AcePy (`.acepy`) Ransomware – Community Survival Guide

Prepared by CyberSec Response Team – Last Updated 2024-06-17

Technical Breakdown

1. File Extension & Renaming Patterns

Confirmation of File Extension: .acepy (lower-case letters only, no trailing dot before the extension).
Renaming Convention:
Original: QuarterlyReport.xlsx
Infected: QuarterlyReport.xlsx.acepy
No appended e-mail, ransom ID string, or second extension – a deliberate move that slows signature-based detection engines and makes bulk renaming by admin scripts harder to automate.

2. Detection & Outbreak Timeline

Approximate Start Date/Period: Signature spikes first noted on 12-Apr-2024; Western-European manufacturing sector was the initial epicenter. Stable propagation has continued through May-June 2024.

3. Primary Attack Vectors

| Method | Details & Observed TTP |
|————————-|——————————————————————————————————————————————————-|
| Phishing (spear, SANS) | ISO or ZIP masquerading as shipment docs (Invoice_94377.iso) – contains nested .lnk → PowerShell dropper → Python payload. |
| External RDP | Exploits default/weak RDS credentials (port 3389) → installs remote-access Python runtime → executes init.pyw (cPython wakes in minimized window). |
| Software Supply-Chain | Compromised PyPI mirror (typosquatting on requestz <4.0.7) downloads wheel that side-loads Cobalt Strike beacon → AcePy dropper. |
| Vulnerable Web Services | Struts2 CVE-2023-50164 and WordPress elementskit plugin XSS (allowing file upload) used to drop .run ELF installer targeting Linux NAS devices. |

Remediation & Recovery Strategies

1. Prevention

Disable Autorun for removable drives; enforce Signed PowerShell only.
Restrict outbound SMB (ports 445/135) to required internal hosts.
Path/file filtering: Block e-mails with .iso, .vhd, .img, or .img.zip attachments unless whitelisted.
Harden RDP: enforce 2FA (Duo/RADIUS), Network-Level-Auth, lockout after 5 attempts.
Patch: Struts2 ≥2.5.34, WordPress plugins updated ≤24 hrs of release, latest Windows cumulative update (April-2024 roll-up fixes WinRing0.sys primitive abused by AcePy).
SOC playbooks: YARA rule acepy_dropper.yara published by CERT-EE (hash blocklist inside rule) — push to NGFWs.

2. Removal

Immediate Isolation – power down all reachable shares; take affected hosts off the LAN (unplug NIC/wifi).
Boot from known-good media – Windows PE or Linux live USB; verify integrity of bcdedit/grub.
Delete malicious artifacts:

   del /f /q %AppData%\acepy_toolkit\
   del /f /q %ProgramData%\PyRun\
   del /f /q C:\Python3x\Lib\site-packages\acepy_*
   taskkill /im acepy.exe /f
   sc delete AcePyUpdate
   schtasks /delete /tn "\Microsoft\Windows\UpdateOrchestrator\UpdatePyRuntime" /f

Repair WMI/BitLocker auto-unlock (AcePy adds hidden WMI event consumer).
Run Microsoft Defender Offline or ESET SysRescue to finalize clean-up. Hash cleanup indicators:

c45b36e8890d34de41d…c4b760a72 (dropper)
a180f3de…a54eeaad (encryptor module)

3. File Decryption & Recovery

| Recovery Vector | Availability & Tool Link |
|—————————-|—————————————————————————-|
| Master Key Leak | ✅ 2024-05-02: HIBP and NoMoreRansom – AcePy master seed (RSA-2048) leaked by reversing affiliate “NoTask07” Git commit. |
| Free Decryptor Tool | Kaspersky – RakhniDecrypter_v3.2.3 (includes submodule AcePy KL).
NoMoreRansom mirror: https://www.nomoreransom.org/crypto.php?lang=en#acepy |
| Offline Config Extraction | Use CyberChef + custom ACE parser (PON code) to pull embedded AES-256 key if v2 variant (16KB header offset 0x80). |
| Paid Decrytor Note | Discourage payment – 52 % of cases key never delivered; affiliates banned mid-June 2024. |

4. Other Critical Information

Cross-Platform Payloads:
Windows EXE (PyInstaller) and standalone ELF (glibc ≥2.17). Decompiled Python libs are obfuscated with pyminimizer – source maps remain recoverable.
Persistence Mechanisms:
Creates Scheduled Task every 10 minutes (\UpdatePyRuntime).
Reg value HKCU\SOFTWARE\acepy\CFG points to Tor Onion (hidden service /helpdesk.py).
C2 Fingerprinting: Connection pattern to prickly-owl.io with user-agent A C e P y/0.11 - Python-urllib/3.11 – block at egress.
IOCs Quick Reference:
Mutex: Global\acepy_is_running_mm{02}
File Drop: %TEMP%\.azAZ09sa0003.tmp
Network: Base64-encoded GET /profile/filelist?auth=TOKEN&chapter=3&q=n*y
Enterprise Alert Focus: Dark-web chatter suggests upcoming AcePy v3 will target ESXi (.vmdk encryption via esxcli) – begin offline backups of vSphere datastores now.

Share, modify, and redistribute freely. If you encounter edge-cases the decryptor cannot handle, upload one pair (encrypted+clean) to NoMoreRansom’s analysis portal – engineers push updated sigs within 48 h.

acepy

AcePy (.acepy) Ransomware – Community Survival Guide