Post-Incident Malware Scrub
Recovery Objective: To scan and sanitize all user data, logs, and configuration files before they are re-imported into the newly restored production environment.
Malware often uses “Living off the Land” techniques, hiding inside legitimate-looking files like PDF manuals or Excel macros. Re-importing these files without scrubbing can lead to an Immediate Re-infection loop.
The Sandbox Scan Method
Never scan your backup data on the “Live” OT network. Use an isolated, stand-alone “Scanning Station” (usually a dedicated laptop in the ETO office) that is not connected to the ship’s Bridge or Engine networks.
Deep Heuristic Scan
Use at least two different antivirus engines to scan the backup media. One should be a “Signature-based” scanner and the other a “Behavioral” scanner.
Macro Removal
Disable macros in all recovered Office documents. If a file *must* use a macro, it must be manually inspected by shore-side IT before use.
The Data Sanitization Workflow
Follow this flow for every piece of data returning to the OT network:
Identify High-Risk Files: Prioritize .exe, .bat, .ps1, and .docm files. These are the most likely to carry malware payloads.
Offline Scan: Connect the backup drive to the Sandbox Station. Perform a full disk scan.
Incremental Import: Move files back to the production system in small batches. Monitor the system for 15 minutes after each batch for spikes in CPU or network traffic.
Evidence for the “Lessons Learned” Report
Under IACS UR E26 §4.4.1.3, the incident response procedures must include reporting needed evidence of the incident. Furthermore, per §4.5.1.2, the ETO must ensure that recovery actions do not inadvertently result in the destruction of evidence that could provide valuable information on the causes of an incident. This preserved data is vital for the Pillar C: Post-Incident Review.
- File Name: (e.g., “engine_logs_2025.xlsx”)
- Threat Detected: (e.g., Trojan.Downloader.W97M)
- Action: (e.g., Deleted and restored from a month-old archive instead).
Professional Tip
If you are restoring a database (like the PMS or AMS history), coordinate with the equipment manufacturer (OEM). They can often provide a “Clean Script” that verifies the data structure hasn’t been modified to cause a system crash upon re-entry.
Next Security Phase
Post-Incident Debriefing
Post-Incident Debriefing Recovery Objective: To analyze the "Root Cause" of the incident and document the timeline to prevent recurrence and improve the ship's overall Cyber Resilience. The incident isn't truly over until the Post-Incident Review (PI...