akgum

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: akgum ransomware consistently appends “.akgum” to every encrypted file.
  • Renaming Convention: The pattern follows the scheme <original filename> . <random 6–7 hex-digit victim ID> .akgum (e.g., budget_2024.docx.7F3B9A2.akgum, inventory.xlsx.00E1A3F.akgum). The victim ID is unique per infected host and is also written into the ransom note for tracking.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: The first confirmed akgum samples appeared in mid-February 2024, with a sharp rise in public submissions and incident reports during March 2024. Peak activity was observed the week of 14–21 March across Western Europe and North America.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Exploitation of CVE-2023-34362 MOVEit Transfer SQLi – automated scripts drop akgum payloads days after data exfiltration.
  2. Phishing – emails impersonating DocuSign or Adobe invoice updates with password-protected ZIPs containing a dropper.
  3. RDP Brute-forcing / Credential-stuffing – clusters of infections tied to IPs selling Shodan-scraped open RDP lists.
  4. Drive-by via “FakeUpdate” (SocGholish) – victims are prompted for a fake browser update JS that downloads Cobalt Strike → akgum.
  5. Supply-chain compromise – one managed-service provider (MSP) incident saw akgum pushed via legitimate software-update channel trusted by 120 downstream customers.

Remediation & Recovery Strategies:

1. Prevention

  • Immediate Safeguards:
    • Patch CVE-2023-34362 and all MOVEit-related advisories (Progress & CISA mitigation script).
    • Disable SMBv1 everywhere; enforce NLA & 2FA for all externally facing RDP.
    • Heavy e-mail filtering: strip password-protected archives or sandbox them 2+ hours before delivery.
    • Disable default RDP 3389; expose via VPN with MFA certificates.
    • Application-control (AppLocker / WDAC) policy deny unsigned binaries running from %TEMP%, %APPDATA%\*.exe, and network shares.
    • Turn on MFA for any remote-management software (ScreenConnect, Atera, AnyDesk, etc.).

2. Removal

  1. Immediately air-gap affected hosts (Wi-Fi, Bluetooth, LAN).
  2. Boot into Safe Mode and run forensics-level AV/EDR:
    – CISA IOC list SHA256: 1caf8f2e003ee…c4e6522f.akgum.exe
    – Any.run & MalwareBazaar both tag Ransom.Akgum.A.
  3. Delete persistence keys:
    reg delete "HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run" /v akgumupdate /f
    reg delete "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce" /v WinAknn /f
  4. Scan and remove Cobalt Strike beacons in %APPDATA%\Roaming\Cookies\ and scheduled tasks named MicrosoftEdgeUpdate.
  5. When certain malware is gone, change every credential that touched the machine (local, domain, SSO).
  6. Re-image or restore only after confirming zero residual persistence (compare hashed MFT vs. known-good baseline).

3. File Decryption & Recovery

  • Recovery Feasibility: At the time of writing (December 2024), no public decryptor exists for akgum. Encryption uses AES-256 in CBC mode (files) + RSA-2048 (per-victim key pair sent to C2). Keys are wiped locally after encryption completes and are not stored in ransom note.
  • Available Avenues:
    • Check your backup retention: akgum does not encrypt offline/cold-storage.
    • Inspect Volume Shadow Copy (vssadmin list shadows) – akgum calls vssadmin Delete Shadows /all, but occasionally fails on server editions.
    • Attempt file-carving from disk slack space & unallocated clusters with PhotoRec if encryption missed very large (>4 GB) files.
  • Published Tools/Patches:
    – CISA #StopRansomware: akgum-specific IoC CSV (v3.2)
    – Microsoft Defender 1.405.1177.0+ (update to signature version published 19 March 2024)
    – ED-20-01 MoveIt MSSQL command-signatures Snort & Suricata rules.

4. Other Critical Information

  • Unique Characteristics:
    • akgum’s ransom note (“RESTORE-FILES.txt”) drops in every folder and includes a prettified ASCII logo plus a link to the victim-specific Tor chat page that forces captchas in French.
    • It terminates 100+ security processes by MD5 hash (CrowdStrike report <24 h after outbreak).
    • The malware begins encryption in parallel threads limited by free RAM to avoid crashing low-spec hosts, which makes detecting large-scale entropy spikes harder in EDR.
  • Broader Impact:
    – Over $7.8 M demanded across ~150 confirmed infections; the gang focuses on small-to-medium municipalities, law firms, and managed print services.
    – Exfiltration precedes encryption by ~10 days; therefore victims face dual extortion.
    – Ransom notes threaten GDPR fines to European victims, leveraging reputational risk to pressure faster payment.

Using these tactics, multiple organizations have recovered without paying ransom by accelerating fresh-image restores and patching three days post-in detection. Treat akgum with the same urgency as Conti, LockBit, or Akira—rapid containment, strong backups, and immediate credential reset tiers remain the most effective path.