PCI DSS 11.5.2: Change-Detection Mechanism for Critical Files
PCI DSS 11.5.2 requires organizations to implement file integrity monitoring (FIM) that automatically detects and alerts on unauthorized changes to critical system files. For SMBs managing cardholder data, this control is essential to prevent tampering, malware injection, and compliance violations. Without real-time change detection, you risk undetected breaches that auditors will flag immediately.
What this means
This control mandates deploying a change-detection mechanism—typically file integrity monitoring software—that continuously monitors critical files for unauthorized modifications. When changes occur, the system must immediately alert designated personnel so they can investigate and respond. Critical files include system binaries, configuration files, security tools, and any files containing sensitive data or authentication credentials. The mechanism must establish baselines of legitimate files and flag any deviations from those baselines.
How to comply
- 1.Identify all critical files requiring monitoring: system binaries, configuration files, authentication systems, security software, and cardholder data repositories.
- 2.Select and deploy file integrity monitoring (FIM) software that captures file attributes (checksums, permissions, timestamps, content hashes).
- 3.Establish baseline configurations for each critical file so the FIM tool can detect deviations.
- 4.Configure automated alerts to notify security personnel immediately when unauthorized changes are detected.
- 5.Document your change-detection strategy, including which files are monitored and who receives alerts.
- 6.Test the FIM solution quarterly to ensure alerts trigger correctly and personnel respond appropriately.
- 7.Retain file integrity logs for at least one year to demonstrate continuous monitoring during audits.
Evidence auditors look for
- File integrity monitoring tool logs showing daily scans of critical system files with no unauthorized changes detected.
- Alert configuration screenshots showing real-time notifications to security team email or SIEM.
- Baseline file snapshots documenting checksums and permissions for monitored critical files.
- Incident response logs showing timely investigation and remediation when unauthorized changes were detected.
- Quarterly FIM testing reports confirming alerts function correctly.
- Policy documentation defining which files are monitored and the change-detection process.
- SIEM or log aggregation reports consolidating FIM alerts across all monitored systems.
Frequently asked questions
When will FAQs be available?
The FAQ for this control is currently being prepared.
GRCWatch automates FIM configuration and alert aggregation, automatically logging file integrity monitoring events into your compliance dashboard so you have real-time visibility into critical file changes and easy audit evidence—no manual log collection required.
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