adobe

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The malware appends the .adobe extension to every encrypted file (e.g., Report.xlsx → Report.xlsx.adobe).
  • Renaming Convention: An additional unique identifier (typically 5–8 hexadecimal characters plus a campaign ID) is inserted before the extension, resulting in the pattern:
    <original_filename>.id-<[A-F0-9]{5,8}>.[<attacker_email>].adobe
    Example: [email protected]

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First telemetry samples date back to late November 2018 with a marked surge in March–April 2019 after the criminals behind STOP (Djvu) updated their affiliate kit.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Software “cracks” and keygens masquerading as Adobe Photoshop, Premiere, Office 2019, etc. (most common).
  2. Malvertising via pop-under ads redirecting to fake update pages (FlashPlayer_Update_#<random>.exe).
  3. Exploitation of weak RDP credentials, then hands-on deployment to mapped drives.
  4. Bundled with Potentially Unwanted Applications (PUAs) in third-party repackagers (e.g., PatchMyPC-wannabes).
  5. File-sharing networks (e-sports game repacks, music torrents).

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
  • Block outbound SMB at the perimeter; enforce SMB signing everywhere.
  • Deprecate/Disable SMBv1 via Group Policy (Disable-WindowsOptionalFeature ‑Online ‑FeatureName SMB1Protocol).
  • Enforce least-privilege local admin rights; restrict PowerShell via Constrained Language Mode.
  • Patch common exploited applications monthly: Java, Flash, Office, Adobe Reader.
  • End-user training: Instruct users to never run cracks or unofficial software patches—the majority of .adobe infections stem from these vectors.
  • Host-level protections: Deploy reputable AV/EDR with behavioral protection (Microsoft Defender link in offline mode, SentinelOne, Kaspersky, Bitdefender).
  • AppLocker / Windows Defender Application Control (WDAC) policy to block unsigned executables outside C:\Windows or whitelisted paths.

2. Removal

  • Infection Cleanup (Windows-only; subsequent steps):
  1. Isolate the host: Unplug network or disable Wi-Fi; stop lateral spread.
  2. Boot into Windows Safe Mode with Networking (or WinRE if Safe Mode unavailable).
  3. Scan & remove:
    • Use ESET Online Scanner, Malwarebytes, or emergency antimalware ISO (e.g., Bitdefender Rescue CD).
    • Leverage Microsoft Defender Offline (run MpCmdRun.exe ‑Scan ‑ScanType 3 ‑File on mounted volumes).
  4. Verify persistence cleanup:
    • Delete registry keys: HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run entries referencing random-named binaries (e.g., C:\Users\Public\htrn1.exe) and the value SysHelper (if STOP variant).
    • Inspect Task Scheduler for tasks with misleading Microsoft-like names (OneDrive Update, Adobe Flash Scheduled Task).
  5. Re-enable controlled folder access & Windows firewall (they are sometimes silently disabled by the malware).
  6. Routine reboot and secondary scan to confirm signatures have been replaced (no reinfection).

3. File Decryption & Recovery

  • Recovery Feasibility:
  • STOPDecrypter is no longer maintained; use the community-supported Emsisoft Decryptor for STOP Djvu (2024 v1.0.0.239+).
  • Decryption is possible only if the campaign used an OFFLINE key.
  • Check the ransom note (_readme.txt) line:

    key – <key_string>
    mode – offline

    If the file reads mode – online, decryption relies on the private RSA master key that attackers keep on their server—currently irrecoverable.
  • Essential Tools/Patches:
  • Emsisoft STOP Djvu Decryptor (download directly from blog.emsisoft.com/decrypt-stop-djvu).
  • Kaspersky RannohDecryptor in edge cases to recover CS project files.
  • March 2020 Windows cumulative update closes a few chained Djvu CVEs. Always update to latest CU for your OS build (currently Windows 10 22H2 / Windows 11 23H2).

4. Other Critical Information

  • Unique Characteristics:
  • The dropper bundles Osiris stealer modules, siphoning browser passwords & credit cards before encryption—a key reason incident responders treat .adobe infections as data-breach events.
  • Adds Windows Defender Exclusions under %LOCALAPPDATA%\Local\Microsoft\Windows Defender\Scans\Exclusions—post-cleanup scans must explicitly re-scan those folders.
  • Writes a .bat file (c:\_readme.tmp) to unlock volume shadow copies for deletion, so pre-execution snapshots using a backup monolith (Veeam, Commvault) remain intact if the backup repository has immutable options.
  • Broader Impact & Notable Effects:
  • Responsible for >17 % of all STOP/Djvu infections in Southeast Asia during 2020 (Avast telemetry).
  • Frequently bundled with second-stage Cobalt Strike beacons, leading to full domain compromise within 72 h post-ransomware. Consequently:
    – Treat .adobe not as a standalone ransomware event but as a triple-extortion campaign (data exfiltration + encryption + auction).
    – Recommend invoking full IR playbook (MFA re-enrollment, certificate renewal, password vault rotation) rather than simple decryptor exercise.