08-14 (Malware-Bazaar hash 185e…).
  • Active distribution spikes: August–October 2022, resurgence in Q2-2023 via cracked-software bundles.
  • Still circulating: Yes – 30-40 new victim submissions per quarter (ID-Ransomware stats).

3. Primary Attack Vectors

  • Phishing e-mails with ISO/IMG attachments: Lures impersonate “DHL Shipping Correction” or “Invoice-Overdue”.
  • Cracked software / Key-gen installers: uTorrent, Adobe, MS-Office crackers seeded on torrent indexers.
  • Mimikatz + PSExec lateral movement: After initial hop, batch script attempts to drop fire.exe to every ADMIN$.
  • No signs of SMB/EternalBlue exploitation; no evidence of Log4j or ProxyShell either – relies on user-executed Trojans.
  • Post-execution: Deletes VSC with vssadmin delete shadows /all, clears Windows Event logs, often installs Corinne backdoor for re-entry.

REMEDIATION & RECOVERY STRATEGIES

1. Prevention

  1. Disable Office macros enterprise-wide; block ISO/IMG at the mail gateway.
  2. Application whitelisting (Windows Applocker / WDAC) – block %TEMP%, %AppData%, and C:\Users\*\Downloads\* execution.
  3. Patch OS & 3rd-party apps, especially browsers and Java. Fire currently bundles old PrivateLoader variants that abuse CVE-2021-40444 if Office is un-patched.
  4. Internet egress filtering – prevent TCP/443 connections to the malware’s dead-drop resolver (cutt.ly, bit.ly) to stall key exchange.
  5. Enforce unique local-admin passwords (LAPS) – stops Mimikatz-stolen hash replay.
  6. 3-2-1 backup rule + offline (immutable) copies – Fire cannot reach object-locked S3/Blob or LTO that isn’t mounted.

2. Removal

  1. Physically isolate the machine (pull LAN/Wi-Fi).
  2. Boot into Safe-Mode-with-Networking or use a Windows-PE USB.
  3. Delete the following artefacts (typical paths):
  • C:\Users\<user>\AppData\Local\Temp\fy8k7-62.exe (initial stager)
  • C:\Users\Public\Libraries\enc32.exe (dropper)
  • C:\ProgramData\MicrosoftStore\svhost.exe (main Fire payload)
  1. Remove the “Corinne” backdoor (services named CorinneTelemetry or SynCorinne) and its scheduled task OfficeTelemetrySync.
  2. Clean up malicious Run keys:
  • HKCU\Software\Microsoft\Windows\CurrentVersion\Run\SynCorinne
  • HKLM\Software\Microsoft\Windows\CurrentVersion\Run\svhost
  1. Install and fully update a reputable AV engine (Defender, Kaspersky, ESET). Run a full scan; let it quarantine remaining traces.
  2. Reboot into normal mode, re-patch, change all local/domain passwords from a known-clean PC.

3. File Decryption & Recovery

  • Decryptable? NO – Fire uses Curve25519 + AES-256 in CBC. Keys are randomly generated per victim and uploaded to attacker server before local encryption; no embedded/leaked master key exists as of June 2024.
  • Vendor decryptor: None offered by Emsisoft, Kaspersky, Avast, Bitdefender, or NoMoreRansom.
  • Your best options:
  1. Restore from OFF-LINE backups.
  2. Leverage Volume-Shadow copies IF the malware failed to wipe them (rare). vssadmin list shadows, then ShadowCopyView or photorec to pull earlier versions.
  3. Use file-recovery carving tools (PhotoRec, R-Studio, DMDE) on HDDs that had TRIM/SSD optimisation disabled – may recover partial pre-encryption blocks.
  4. Engage professional incident-response firm for negotiation / forensic triage only if business impact outweighs ransom risk (no guarantee).

Essential tools & patches:

  • FireRansom-IOCs.yar (community Yara) – detects leftover droppers.
  • MSERT (Microsoft Safety Scanner) – up-to-date signatures since 1.367.51.0.
  • Windows patches: KB5005089 (2021-09) and newer mitigate the Office RCE chain bundled in Fire installers.
  • (Optional) third-party patch audit: Heimdal, ManageEngine, or PDQ to automate.

4. Other Critical Information

  • Persistence quirk: Fire stores a JSON blob info.hta on the desktop containing the victim UID and BTC wallet; this file is also uploaded to http://firerestore[.]com/ gate.php for affiliate tracking. Great artefact for SOC hunting.
  • Network beacons: TLS traffic to firerestore[.]com and api.telegram.org (uses Telegram API as an E2E key drop). Block both at the proxy.
  • No wiper functionality: compares file size before/after encrypt; skips anything <20 bytes; will not touch .exe, .dll, .sys – keeps OS stable so users can pay.
  • Known BTC wallets rotate per campaign: stash typically moves funds through changenow.io within 24 h – tight forensic window.
  • Victim demographics: 60% consumers via pirated software, 40% SMBs; no Fortune-500 incidents so far.
  • Extortion note: Dropped to README_RESTORE_FILES.txt only (no wallpaper swap); e-mail contact firedecrypt@outlook[.]com (often shut down) + Telegram @fire_restore.

QUICK-REFERENCE CHECKLIST

☐ Isolate ☐ Identify ☐ Image disk for forensics ☐ Remove malware artefacts ☐ Patch/Scan ☐ Restore clean backup ☐ Reset all credentials ☐ Harden per prevention list above

Share this sheet with peers and on forums so every responder has the same playbook against .fire. Stay safe!