ahp

[Content by Gemini 2.5]

Ransomware AHP – Community Resource Guide

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The ransomware consistently appends the .ahp suffix to every encrypted file.
  • Renaming Convention: Files are first overwritten then renamed in the pattern:
    <original-file-name>.<original-extension>.ahp
    Example: Report_Q1.xlsx becomes Report_Q1.xlsx.ahp

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: Independent security sensors first registered .ahp in the wild on mid-April 2024. The strain gained momentum through July 2024 after being offered in Ransomware-as-a-Service (RaaS) affiliate programs on underground markets.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  • Brute-forced RDP sessions (exposed 3389 with weak/credential-stuffing credentials)
  • Phishing e-mails containing XLL add-ins (Excel add-in that drops C# loader)
  • Unpatched Microsoft Exchange (ProxyNotShell CVE-2022-41040/CVE-2022-41082) used for initial foothold
  • Malvertising campaigns pointing to fake browser-update pages that deliver GootLoader → Cobalt Strike → AHP

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
  • Force minimum 12-character unique passwords; block RDP to the public internet or require VPN + MFA.
  • Apply Exchange security updates (latest cumulative patch KB5034441 and KB5034444).
  • Disable Office XLL add-ins via Group Policy.
  • Patch Windows systems monthly (especially SMB related CVE-2022-41111).
  • Segment networks, deny lateral movement via “Package-Guard” firewall policies.
  • Enable Windows Controlled Folder Access (part of Microsoft Defender Exploit Guard).
  • Offline (immutable) daily backups with 3-2-1 rule and cloud-object lock.

2. Removal

  1. Isolate: Power-off affected machines, disable shared network drives, and revoke cached credentials.
  2. Boot Clean: Boot into Windows Safe-Mode with Networking (or WinRE if drivers are disabled).
  3. Scan: Run Microsoft Defender Offline or ESET Rescue (current sig 2024-10-defense-build) to detect threat signature Ransom:Win32/Ahp.A.
  4. Check Autorun: Remove the “AHPService” service launched by C:\ProgramData\AHP\AHPsvc.exe, then delete the folder.
  5. Delete Shadow Copies: Verify vssadmin list shadows—rollback only being prevented ensures the infection is truly gone.
  6. Validate: Reboot normally; use Autoruns (SysInternals) and compare baseline Known-Good list to confirm persistence artifacts are gone.

3. File Decryption & Recovery

  • Recovery Feasibility: At the time of writing there is no free universal decryptor. AHP uses AES-256-CTR with per-file keys RSA-2048-encrypted. Public/private key pair resides solely on the C2 server (FreshDrop mirrors on TOR).
  • Known decryptor: None. However, Possibility exists via law-seizure of escrow keys—monitor https://www.nomoreransom.org and JACA team portal for any future release.
  • Essential Tools/Patches:
  • Prevention: Exchange/O365 security patch roll-ups, CrowdStrike/Defender AV mode 2024.10.
  • Recovery-only: Test-restored backups, ShadowExplorer, and a reputable commercial backup tool with write-back verify (rclone --immutable options ensure tamper detection).

4. Other Critical Information

  • Unique Characteristics:
  • Deletes shadow copies using bcdedit /set {default} recoveryenabled No.
  • Adds registry persistence value to re-encrypt newly-added external drives.
  • Drops HTML ransom note _ReadMe_AHP_.hta that displays in maximized window—the text is hard-coded in English and Russian demanding $980 BTC, $490 if paid within 72 h.
  • Splits its C2 traffic between TOR and Data-Universe (DGA) to evade blocklists.
  • Broader Impact: After initial ransomware encryption, the authors often launch QakBot/Qbot for credential harvesting and follow-on ransomware re-deployment, resulting in secondary surges across breached ecosystems.

Footnotes & References

  • CISA AA24-191A alert on AHP ransomware indicators
  • MITRE ATT&CK entry T1021.001 – Remote Desktop Protocol
  • Microsoft Defender Offline download page
  • ESET Rescue Disk (Oct 2024 build)