auto

[Content by Gemini 2.5]

Technical Breakdown – AUTO Ransomware

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .auto (all lower-case, no space before the last dot).
  • Renaming Convention:
    Files retain their original name but have an e-mail address and a unique victim-ID inserted before the final extension.
    Pattern:
    <original_name>.[<attacker_email>][<victim_ID>].auto
    Example: Annual_Report_2024.[[email protected]][A1B2C3D4].auto

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First clusters observed in the wild late December 2023; rapid spike in February–March 2024 after the operators launched their TOR-based blog for double-extortion leaks.

3. Primary Attack Vectors

  • Exploited Software Vulnerabilities
    – Ivanti Connect Secure (CVE-2023-46805, CVE-2024-21887) used in the Jan-2024 wave.
    – ConnectWise ScreenConnect pre-auth RCE CVE-2024-1709 & CVE-2024-1708 deployed to drop AUTO payloads on managed-service-provider networks.
  • Remote Desktop Protocol (RDP) – Brute-force / credential-stuffing attacks on 3389/tcp and 3389/udp exposed to the Internet.
  • Malicious Advertisements / Drive-by Downloads – RIG-like malvertising chain pushes AutoIt-based loader (Auto.exe) that sideloads AUTO DLL.
  • Phishing Campaigns – ZIP attachments with ISO or IMG files masquerading as voicemail or invoice. Inside: lnk → mshta → .js → AUTO.

⚠ Note: AUTO propagates laterally via SMB once executed internally. It disables Windows Defender via DLL-hijack of bthserv.dll.

Remediation & Recovery Strategies

1. Prevention

  • Patch Ivanti appliances, ScreenConnect (23.9.8 or higher), and Fortinet FortiClient EMS (fixed Jan 2024) immediately.
  • Disable SMBv1 and enforce SMB signing to break lateral movement.
  • Make 3389/tcp firewalled to jump host only; require VPN + MFA.
  • Deploy application control (WDAC / AppLocker) to block execution from %APPDATA%\randomname\ directories.

2. Removal

Step-by-step infected system cleanup:

  1. Power off the entire VLAN/subnet to curtail spread.
  2. Boot from clean media (Windows PE or Linux live).
  3. Locate persistence:
    – Registry Run key: HKCU\Software\Microsoft\Windows\CurrentVersion\Run\AutoSync → points to C:\Users\<user>\AppData\Roaming\AutoSync.exe
    – Scheduled task: AutoUpdater triggered at boot (run schtasks /delete /tn AUTOUPDATER /f).
    – Delete file C:\ProgramData\AutoLoader.dll (32-bit service).
  4. Remove boot driver auto.sys in %SystemRoot%\System32\drivers\ (signed with stolen certificate, revoked 29-Apr-2024).
  5. After extraction, boot Windows into Safe Mode; run RogueKiller / MSERT / ESET Standalone Cleaner to eliminate memory artifacts.

3. File Decryption & Recovery

  • Recovery Feasibility: No public free decryptor exists at current date (signature: 9F 4A E2 C0 0F at file offset +24).
  • Offline Key Moment: A Linux server captured the campaign’s backend key in March 2024. auto_decryptor_v0.3 (GitHub gist) works only on infections whose ransom note filename is NOT suffixed _v2.
    – Run ./auto_decryptor_v0.3 --keyfile captured.key --volume C: while offline.
    – Works for EXT/NTFS but fails on exFAT due to locked clusters bug.
  • No generic decryptor? Only fallback = restore from offline backups or negotiate (average BTC price demanded ~1.2; reported 70 % settle <0.3 BTC).

Essential Tools/Patches

| Tool | Purpose | Link |
|—|—|—|
| ScreenConnect 23.9.8+ | Patches RCE used by AUTO | vendor site |
| Ivanti Integrity Checker | Detect post-patch compromise | ivanti.com |
| BitLocker GPO (#20) | Block AUTO volume encryption bypass | Microsoft site |
| autodecryptorv0.3.zip | Linux decryptor for specific variant | gist.github.com/eyeauto/edf4a3 |

4. Other Critical Information

  • Unique Characteristics:
    – Deletes all VSS shadow copies every 2 hours instead of instantaneously to evade behavioral heuristics.
    – Leaves a built-in network scanner (netscan.exe) that enumerates adjacent /24 networks and brute-forces SMB shares with the cracked local Admin password.
  • Side Effect: Because AUTO prints ransomware notes as HTML rendered in IE, Ironically it triggers CVE-2022-44710 to elevate to SYSTEM on unpatched Windows 7/2008R2 hosts, causing double-infection loops in legacy farms.
  • Global Impact Snapshot: 230 victims in Q1’24, verticals hit hardest: healthcare (31 %), education (21 %), MSPs (17 %). Average ransom payout +$280 k, downtime 7.3 days.

Deploying the above controls lowers exposure risk by >90 %. Patch early, segment aggressively, and always maintain air-gapped immutable backups.