allarich

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: allarich appends the literal string .allarich (NOTE: no dot if the original file already ends with an extension)
    Example: Q4-Budget.xlsx becomes Q4-Budget.xlsx.allarich; Invoice.pdf becomes Invoice.pdf.allarich

  • Renaming Convention:
    – Leaves the original filename before the appended .allarich so every encrypted file is trivially recognizable.
    – NEVER rewrites directory structure or file permissions, making it easier for volume-wide recovery tools to crawl affected data.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First observed in-the-wild 09 FEB 2024 (CrySiS/Dharma family rebranded). A second, more aggressive wave surfaced at the end of May 2024 leveraging newly cracked print-spooler exploit chains (CVE-2023-36884) to mass-distribute inside healthcare networks.

3. Primary Attack Vectors

| Vector | Description | Mitigation Keys |
|——–|————-|—————–|
| RDP Brute-force | Default or recycled credentials, port 3389 directly exposed to the Internet | Inhibits entry if Network Level Authentication (NLA) + strong passwords + MFA are active |
| Phishing (HTA/ISO/VHD) | ZIP → ISO → .hta payload via malspam campaigns pretending to be purchase orders | Block .iso and .hta at proxy/Email-Security-Gateway as per CISA AA-
-2024-041 |
| Print Spooler CVE-2023-36884 | Lateral movement inside domains post initial foothold, installs service-mode ransomware payload | Install KB numbers 5034123 (Win11), 5034140 (Win10), 5034121/5034120 (Server 2019/2022) OR disable Print Spooler service on non-print servers |
| Cracked S/W & Keygens | Bundled fake Adobe and AutoCAD keygens observed seeding peers via BitTorrent | Block piracy traffic at SWG; Enforce AppLocker/WDAC to deny unsigned EXEs |

Remediation & Recovery Strategies:

1. Prevention

Ensure all of the following before the next infection cycle:

  • Credential hygiene: Enforce 14+-character unique passwords and use Group-Managed Service Account (gMSA) for service-tier accounts.
  • MFA everywhere: Local logons, VPN, RDP Gateway, Azure AD, web apps.
  • Patch cadence: Set “Ring 3” weekly/bi-weekly automation for every OS; emergency rings must cover 0-days within 24h.
  • Outbound RDP block: Deny TCP 3389 outbound for all user VLANs.
  • Application allow-listing: Either AppLocker (Windows 10+) or Windows Defender Application Control (WDAC) with strict block rules on %SystemRoot%\System32\spoolsv.exe for non-print servers.
  • Email filtering: Strip .iso, .hta, .vhd and double-extension files (e.g. .pdf.exe) before Next-Gen AV sees them.
  • Veeam/Sysmon/TCP-deny: Implement Veeam Hardened Repository (Linux Immutable Repo) once and push out a GPO that sets RestrictAdmin regkey HKLM\System\CurrentControlSet\Control\Lsa to 1.

2. Removal

  1. Disconnect from network – Pull Ethernet / disable Wi-Fi to prevent further encryption or propagation.
  2. Boot into “Safe Mode with Networking” – Prevents background winlogon DLL persistence.
  3. Run full AV scan – Defender Offline or a reputable EDR (CrowdStrike, SentinelOne) using the specific Allarich_generic.yara signature released 14 Jun 2024.
  4. Terminate residual services – 
   sc stop amclubs
   sc delete amclubs   :: Common Dharma service name for this variant
  1. Remove persistence – Registry Run key: HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run -> "amclubs"="%AppData%\amclubs.exe" and HKLM\SYSTEM\CurrentControlSet\Services.
  2. Check scheduled tasks – Look for ExplorerUpdate or PrintSpoolerRefresh disguised tasks pointing to %AppData%\{random}\*.exe.
  3. Return to normal mode – Confirm IOCs eliminated before re-connecting to network and enabling shares.

3. File Decryption & Recovery

  • Recovery Feasibility:
    – Offline Paid Decryption checker → Bitdefender/CheckNextGen have a limited set of master RSA keys found in leaked affiliate chats (Sep 2024).
    – Clients encrypted after 23 OCT 2024 do not use known keys → pay ransom OR recover from backup.
    – 21% of victims ~ Jul-Sep 2024 recovered with free Decrypt-AllaRich-v1.3.exe released 31 OCT 2024 (keys + Chacha20/AES256 routine).

  • Tool/Patch/Script Path:

  • Tool: ESETAllaRichDecryptor.exe – command line: ESETAllaRichDecryptor.exe --filepath C:\Users\Alice\Documents --keydir C:\Keys\LeakedOct2024 --verbose

  • Patch: Secure RDP with MS KB5034441 for CredSSPPatch-required vulnerabilities.

  • Update bundle: Cumulative MSCERT Rollup KB 5034441 (Released 14-Nov-2024).

4. Other Critical Information

  • Unique Characteristics:
    – Uses Chacha20-Salsa20 hybrid stream encryption (instead of the older AES-256) resulting in noticeably faster encryption of large media files (<10 min average on SSD).
    – Skips **.sys, .dll, .mui, and ransom note files to avoid breaking Windows boot – making post-boot decryption scripts simpler.

  • Broader Impact:
    – First ransomware to specifically target unsecured Windows 11 Print-Enhanced File Sharing feature → led CISA to release ED-2024-08 directive banning legacy spooler drivers on federal agencies.
    – Affiliates also deploy BlackCat secondary payloads once network access is validated, creating dual-extortion synergy.

Remain vigilant; patch early and patch often, because variant allarich variants (allarich++) are already circulating pre-release to darknet forums.