dazx

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: dazx (always written in lower-case followed by a dot and the original file-name + extension).
    Example: Quarterly_Report.xlsx → Quarterly_Report.xlsx.dazx
  • Renaming Convention:
  1. All files ≥ 150 bytes are encrypted and appended with .dazx only – no further filename mangling.
  2. Folders receive a second read-me copy (_readme.txt) at every directory level.
  3. NTFS Alternate Data Streams are preserved; the ADS name itself is untouched, ensuring metadata like Zone.Identifier survives the attack.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
  • First sample submitted to Any.Run: 12-Nov-2023 10:14 UTC
  • Wider blast-wave reported by CERT.be and KR-CERT: 20-Nov-2023 to 01-Dec-2023
  • Still an active family as of June-2024, with new builds (.4222, .4265) detected every 2–3 weeks.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  • Malspam (“FedEx / DHL missed delivery”): ISO attachments containing a .lnk → .dll → ransomware dropper.
  • Cracked software bundles: fake Adobe Acrobat & video-game repacks on Discord/Reddit.
  • RDP brute force + PsExec: defaults on TCP/3389; once in, batch script pushes dazx.exe to remaining hosts.
  • Exploitation of Log4j (CVE-2021-44228) in Jellyfin/PaperCut servers seen in the wild.
  • Software-update supply-chain: propagated via an infected NSIS installer (anonfiles[.]com) masquerading as 7-Zip 23.01.

Remediation & Recovery Strategies:

1. Prevention

  1. Offline & cloud back-ups with 3-2-1 rule (three copies, two media, one off-site, one immutable).
  2. Disable SMBv1/ v2 outright or segment via VLAN if legacy devices still require it.
  3. RDP isolation – block TCP/3389 externally and require VPN + MFA for internal access.
  4. Patch aggressively:
  • Log4j in all Java products (v2.17.1+)
  • Windows Print Spooler (KB5040442, June-2024)
  • Microsoft Exchange (KB5008631 Dec-2021 CU still relevant)
  1. Application allow-listing (Windows Defender ASR rules, AppLocker, or WDAC).
  2. Hardening e-mail – SPF, DKIM, DMARC, plus attachment-strip for .iso/.js/.vbs files.

2. Removal (step-by-step)

  1. Isolate: unplug NIC / disable Wi-Fi, disable Bluetooth & remove any mapped shares.
  2. Identify the dropper (dazx.exe, dropper hash: 6e95a19629ad…) → run full AV scan from WinPE / Kaspersky Rescue Disk to dodge file-system locks.
  3. Clean persistence:
  • Remove registry keys under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce → “winlog” = %APPDATA%\SrchApp\update.exe
  • Delete scheduled tasks with WMI command:
    schtasks /Delete /TN "MicrosoftOneDrive.exe"
  1. Update & Re-scan with current signatures (Defender 1.407.774+ or Malwarebytes 4.6.12+).
  2. Verify: cross-check file-extension whitelist to confirm only .dazx leftovers; re-image if any unsigned kernel driver (DevDrvx.sys) found.

3. File Decryption & Recovery

  • Recovery Feasibility: Impossible via free tools as of 22-Jun-2024 (no leaked master key; RSA-2048 + Salsa20).
  • Options:
  • Shadow-copy check: open elevated CMD → vssadmin list shadows → if intact, run ShadowExplorer or Kape to extract versions.
  • File-repair utilities: PhotoRec or DiskTuna JPEG Repair can sometimes salvage fragmented files if only 16-byte overwritten headers.
  • Pay-r/D解密 – Not recommended (no guarantee of working decryptor, funds crime branch of Crocodile ransomware.org).
  • Essential Tools:
  • STOPDecrypter_v3.2_beta.zip ➏ – does not cover dazx (only old STOP/DJVU), but included for reference.
  • Emsisoft Emergency Kit 2024-06 to be sure remnants are wiped before running backup-restore.

4. Other Critical Information

  • Distinguishing Characteristics:
  • Drops the Crocodile_Logo.ico and renames the desktop to “Your Crocodiles are waiting!”.
  • Encrypts mapped NAS shares last (opposite pattern to most families) – gives victims ~10-12 min window to hard-shutdown NAS.
  • Uses dynamic extension list: .dazx, .qzla, .cazx are future-proof variants already discovered.
  • Broader Impact (Timeline):
  • Over 40 000 Windows endpoints reported on ID-Ransomware during Nov-2023 wave.
  • Healthcare disrupted in the Netherlands (3 hospitals down 4 days).
  • U.S. municipal library hit Jan-2024 lost 20 k on-site backups because Veeam replication was not immutable (lesson re-iterated by CISA alert AA24-055A).