IncidentResponsev2

4.51 Perform Recovery Monitoring and Validation

Task Conduct Active Monitoring and Validation During and After Recovery to Ensure Threats Have Been Eradicated

Conditions

Once systems are being restored and users begin returning to normal operations, the operator will execute recovery monitoring and validation procedures to confirm there are no remaining threats or signs of compromise in the environment.

Operator Note: Recovery is the period where risks remain high → attacker tools missed during eradication or latent persistence mechanisms may attempt to resume. Active monitoring during this phase is critical.

Standards

Team member establishes active monitoring for restored systems.
Team member validates restored systems for security and performance baselines.
Team member monitors network, endpoints, and enterprise resources for abnormal activity.
Team member documents monitoring actions, observations, and any anomalies detected.
Team member escalates immediately if indicators of compromise (IOCs) or suspicious behavior are observed.

End State

Recovery period completes without detection of malicious activity, and validation demonstrates that systems and users have returned to normal, secure operations.

Notes

Monitoring and validation should continue through the initial weeks after recovery.
Recovery validation includes performance, functionality, AND security verification.
Any detected anomalies must be treated as potential indicators of ongoing compromise.

Manual Steps

Step 1: Establish Monitoring Coverage

Ensure all restored systems are:

Online and enrolled in EDR/XDR solution
Actively reporting telemetry (no gaps in coverage)
Under antivirus and log collection coverage

Operator Note: Any “silent” systems not reporting must be investigated immediately.

Step 2: Conduct Host-Level Validation

Windows/Linux/macOS

Verify no unexpected processes running
Verify no unauthorized startup entries or tasks
Validate user accounts and permissions

Tools

EDR/XDR → Crowdstrike, SentinelOne, Defender ATP
Sysinternals (Windows) → Process Explorer, Autoruns
systemctl / launchctl (Linux/macOS) → Active service enumeration

Step 3: Conduct Network-Level Monitoring

Validate all restored hosts communicate only on expected ports and protocols.
Detect unusual traffic patterns (C2, port scanning, brute forcing).
Monitor DNS requests for suspicious domains.

Tools

Zeek (Security Onion) → Network flow analysis
IDS/IPS → Snort, Suricata
Firewall/Proxy Logs → Unexpected destinations or high volumes

Step 4: Conduct User and Enterprise Monitoring

Confirm no abnormal user authentication or access attempts.
Monitor email, file shares, and privileged accounts.
Validate business processes resume securely.

Tools

SIEM → Splunk, Sentinel, ELK
Email Security Gateway → Proofpoint, M365 Defender
AD Logs → Authentication and authorization monitoring

Step 5: Validate System Performance and Stability

Verify systems run without performance degradation (possible malware or crypto mining remnants).
Validate system/app logs show no errors related to recovery process.
Confirm backups resume as normal and are not impacted.

Operator Note: Some malware reactivates after restart — post-recovery performance issues can be an IOC.

Step 6: Document Findings and Validate Completion

Record monitoring coverage, checks performed, and validation results.
If no malicious activity is detected after monitoring period (typically 1-2 weeks post recovery), document and mark recovery validation as complete.

Operator Note: Always retain recovery monitoring documentation as part of incident record for Lessons Learned.

Running Script (Windows - Verify EDR and AV Status)

Get-MpComputerStatus

Linux/macOS (Check Running Services)

ps aux
systemctl list-units --type=service

Network (Zeek - Check Connections)

cat conn.log | grep -v "normal_ports"

Dependencies

Full enrollment of recovered systems into security monitoring (EDR/AV/SIEM)
Coordination with system owners and IT ops
Predefined IOC watchlists from IR team
On-call IR and security staff for escalation

Other Available Tools

Tool	Platform	Installation	Usage
EDR/XDR Platforms (Crowdstrike, SentinelOne, Defender ATP)	Cross-platform	Enterprise deployment	Endpoint and host monitoring
SIEM (Splunk, Sentinel, ELK)	Cross-platform	Enterprise deployment	Correlate enterprise security events
Security Onion (Zeek, Suricata)	Network	Sensor deployment	Network traffic analysis
Sysinternals (Process Explorer, Autoruns)	Windows	Download	Validate host process integrity and startup persistence

Operator Note: Automated and manual validation combined gives the best coverage.

Operator Recommendations and Additional Tools

Operator Checklist

Confirm all restored systems are enrolled in security monitoring.
Validate hosts for clean running state and performance.
Monitor network activity for anomalies.
Monitor enterprise authentication and privileged accounts.
Document validation activities and monitoring coverage.
Escalate any suspicious detections immediately.
Finalize recovery validation after monitoring period concludes.

Best Practices

Start monitoring immediately → do not wait for users to return.
Monitor for at least 1-2 weeks post-recovery for latent threats.
Correlate across host, network, and user activity for anomaly detection.
Retain all records for compliance and post-incident review.

References

Security Onion - Network Security Monitoring
MITRE ATT&CK - Persistence
Sysinternals Suite

Revision History

Date	Version	Description	Author
2025-05-02	1.0	Fully generated operator guide for recovery monitoring and validation with technical procedures and checklist	Leo