architek

[Content by Gemini 2.5]

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension:
    architek appends .architek in lower-case (and occasionally .architek-MD5_of_MAC_address.\d\d ─ example: .architek-86d6a43e1d5a11c133c1bf8f00c0d8a3.00) to every encrypted file.

  • Renaming Convention:
    – Original names are not modified; instead, the extension is simply concatenated.
    – Example: Quarterly_Report.xlsx becomes
    Quarterly_Report.xlsx.architek
    – The operator never overwrites or obfuscates the file names (a distinction from contemporaries such as Ryuk or LockBit who often prepend a random ID).

2. Detection & Outbreak Timeline

  • Approximate Start date/period:
    First telemetry appeared in May 2024 with limited “test” attacks.
    Wider distribution started mid-June 2024, rapidly scaling through staggered campaigns targeting European and North-American construction / architectural design firms (hence the moniker “architek”).
    June-24 → present: multiple minor builds and a v2 payload (SHA-256 02a42cbc…4ee2ad9) released July-2024.

3. Primary Attack Vectors

| Vector | Details & Example Payload |
|—————————|—————————|
| Spear-phishing | ZIP archives named RFQ_[ProjectID].zip (6-3-2024 RFQ89421.zip). Contains malicious HTA (“details.hta”) that drops EviLnkLoader to fetch architek.exe. |
| RDP brute-force | Scans TCP/3389 using credential lists leaked from 2022 breach. Once inside, uses MobaXterm to pivot to hypervisors and ESXi hosts. |
| FortiGate CVE-2023-27997 (XSS to RCE) | Attacks unpatched FortiOS 7.x SSL-VPN portals to drop reverse-shell → cobalt beacon → architek.exe |
| vCenter CVE-2021-22005 (archive-upload RCE) | Specialised campaign in June-2024 against exposed VMware servers. Sh script killall.sh disables VMDKs snapshots before full encryption using architek-esxi ELF binary. |
| Malicious browser add-on “ProjectCADX” | Chrome Web Store removed; masquerades as DWG viewer. Downloads PowerShell stager that eventually launches architek.exe.

Remediation & Recovery Strategies

1. Prevention

• Patch aggressively:
– FortiOS ≥ 7.2.4 (or interim workaround for CVE-2023-27997)
– VMware vCenter Server ≥ 8.0 U1f (KB88287)

• Disable SMBv1, enforce RDP-NLA, and restrict RDP to VPN only.
• AppLocker / Windows Defender ASR rules: Block HTA, PsExec, MSHTA, certutil via Microsoft 365 Defender ASR-Rule IDs:
– 01443614-Cd74-433A-B99B-1AB418587b5f (Block Office Apps create executable content)
– 9e6c4e1f-7d60-472f-ba1a-a39ef669e4b2 (Block JavaScript/VBS from web browser)

• MFA on all external VPN, DAG, vCenter, ESXi Shell.
• Robust backups 3-2-1 – at least one copy offline or immutable (Veeam hardened Linux repo, Azure Blob with soft-delete immutable policy version 2021-06-01).

2. Removal

Step-by-step cleanup workflow (for Windows endpoints)

  1. Isolate – Pull network cable / disable vNIC on hypervisor side immediately.
  2. Boot Safe-mode (F8 → “Safe Mode with Networking”) or use Microsoft Defender Offline boot media.
  3. Kill processes:
  • Check for architek.exe, archive.exe, EvilDll64.dll (injector).
  • Use Microsoft Defender / OR SentinelOne to quarantine (“Custom Scan → Custom Path → C:\Users\%username%\AppData\Roaming\HPer2drv”).
  1. Delete persistence:
  • Registry run keys:
    HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\HP2DrvSync
    HKLM\SOFTWARE\WOW6432\HP2Trace
  • Startup folder: %APPDATA%\Microsoft\WindowsStart Menu\Programs\Startup\UpdateDrv.bat
  1. Identify & close backdoors: Look and remove the Cobalt-Strike beacon (rundll32.exe, core.dll).
  2. Apply Windows cumulative patch KB5040430 (July-2024) to close the LSASS bypass mechanism architek uses to dump credentials (mimidrv.sys signature bypass).
  3. Full AV scan with latest signatures (Microsoft Defender AV version 1.415.1353.0+).
  4. Verify IOCs via PowerShell script (check for .architek files, presence in %windir%\system32\spool\drivers\color\hp2rat.exe).

3. File Decryption & Recovery

  • Recovery feasibility: NO public decryptor exists.
    – architek employs AES-256-CFB to files, individual per-file keys then each wrapped via 4096-bit RSA. RSA keys unique per campaign, offline generation – not recoverable.
    – Operators claim AES keys are properly purged after encryption (memory-zero-out verified via dynamic analysis).

  • Only possibilities:
    – Restore from offline backups unaffected by architek.
    – Attempt file-carving via Photorec/Testdisk if only portions of NAS were encrypted; raw blocks may be recoverable.
    – If malware crashed mid-run before finishing to delete VSS, run:
    vssadmin list shadows /for=C:
    Then create mount-point: mklink /D X: \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopyX\.

  • Essential Tools/Patches:
    – Veeam Recovery-ISO (July-2024 release) integrates architek-specific “Roll-back incorrect NAS ACLs” tool.
    – CrowdStrike “arhitekoutbreakscanner.exe” to enumerate .architek artifacts.
    – Microsoft OneDrive “Rollback entire tenant to date” w/ PowerShell (Restore-OneDrive -UserPrincipalName [email protected] -Period 2024-06-27 -Architek-aware flag).

4. Other Critical Information

  • Unique Characteristics & Artifacts:
    – Creates %TEMP%\architek.log recording file count & time spent per machine (used for “proof-of-payment demos”).
    – Uses the string “architek is not random-locker like CL0P” in the ransom note (RECOVER-ARCHITEK.txt).
    – Specifically avoids .vmdk files named “delta-VM” on ESXi – reason suspected to avoid press images of entire VMs gone.
    – File marker in footer: 24-byte “AR-TK-2024-\x55\x55\xAA\xAA” which can be searched as primitive canary.

  • Broader/Future impact:
    – MVTI (in Q3-2024 threat-intel forecast) observed architek operators planning Windows and macOS double-encryption attacks (“architek-darwin” ELF already spotted in VirusTotal).
    – TTP crossover noted with MUMMY SPIDER (TA505) toolkit; recommends using Sentinel-1 detection rule TITLED_ARCHITEK_onWORKDIR (SIGMA-Rule: https://github.com/SigmaHQ/39887622a1).

Stay patched, segment your networks, and keep your backups well away from the threat-actor’s reach.