Emergency Fix: Remove Zotob.D with These Proven Methods

Emergency Fix: Remove Zotob.D with These Proven Methods

Overview

Zotob.D is a Zotob worm variant (targets unpatched Windows 2000 and some other Windows systems) that copies an executable (commonly windrg32.exe), opens network ports (e.g., 1117, 6667, 445), modifies the hosts file to block AV sites, creates autorun registry entries, stops services, deletes/changes registry keys and files, and may open backdoors (FTP/IRC/TFTP). Symptoms: presence of windrg32.exe or botzor.exe, modified hosts file, registry Run/RunServices entries named like WINDOWS SYSTEM, excessive traffic on TCP 445, system instability or repeated reboots.

Immediate emergency steps (do these first)

1. Isolate the machine
   • Disconnect from network and internet immediately (unplug Ethernet, disable Wi‑Fi).
2. Do not restart (if system is unstable, avoid rebooting unless required for safe scans).
3. Boot to a clean environment
   • Prefer a clean, patched Windows PE/Rescue USB or a trusted antivirus rescue ISO so the worm’s files aren’t running.
4. Run up-to-date offline scans
   • Use a reputable rescue scanner (Kaspersky Rescue Disk, Bitdefender Rescue, Microsoft Safety Scanner) to perform full-system scans and remove detected Zotob variants.

Manual cleanup (if automated tools fail)

1. Boot from rescue media or Safe Mode with Networking (rescue media preferred).
2. Delete known payloads: search for and remove files like windrg32.exe, botzor.exe, wintbp.exe in %SYSTEMROOT% and %SYSTEMROOT%\system32.
3. Remove autorun registry entries:
   • HKLM\Software\Microsoft\Windows\CurrentVersion\Run — delete values named WINDOWS SYSTEM (data: botzor.exe / windrg32.exe).
   • HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices — delete same if present.
4. Restore services/startup values:
   • Check HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess Start and reset to default (usually 2 for Automatic); restore any changed service Start types that the worm altered.
5. Clean hosts file:
   • Edit %windir%\system32\drivers\etc\hosts and remove malicious lines (look for strings like “Botzor2005 Made By…” or entries blocking AV sites).
6. Remove leftover scheduled tasks, temp files, and suspicious DLLs/executables in common locations (Temp, Program Files, Windows\System32).
7. Check open ports/processes:
   • Use netstat and tasklist (from rescue environment) to find/listen ports 1117/6667/445 and kill related processes.
8. Search for mutexes and persistence mechanisms used by IRC/FTP backdoors and remove them where possible.

Post‑remediation steps

1. Apply security updates: install MS05-039 patch (or ensure system is fully patched) — note Zotob exploits a Plug-and-Play vulnerability fixed by MS05-039.
2. Install or update reputable antivirus/endpoint protection and run a full scan.
3. Change all local and domain passwords (treat credentials used on the infected host as compromised).
4. Monitor network traffic and logs for unusual connections (IRC, FTP, unexpected outbound connections).
5. Rebuild the system if integrity is uncertain: if the system was heavily modified or you cannot be sure all backdoors are removed, perform a full OS reinstall from known-good media and restore data from clean backups.
6. Notify stakeholders and, if applicable, law enforcement (corporate incidents may require incident response).

Tools & resources

• Microsoft Windows Malicious Software Removal Tool (MSRT) — includes Zotob signatures (older releases covered Zotob.D).
• Microsoft Security Advisory MS05-039 and malware encyclopedia entries (Zotob variants).
• Rescue ISOs: Kaspersky Rescue Disk, Bitdefender Rescue, ESET SysRescue.
• One‑off scanners: Microsoft Safety Scanner, Malwarebytes (offline scan recommended).

Quick checklist (for technicians)

• Isolate machine from network
• Boot rescue media / perform offline scan
• Remove windrg32.exe / botzor.exe and related files
• Delete Run / RunServices registry entries (WINDOWS SYSTEM)
• Clean hosts file
• Restore modified services and registry keys
• Patch OS and update AV signatures
• Change passwords and monitor network
• Reinstall OS if compromise cannot be fully verified

If you want, I can produce step‑by‑step Windows command lines (regedit .reg snippets, netstat/tasklist commands, or exact file paths and reg keys) for each manual step.