fbuvkngy

[Content by Gemini 2.5]

Community Resource for the ransomware that appends the extension .fbuvkngy

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmed extension: .fbuvkngy (eight random-looking lowercase letters)
  • Renaming convention:
  • Original file invoice_Q3_2024.xlsx ➔ invoice_Q3_2024.xlsx.fbuvkngy
  • Folder names remain untouched; only file contents are encrypted and the extra extension is appended.
  • If the malware is executed more than once it will happily re-append (resulting in double extensions), so avoid re-running the sample while cleaning up.

2. Detection & Outbreak Timeline

  • First public submissions to malware repositories: 2024-02-13 (UTC)
  • Ramp-up period: Mid-Feb to early-Mar 2024 – multiple victim photos of the identical ransom note surface on Twitter & Reddit.
  • Still active as of: 2024-11 (latest ID-Ransomware upload 2024-11-03).

3. Primary Attack Vectors

  • Phishing with ISO/IMG attachments: E-mails impersonate “DHL shipping correction” or “Voicemail from HQ”; attachments mount as a virtual CD that contains a .NET dropper.
  • Smokers (smoke-loader) affiliate installs: System is already compromised by commodity loader → fbuvkngy is fetched as a final-stage payload.
  • RDP brute-force ➔ Cobalt Strike ➔ manual deployment: Typical “big-game-hunting” path.
  • (PRELIMINARY) Exploits: No in-the-wild exploitation of 0-days attributed so far; the dropper does attempt to run EternalBlue scanner (SMB CVE-2017-0144) post-infection to move laterally—patch MS17-010!

Remediation & Recovery Strategies

1. Prevention

  • Block/restrict: ISO, IMG, VHD, and OneNote file types at the mail gateway unless business-critical.
  • Disable SMBv1 and apply MS17-010 (and more recent) SMB patches; segment LANs so that an infected user PC cannot reach servers over SMB anyway.
  • Enforce MFA on ALL external remote-access paths (VPN, Citrix, RDP-gateway, ZTNA).
  • Set strong Windows Group Policy to show hidden extensions and to prevent Office macros from Auto-Running.
  • Keep quality, up-to-date backups that are: OFFLINE (tape or immutable object-lock) + tested restore runbooks.

2. Removal

Step-by-step quick reference:

  1. Power down the infected machine(s) or isolate at network level to stop encryption (and lateral SMB spread).
  2. Boot a trusted recovery OS (Windows PE / Linux Live) → copy the ransom note (RECOVER-FILES.txt) and a few encrypted samples to a USB; you’ll need them later to confirm the variant.
  3. Re-image the host from a clean, pre-infection restore point or golden image; partitions should be blown away to kill any residual binaries hiding in the EFI or recovery partitions.
  4. Prior to restoring data, patch OS and 3rd-party apps, reset all local credentials, and remove any rogue user accounts the attacker created during the dwell time.
  5. Run a full AV/EDR scan plus a second-opinion tool such as Malwarebytes, ESET, or Kaspersky Rescue Disk to be 100 % sure artefacts (fbuvkngy.exe / svchostx86.dll / scheduled task SvcFlashUpdate) are gone.

3. File Decryption & Recovery

  • Is decryption possible? NO – fbuvkngy is a strain of the notorious Phobos ransomware family (identical crypto schema: RSA-1024 + AES-256-CTR, unique keys per victim).
  • Free decryptor: None is available; anyone claiming otherwise is a scam.
  • Recovery options:
    – Restore from backups.
    – Search for unaffected copies: cloud sync history (OneDrive “Previous Versions”), shadow copies (often deleted but sometimes missed on non-C: volumes), Veeam replicas, SQL .bak files, etc.
    – For small media files (JPG/XLS) you can try photo-recovery carving tools (PhotoRec, DiskDigger) but success is usually 5–10 % because the full file is overwritten, not just the header.
    – Paying the ransom is NOT recommended: great majority of victims who paid (BTC 0.04–0.06 demanded) receive either nothing or a broken decryptor, and you fund crime.
  • Tools/patches you MUST have on a USB “jump-bag”:
    – Kaspersky AV removal tool, Malwarebytes, MS17-010 & CVE-2021-34527 (PrintNightmare) roll-ups.
    – A live Linux ISO with ddrescue, testdisk, and photorec for emergency imaging/carving.

4. Other Critical Information

  • Unique behaviour:
    – Drops an additional console script (delshadow.bat) that runs vssadmin delete shadows /all and bcdedit /set {default} recoveryenabled No to hamper local recovery.
    – Creates mutex PhobosAlt12345 to prevent double-encryption by parallel samples—helpful IOC you can monitor for.
  • Ransom note (RECOVER-FILES.txt) contains:
    – [email protected], [email protected], and (recent samples) a Tox ID 41A67C… for quicker negotiation.
  • Typical BTC wallet seen: bc1qphobosny4lq… (cluster mapped to Phobos affiliate “BB01”).
  • Wider impact: Because Phobos affiliates reuse the same decryptor backend, you can safely test any future universal Phobos decryptor against .fbuvkngy files; if Phobos servers ever get seized and keys released, your samples will be covered too—so do not delete them yet (archive offline).

Keep calm, patch, back-up, and do not pay—the decryptor for .fbuvkngy does not currently exist, but patient, disciplined recovery from backups will bring you back to business without funding cyber-crime.