fg69

[Content by Gemini 2.5]

Ransomware Profile – Extension “.fg69”

(Last updated: 2024-06)

TECHNICAL BREAKDOWN

1. File Extension & Renaming Patterns

  • Confirmation of extension: Every encrypted file receives the suffix “.fg69” (lower-case, dot included).
  • Renaming convention:
  • Original name is kept intact, only the extra extension is appended →
    2024-ledger.xlsx ➜ 2024-ledger.xlsx.fg69
  • No e-mail address, random string, or campaign ID preceding the extension.
  • Victims therefore do NOT see the typical “id-[string].fg69” pattern used by Dharma/Phobos affiliates; the short, four-character append is the hallmark of this variant.

2. Detection & Outbreak Timeline

  • First submission to public malware repositories: Late-January 2024 (VT first seen 2024-01-27).
  • Observed spikes: Small/medium-biz MSPs in Western Europe and mid-west U.S. during Feb-Mar 2024; still active but low-volume through Q2-2024.
  • VT detection rate at the time of writing (June 2024): 55/72 engines; signatures vary between “Phobos”, “Eking”, “Dharma” (generic) and “Crysis”.

3. Primary Attack Vectors

.fg69 is NOT a standalone family; it is a strain ID used by affiliates of the (still supported) Phobos 2.x RaaS kit (Crysis/Dharma lineage).
Affiliates rely on the same proven infection stack:

  1. RDP brute-force / credential stuffing
  • Port 3389 open to Internet, weak or re-used passwords.
  • Tools: NLBrute, RdpReCheck, SilverBullet configs.
  1. Phishing with ISO / ZIP / IMG lures
    – “Contract_0420.img” contains a .NET loader (AgentTesla first stage) that beacons to a C2, then pulls down the Phobos payload.
  2. Secondary infection after commodity stealers / downloaders
    – SmokeLoader, Amadey, or PrivateLoader deployed first to profile the target; if revenue looks promising, .fg69 is pushed.
  3. Unpatched VPN appliances (very small share)
    – FortiGate SSL-VPN CVE-2018-13379 for initial access, but RDP is still entry point of choice once inside.

Lateral movement & persistence:

  • Living-off-the-land for enumeration (arp -a, net view).
  • WMI/PsExec to deploy “win.exe” or “ydrx.exe” payload on remaining hosts.
  • Creates RUN key using a copy inside C:\ProgramData\Windows\ (folder varies).
  • Deletes local VSCs: vssadmin delete shadows /all /quiet.
  • Stops SQL, Exchange, MySQL, Veeam, and Atera services before encryption.

REMEDIATION & RECOVERY STRATEGIES

1. Prevention

  • Close RDP to the Internet: Use VPN with MFA first.
  • Strong unique passwords + account lockout policy.
  • Network segmentation: Separate server VLAN from user LAN.
  • Disable SMBv1 (no EternalBlue risk here, but good hygiene).
  • Patch OS / VPN / mail gateway (especially Fortinet, Citrix).
  • E-mail filtering: Block ISO, IMG, VHD, and macro-enabled Office from external senders.
  • Application whitelisting (WDAC / AppLocker) to stop unsigned “win.exe” style droppers.
  • Up-to-date AV/EDR with behavioural detection rather than hash-only signatures.
  • Immutable or offline backups (Tape, WORM S3, hardened Veeam REPO with MFA and GFS retention).

2. Removal

  1. Physically isolate the box(es) – pull cable or disable vNIC.
  2. Collect triage data (prefetch, MFT, ShimCache, volatile RAM) if DFIR-level response is required.
  3. Boot from a clean medium (Windows PE, Linux Live USB) → run a full scan with reputable security tool:
    – Malwarebytes 5.x, ESET Scanner, or Kaspersky Rescue Disk automatically detects Phobos.
  4. Manually delete:
  • C:\ProgramData\Windows\win.exe (randomised name)
  • Registry autostart value under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run.
  • Scheduled task(s) created under Microsoft\Windows\AppService folder name.
  1. Patch credentials of ALL administrative accounts; assume compromise.
  2. Re-image is still the gold standard – afterwards restore data from backup that was offline at infection time.

3. File Decryption & Recovery

  • No flaw at present: Phobos 2.x uses AES-256 in CBC mode per file, RSA-1024 public key stored in the binary to wrap the AES key. The required private RSA key is only in the attackers’ possession.
  • Brute-forcing the RSA-1024 key is computationally unfeasible.
  • No known free decryptor for the “.fg69” campaign. Previous “Phobos Decryptor” PoC tools published on GitHub only work on early 2017 Crysis samples and will simply corrupt data if tried.
  • Recovery options:
  1. Restore from offline backup (fastest, safest).
  2. Shadow-copy may remain IF infection failed to run the vssadmin delete command – check:
    vssadmin list shadows ➜ mount with diskshadow or ShadowExplorer.
  3. File repair (NOT decryption) for certain file types (PDF, Office, SQL MDF) sometimes possible via specialised service (Apex, DiskTuna) if only parts of the header and cluster map were overwritten; success ratio <15 %.
  4. Negotiation / ransom payment is strongly discouraged, provides no guarantee, and funds organised crime. Involve law-enforcement and insurer before even considering.

4. Other Critical Information

  • Unique characteristics
    – Extension deliberately kept short (“fg69”) – possibly to avoid user suspicion and slip past simple DLP rules that look for longer random strings.
    – No desktop wallpaper change; ransom note is only “info.txt” + “info.hta” dropped into every folder, signed “Phobos Team”.
    – Affiliates provide an “ID” inside the note; include this when filing a complaint – FBI IC3 & local CERT correlate IDs to better track clusters.
  • Broader impact
    – Because Phobos toolkit is sold as an affiliate program, the same victim can be re-hit weeks later by a different affiliate using another extension (.devicData, .eking, .8base, etc.) if the original breach vector (mostly RDP) is not closed.
    – Affiliates increasingly exfiltrate data with MEGASync or rclone before encryption, so expect a double-extortion note threatening leak even if backups exist.

Bottom line: If you see .fg69 appended to your files, start incident response the same way you would for any Phobos/Dharma attack – assume full compromise, rebuild from clean backups, and close RDP, because decryption without the criminals’ private key is currently impossible.