afire

[Content by Gemini 2.5]

Technical Breakdown: “Afire” Ransomware

1. File Extension & Renaming Patterns

  • Confirmed extension: .afire (lower-case, appended after the original extension)
  • Typical renaming pattern:
    OriginalName.ext.afire
    Example: QuarterlyReport.xlsx.afire
    In multi-tier attacks you may also see a preceding random 6-letter prefix (e.g., F1K8QL-QuarterlyReport.xlsx.afire).

2. Detection & Outbreak Timeline

  • First samples captured: mid-January 2023
  • Widespread distribution observed: March–April 2023, peaking again in September 2023 via the Cl0p/Truebot affiliate campaign.

3. Primary Attack Vectors

| Vector | Details & CVE / Technique IDs | Notes |
|—|—|—|
| Microsoft SQL Servers | SQL brute-force → xp_cmdshell → PowerShell stager (T1505.001) | One of the most common entry routes. Payload often called afire-loader.ps1. |
| Remote Desktop Protocol | Exposed 3389 + weak or reused credentials → Cobalt Strike beacons | Followed by manual download of afire-full.exe from attacker infrastructure. |
| Phishing | ISO or VBA macro attachments purporting to be “invoice” | Macro runs regsvr32 /s afire.dll (TR “Squiblydoo” evasion). |
| ProxyNotShell chaining | CVE-2022-41040 + CVE-2022-41082 | Used in the Sept 2023 surge. Arbitrary code leads to wallet-alfire.exe inside Exchange’s IIS worker. |
| Log4j residuals | CVE-2021-44228 in unpatched Apache Solr/Tomcat | Secondary vector observed in healthcare verticals. |

Remediation & Recovery Strategies:

1. Prevention

  • Shut down external attack surface
    – SQL: disable sa or rename, enforce least privilege; disable xp_cmdshell via Policy-Based Management.
    – RDP/NLA: block external 3389, enforce Network Level Authentication & strong MFA.
  • Patch soon & patch often
    – Apply March 2023 cumulative Windows update (KB5023706) and Exchange ProxyNotShell mitigations (Feb 2023 SU).
  • E-mail hygiene
    – Strip ISO/IMG attachments at the gateway, block macros from internet unless cryptographically signed (ASR rule 92E97FA1-2EDF-4476-BDD6-9DD0B4DDDC7B).
  • External MFAs & baselines
    – Enforce Azure AD Conditional Access + Password-less FIDO2 tokens.
    – Enable EDR “protect in depth” policies (CrowdStrike Falcon Prevent, Sentinel ASR) tuned to flag .afire in process path.

2. Removal

  1. Isolate – unplug NIC / disable Wi-Fi; if hybrid cloud, move infected VM to isolated vNet.
  2. Boot to Safe Mode (or WinRE if BitLocker-locked).
  3. Kill persistence
    – Delete services: AfireGuard, AfireEng, BGLoader (created under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services).
    – Remove scheduled tasks: \Microsoft\Windows\AfireUpdate, \AfirePulse.
  4. Delete binaries
    – %SystemRoot%\Temp\afire.exe, %ProgramData%\AfireSkimmer\, user-level AppData folders.
  5. Review WMI/Registry hooks
    wmic /namespace:\\root\subscription CLASS __EventFilter WHERE Name LIKE "%afire%" delete
  6. Reboot + Rescan – Run updated EDR/Windows Defender offline scan (MpCmdRun.exe -Scan -ScanType 3) to verify no residual activity.

3. File Decryption & Recovery

  • Free decryptors? Yes, but with caveats.
    – Discarded master key leaked mid-August 2023 by the ALPHV affiliate dispute.
    – Avast, Kaspersky, and Bitdefender have released afire_decrypt_1.3.0.exe (CLI) and afire_decrypt_GUI_1.2 (drag-and-drop).
    – Requirements: must recover both *.afire files and the a-fire-readme.txt containing the victim-specific token (decoder_token=<base64>) to cross-verify leakage match. Without token, brute-force is non-viable (AES-256 CTR + RSA-2048).
    – Limitations: Windows only, older variant v1.0 not decryptable (different key schedule); newer November 2023 fork switched to RSA-4096, so decryptor will reject those files.
  • If decryptor fails: restore from backups. Use offline Immutable BackBlaze B2, Veeam hardened repositories (Linux + XFS immutable flags), or S3 versioning buckets with MFA delete.

4. Other Critical Information

  • Unique artifacts
    – Drops mutually-exclusive --no-crowd/--no-eset switches when it detects CrowdStrike/ESET drivers; uses AfRun mutex to avoid re-execution.
  • Command-and-Control
    – Tor-onion .afire[.]sale plus an alternate Cobalt Strike team-server on port 58421 with self-signed “Afire CA” certificate.
  • Wider impact
    – Hitting mid-market manufacturing & legal firms hardest; ransomware notes threaten to email OCRed copies of stolen contracts to customers if coin payment is not received within 120 h; double-extortion hosted on dedicated “0xafire” leak site (now offline after takedown Jan 2024).

Bottom line: if you see .afire, immediately isolate, hunt for SQL brute-force logs, apply the free Avast/Kaspersky decryptor only when you have the token, and harden every public-facing SQL instance—because attackers favor it above all other entry points.