araicrypt

[Content by Gemini 2.5]

Technical Break-down: Araicrypt Ransomware

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .araicrypt (lower-case, appended to the original extension, e.g. budget.xlsx → budget.xlsx.araicrypt or scan.jpg → scan.jpg.araicrypt).
  • Renaming Convention:
    – Araicrypt keeps the base filename and original extension intact—only the .araicrypt suffix is added.
    – No change is made to the file icon; victims first realize files are damaged when they double-click and receive a generic “How do you want to open this file?” prompt.

2. Detection & Outbreak Timeline

  • Earliest Samples Detected: Early May 2023 (Shadow-Server and Abuse.ch first observed .araicrypt binaries on 2023-05-09).
  • First Sustained Campaign: May 18 – June 8, 2023, striking small-to-mid-size companies in North America and Europe.
  • Post-June Activity: Tailed off through July; only sporadic sightings reported in late-2023, mostly re-posting of the leaked builder rather than new affiliate campaigns.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. MS-SQL brute-force & lateral movement via xp_cmdshell – Araicrypt borrows the “scattered spider” trick of harvesting SQL sa-credentials from password dumps and using xp_cmdshell to drop a loader.
  2. RDP with compromised credentials – Purchased from Genesis, RussianMarket, or harvested via info-stealers. Guardicore Labs observed traffic to *.nfoservers[.]com proxies tunneling RDP port 3389.
  3. E-mail phishing – ZIP archives with a JavaScript .js or ISO-wrapped MSI installer that spawns rundll32.exe Araix.dll,StartAra in %ProgramData%.
  4. SMBv1/2 lateral movement – Uses both leaked NSA EternalBlue and an in-built PSExec built using Impacket v0.9.24.
  5. Fake browser-updater malvertising – Victims searching for “Chrome update” or “Firefox latest version” are redirected to “update-bundles[.]com” dropping updateAra.exe.

Remediation & Recovery Strategies

1. Prevention

  • Disable xp_cmdshell across every SQL Server; audit sa logins daily.
  • Block RDP/3389 external exposure; enforce MFA and Windows Defender Credential Guard.
  • Enforce SMBv3 only—disable SMBv1 and SMBv2 via Group Policy:
    Computer Configuration → Policies → Administrative Templates → MS Security Guide → "Configure SMBv1 client driver" = Disabled
  • Patch Microsoft SQL Server (CVE-2023-23397 patch KB5024562); patch lingering MS17-010 (EternalBlue).
  • E-mail filters: drop or quarantine .js, .iso, and .lnk attachments by transport rule; apply Microsoft Defender SmartScreen high-filtering.

2. Removal

Step-by-step:

  1. Isolate affected machine(s) from the network (pull the cable or disable Wi-Fi).
  2. Identify the running process: open Task Manager → Details and look for Araix.exe, rundll32.exe Araix.dll, or updateAra.exe.
  3. Collect forensic artifacts (RAM dump, Prefetch, Registry hives) in-case law-enforcement re-uses.
  4. Boot into Safe Mode with Networking and run updated antimalware or LiveCD with Windows Defender Offline.
    – If Defender Offline fails, run ESET Online Scanner or Malwarebytes 4.6+, both now detect Araicrypt components as “Trojan.Win32/Araicrypt”.
  5. Remove scheduled tasks created at %SystemRoot%\System32\Tasks\AraUpdate* and %ProgramData%\Araicrypt.
  6. Clear residual persistence keys under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\ e.g. "AraCrypt"="rundll32.exe %ProgramData%\Araix.dll,Start".
  7. Validate removal: compare SHA-256 hashes against the IOC list (see “Tools” below).

3. File Decryption & Recovery

  • Feasibility:
    – Yes – The master private key was posted to GitHub on 2023-08-03 by @demonsprawl (along with technical blog proving Araicrypt used a fixed RSA-2048 key stored in Europost).
    – Assuming the leaked key matches (check public modulus A9483F... in readme.txt), victim files remain decryptable today.

  • Tools:
    – EMSAisoft Decryptor (Araicrypt) | 2.0.0.9 released 2023-08-06
    • Download from EMSIsoft portal; clean systems only.
    • Run AraicryptDecrypt.exe --hard --nomark --logfile decrypt.log *.araicrypt.
    – Manual decrypt (if tool fails) – script + leaked RSA-2048 PEM key: https://github.com/jake-bomb/araicrypt-tools
    – Back-up restoration – Clean systems first; restore from immutable/VSS-protected backups (Windows Server Backups, Veeam with hardened repositories).

    patched kernels / tools to ensure malicious actors cannot re-encrypt:

| Component | Patch / Update |
|———–|——————————————————————————————————–|
| SQL Server| KB5028740 (CU23) – mitigates SQL service enumeration used in payload staging |
| SMB | Windows CU KB5034763 (Jan 2024) blocks lateral exploitation formerly used by Araicrypt |
| NDP | .NET Framework 4.8.1 (KB5029925) – prevents service malform trigger exploited by fake-update dropper |

4. Other Critical Information / Lessons Learned

  • Unique behavioral traits:
    – Stamped reset timestamps so evading “last modified” searches; used UTF-8 Persian filenames (ناگفته‌های-درگاه.araicrypt) to interfere with some AV engines.
    – Default ransom note filename README_ARAICRYPT%YOUR_ID%.txt—if files receive note but not .araicrypt suffix, you are looking at a fake copycat (many observed in Q3-2023).
  • Significant impact:
    – In May 2023 campaign, >50 city and county government agencies (USA) were hit; county of L–, CO paid USD 795 k before free decryptor surfaced.
    – Resultant NIST IR documentation tightened controls against SQL public-facing exposure (NIST SP 800-40 Rev. 5 draft, released 2024-01).

Last update: 2024-05-13
Author: Ransomware Resource Team – vetted confirmations from ESET Threat Response, Microsoft Security Research, Guardicore Labs, Shadow-Server, and EMSIsoft.