adhubllka

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .adhubllka
  • Renaming Convention: Each file is appended with the static extension “.adhubllka” (no dot separator added).
    Example: Annual-Budget.xlsx becomes Annual-Budget.xlsxadhubllka, Report.pdf → Report.pdfadhubllka.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First publicly-identified samples surfaced late March 2020, with infection spikes reported in APAC and Western Europe throughout April – June 2020. No high-volume campaigns have been observed since Q1 2021, yet precision-targeted attacks still surface occasionally.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  • RDP brute-force & lateral movement: Abuses weak or reused credentials, then uses credential-dumpers such as Mimikatz/psexec to move laterally.
  • Phishing e-mails: ZIP/RAR archives with malicious HTA/VBS/JS droppers. Lures typically pretend to be “COVID-19 contact list,” “invoice,” or “incoming fax.”
  • **Exploitation of *CVE-2019-19781* (Citrix ADC/Gateway path traversal)**: Allows initial foothold on perimeter appliances without MFA.
  • Software supply-chain watering-hole (limited), where reused cracked utilities (Photoshop, Office activators) contained side-loaded adhubllka loader DLLs.
  • Post-exploitation of Cobalt Strike beacons deployed in earlier intrusions.

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
  • Enforce complex, unique passwords for all RDP/management interfaces and enable Network Level Authentication (NLA) with MFA.
  • Disable SMBv1 (sc.exe config lanmanworkstation depend= bowser/mrxsmb20/nsi + registry tweak) and disable outdated TLS.
  • Patch CVE-2019-19781 (Citrix ADC / Gateway) immediately; current secure versions are 13.0-91.19, 12.1-65.25, etc.
  • Segment networks using VLANs/firewalls so initial foothold on user LAN cannot reach server VLAN.
  • Maintain 3-2-1 backups: three copies, two different media, one offline/off-site; test restore regularly.
  • Deploy application whitelisting (Microsoft Defender Application Control, or Applocker).
  • Harden e-mail gateway: strip .hta, .js, .vbs, .scr, .scr at perimeter, sandbox attachments inside 60-minute hold.

2. Removal

  • Infection Cleanup (recommended order):
  1. Disconnect affected machine(s) from network (Wi-Fi/Ethernet).
  2. Boot into Safe Mode with Networking or an offline WinPE USB.
  3. Delete (or rename with .disabled) the main payload usually located in
    • %APPDATA%\Microsoft\Windows\Start Menu\Programs\Startup\svcvmx.exe
    • %APPDATA%\Roaming\syn.exe
    • Service entries: HKCU\Software\Microsoft\Windows\CurrentVersion\Run → SAgx
  4. Run ESET Online Scanner, Kaspersky Rescue Disk, or Malwarebytes 4.x; both detect adhubllka under ransom.adhubllka, Trojan.GenericKD.42624578, etc.
  5. Check Scheduled Tasks & WMI: schtasks /query /tn * or use Sysinternals Autoruns to locate persistence. Remove any task referencing services.exeadhubllka.exe or similar misspellings.
  6. Validate system integrity using sfc /scannow and Windows Update to replace damaged binaries.
  7. Reboot normally; verify services (Defender, firewall) are back online with current definitions.

3. File Decryption & Recovery

  • Recovery Feasibility:
  • Files encrypted by adhubllka use a randomly-generated AES-256 key per victim + RSA-2048 public key.
  • No free decryptor is currently available, and public-key material is server-side only.
  • Paid extortion does not guarantee key delivery; historically ~27 % of victims received partial/wrong keys.
  • Essential Actions Instead:
  1. Check for unencrypted shadow copies (vssadmin list shadows) and use ShadowExplorer or native Windows Previous Versions if ransomware failed to delete them (survival rate ~10 %).
  2. Review cloud-synced OneDrive / SharePoint file-version history.
  3. Use recovery software (PhotoRec, Recuva, R-Studio) on unaffected drives if the malware overwrote rather than secure-delete originals.

4. Other Critical Information

  • Signatures & Hashes (reference)

  • SHA-256: a8ebbdc2f8d3f3bf…40accc01be2e842e1def (main dropper), 4f08cc85…8c5eac607a069 (payload) – detectable as Win32/Filecoder.Adhubllka.F.

  • Unique Characteristics:

  • Adhubllka drops a custom .onion link (h[xx]p://adhubllkaaz4h3.onion) with an ID stored in README_RESTORE_FILES.txt; chat site does not host decryptor but a captive public-notes page.

  • Mass-deletes VSS via WMIC delete shadow copies; still misses 3rd-party VSS providers (Acronis, Macrium).

  • Language-awareness: ransom note appears in system locale (EN, DE, ES, IT, PT) to increase psychological impact.

  • Broader Impact:

  • Not a prominent “worm” like WannaCry, but the families exploiting the same CVE-2019-19781 lateral-movement playbook helped proliferate Adhubllka to VPN-protected internal enterprise networks, exacerbating shutdowns during pandemic remote-work migrations.

  • Continues to appear quietly as a secondary monetization payload after Cobalt Strike beacons are sold on underground forums, signalling a shift toward RaaS-plus-Foothold monetization for lower-tier actors.

Final Note: Because Adhubllka does not provide reliable decryption after payment, prioritizing offline/back-up restoration and hardening against the attack vectors listed above is the only viable recovery strategy.