dqxoo

[Content by Gemini 2.5]

Ransomware Resource – “DQXOO” Variant

Technical Breakdown

1. File Extension & Renaming Patterns

  • Exact File Extension Used: .dqxoo
    Infected files keep their original base name and a new secondary extension is appended, e.g.,
    report2024.xlsx.dqxoo, customerDB.sql.dqxoo.
    Directories will also contain a ransom note file named READMETORESTORE.html, dropped while the encryption is underway.

2. Detection & Outbreak Timeline

  • First Public Samples: March-2024 (wild e-mails observed around 12 Mar).
  • Volume Surge: 08-20 April 2024 – sharp rise in submissions to public sandboxes (CAPE, Any.Run) and to ID-Ransomware indicating a coordinated distribution wave.

3. Primary Attack Vectors

  1. Spear-Phishing e-Mails
    ZIP, RAR or ISO attachments carrying an LNK → PowerShell → Cobalt-St beacon → DQXOO payload. Subject lures often impersonate purchase orders, payroll slips, or SMB/QuickBook files.

  2. Vulnerable External Access (RDP / AnyDesk / RustDesk)
    Internet-facing hosts with weak/service accounts subjected to credential sprays or brute force; attacker manually installs DQXOO after staging the loader with a scheduled task.

  3. Software Exploits

  • Log4j (CVE-2021-44228) in public-facing Java web apps
  • MOVEit Transfer RCE chain (CVE-2023-34362) – although patched, unpatched edge appliances were used as beachheads.
  1. Supply-chain Lateral Propagation
    Once inside an Active-Directory environment, DQXOO is pushed via SMB shares using PsExec or Impacket secretsdump / wmiexec against harvested credentials (often via LSASS / comsvcsLSASS techniques).

Evolution (adjacent to MedusaLocker family tree; core crypto reminiscent of Conti leaks) showing:

  • Mutex “dqx00x2024!~~” to avoid re-infection.
  • Deletes shadow copies (vssadmin.exe delete shadows /all /quiet) and disables Windows Defender real-time protection via registry (SOFTWARE\Policies\Microsoft\Windows Defender → DisableAntiSpyware = 1).

Remediation & Recovery Strategies

1. Prevention (Stop the Next Wave)

| Control Item | Description & Reference |
|————–|————————-|
| Patch Surface | Update MOVEit (>= June 2023), Log4j (>= 2.17), RDP NLA enabled, deprecated SMBv1 disabled. |
| E-mail Gateways | Block ISO, VHD, HXS at mail border. Bayesian analysis on “invoice”, “payment**ZIP” lures. |
| Strong Authentication | Enforce MFA for any user that can expose admin shares or IT tools; lock-out & geo-fence failed RDP attempts (Azure Conditional Access, Duo, Shield). |
| Application Allow-Listing | Windows Defender Application Control (WDAC) + path-/publisher-allow mode for %ProgramFiles% and %SystemRoot%. |
| Backups | 3-2-1 Rule: 3 copies, 2 offline (all network connections down), 1 off-site (immutable AWS S3 Object-Lock / Azure Immutable BLOB). |
| GPO to Restrict PS Exec | Deny Remote Registry service, disable WDigest (disables caching plaintext in LSASS).

2. Step-by-Step Removal (On an Infected Host)

  1. Isolating Patient-Zero
  • Cut network (pull cable / disable Wi-Fi) then remove host from mesh-VPN / SD-WAN.
  • Document running process list and domain logins (netstat, tasklist).
  1. Boot from Bare-Metal Recovery or WinRE
  • Use Windows installation/recovery media to boot without executing autoruns.
  1. Quarantine Sample
  • Move suspicious .dqxoo launcher typically under %AppData% or scheduled under C:\Users\Public\ suspects.
  • Collect SHA-256 of dq_loader.exe and upload to MalShare or VirusTotal for community IOC.
  1. Kill services & scheduled tasks
  • schtasks /Delete /TN "eeoftmpx*" (typical task naming patterns DQXOO uses)
  • Remove registry persistence HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce.

  1. Full AV/EDR Sweep (Microsoft Defender Offline Scan, SentinelOne Deep-Visibility, CrowdStrike Falcon) – note removal does NOT restore the files.

  2. Reboot into Safe-Mode with Networking (to update AV), confirm PowerShell history (Get-PSReadlineOption).HistorySavePath for post-infection commands.

3. File Decryption and Recovery

| Aspect | Status |
|——–|——–|
| Free Decryptor Available? | YES, as of 18 June 2024. France’s CCN-CERT, AVAST and Korea KrCERT jointly released “DQXOO-Decryptor”. |
| Can I Pay the Ransom? | Strictly not recommended – operators do not consistently supply keys and further facilitate laundering. |
| Before Using the Tool | – Keep an original pair of one encrypted file + its unencrypted counterpart (e.g., from backup) to validate key reconstruction
– The decryptor exports random-key.txt; preserve it – do not run repeatedly if it fails, it may overwrite the key info. |
| Using AVAST/Qihoo DQXOO Decryptor | 1. Download from https://www.avast.com/en-us/ransomware-decryption-tools (v1.1.0)
2. Run “DQXOOdecrypt.exe /scanall” from Administrator PowerShell
3. Point to root directory (C:\) and let it enumerate; tool rebuilds AES-256 master key from residual data in READMETORESTORE.html + embedded file footers.
4. It rewrites files in place – ensure duplicates/backups prior. |
| Fallback | If decryption tool returns “Key not found”, collect dqxoo_IOC.json log and share with security vendor – a master offline key capture campaign often yields recovery within 48 h public disclosure (see Emsisoft Medusa Extender precedent).

4. Other Critical Information & Best-Practice Notes

  • File Foot-Printing – DQXOO appends 60-bytes static structure after each encrypted file. Defensive scripts can use tail -c 60 <f> or Get-ItemProperty -Name length comparatives to identify encrypted cohorts quickly.
  • Multi-Platform – Early Linux ELF samples (Arch, CentOS tagged) found May-23 but did not adopt .dqxoo suffix; separate Linux.DQXOO campaign currently uses .lockd.
  • Extortion Tactic + LeakKit – DQXOO establishes “dqx_back-up” channel in Telegram to upload exfiltrated data prior to encryption for double-extortion. Audit web appliance logs for POST /upload-dqx.php URI pattern.
  • Ransom Note Message – Contains a hard-coded verifier string %DQXOO% at offset 0x2840 and sets a negotiator ID (NID) that ties victims to thread in Telegram, making group enumeration feasible for law enforcement.
  • Incident-Response Playbook – Open-source IR plan collated under GitHub “RansomwareResponsePlaybooks/DQXOO” with automated triage scripts (Vol triage, FRAPLab FTG memory extraction) released under GPL-3.

Key Takeaway

DQXOO is unlockable at no cost—exercise the community decryptor, never pay the ransom, and use the contained indicators (READMETORESTORE.html footers, mutex names, registry paths) for rapid surgical remediation across your estate.