Logging and monitoring

To meet the PCI DSS 4.0 logging and monitoring requirement, you must monitor security events across your cardholder data environment (CDE) and retain logs so you can investigate suspicious activity and reconstruct events. Operationally, that means defining what to log, centralizing collection, setting alerting and review routines, and proving it works with durable evidence. ¹

Key takeaways:

• Scope logging to the CDE and connected systems, then document the event coverage you expect to see.
• Centralize logs, protect them from tampering, and run consistent review and alert triage routines.
• Audit success depends on evidence: configurations, samples, review records, and investigation-ready retention. ¹

The logging and monitoring requirement is an execution requirement, not a policy requirement. Auditors and assessors look for two things: (1) you can detect meaningful security events in and around the CDE, and (2) you can produce trustworthy logs that support an investigation. If either is weak, incident response becomes guesswork and PCI evidence becomes “we think we have logs,” which fails quickly under scrutiny.

Treat this requirement as a small operating system: define event expectations, collect and normalize logs centrally, alert on high-signal conditions, and run a review cadence that produces records. The fastest path is to start with a CDE-centric log inventory (what systems exist, what they emit, and where it goes), then close gaps with standard configurations and a simple but consistent review procedure.

If you manage third parties that touch payment flows (for example, managed SOC, hosting, payment processors, MSPs), include them in the logging design. You still need to show you monitor security events relevant to your environment and can access logs needed for investigations. ¹

Regulatory text

Requirement (PCI-05): “Monitor security events and retain logs for investigations.” ¹

Operator meaning: you need a functioning capability to (a) observe security-relevant activity affecting the CDE and (b) keep logs long enough, and reliably enough, to support incident investigation and scoping. A written policy alone will not satisfy this. Your assessor will expect to see systems generating logs, logs collected and protected, review/alerting in operation, and retained records that can be produced on request. ¹

Plain-English interpretation of the logging and monitoring requirement

You pass this requirement when you can answer these questions with evidence:

• What happened? You capture events that describe authentication, authorization, administrative actions, security control changes, and suspicious traffic patterns relevant to the CDE.
• Where did it happen? You can tie events back to systems in scope (CDE and connected components).
• Who did it? Events include reliable identifiers (user, service account, source host, API key where applicable).
• When did it happen? Timestamps are consistent enough to reconstruct sequences across systems.
• Can you prove it? Logs are protected against loss and tampering, and retained so investigations can look back in time. ¹

Who it applies to

Entities: merchants and service providers in scope for PCI DSS. ¹

Operational context (where this shows up):

• Any environment that stores, processes, or transmits cardholder data, plus systems that can impact CDE security (jump hosts, identity providers, admin workstations, configuration management, endpoint security consoles).
• Hybrid environments: on-prem plus cloud logging sources (cloud control plane, WAF, load balancers, container platforms) if they support or touch the CDE.
• Third parties operating parts of the CDE (managed hosting, managed detection and response, managed firewall), where you must still demonstrate monitoring coverage and investigation access paths. ¹

What you actually need to do (step-by-step)

Step 1: Define log scope and event coverage

1. Map the CDE and “connected-to-CDE” systems that could affect confidentiality or integrity of payment data (network, identity, endpoints, critical apps, security tooling).
2. Create a logging coverage matrix: system type → required event categories → log source → destination (SIEM/log platform) → owner.
3. Set minimum event categories for each system. Keep it practical:
   • Identity/auth: logins, MFA events, failures, privilege changes
   • Admin actions: configuration changes, firewall rule changes, policy changes
   • System/security: EDR alerts, anti-malware events, integrity alerts where available
   • Network/app: WAF alerts, IDS/IPS alerts, VPN events, critical application security events (authentication/authorization failures, suspicious access patterns)

Deliverable: “CDE Logging Coverage Matrix” with owners and sources.

Step 2: Centralize logging and standardize collection

1. Choose a central log repository (SIEM or centralized log management).
2. Onboard sources in priority order: identity + perimeter + admin change logs first, then endpoints and application logs.
3. Normalize timestamps and fields so investigations can correlate events. Define a standard for time sync and log format mapping in your SIEM.
4. Verify ingestion with a simple acceptance test per source: generate a known event, confirm it appears centrally, confirm searchable fields (host, user, action).

Recommended control approach: centralize logging and perform daily/periodic review procedures. ¹

Step 3: Protect logs (integrity, access control, and survivability)

1. Restrict access to log systems to approved roles (security operations, limited administrators). Document who can change log configurations, who can read logs, and who can delete.
2. Enable immutability/anti-tamper features available in your platform (write-once storage options, retention locks, or equivalent controls).
3. Separate duties where possible: people who administer systems should not be able to erase their own trails without detection.
4. Back up or replicate logs so a single outage or compromise does not wipe evidence.

Evidence focus: show configuration screens/settings, role assignments, and change control records.

Step 4: Implement monitoring: alerts plus a review routine

1. Define alert use cases tied to CDE risks (admin logins from unusual locations, repeated authentication failures, privilege escalation, WAF blocks on payment endpoints, changes to logging configurations).
2. Set triage ownership and workflow: who receives alerts, where they are tracked (ticketing system), and required response steps.
3. Run scheduled reviews for items that aren’t fully alert-driven (for example, daily security event review and periodic trend review). Your cadence should match your environment’s risk and volume, but it must be consistent and provable.
4. Document escalation into incident response when thresholds are met and ensure the path is used in practice.

Recommended control approach: centralize logging and perform daily/periodic review procedures. ¹

Step 5: Set retention and prove investigation readiness

1. Define retention requirements internally for investigation usefulness (short retention fails investigations; overly long retention can increase storage and privacy obligations). Align retention with your incident response needs and PCI expectations.
2. Test an investigation drill: select a timeframe and reconstruct a simple scenario (user login → privileged action → firewall change). Confirm you can retrieve logs and correlate across sources.
3. Maintain chain-of-custody practices for exporting logs when an investigation occurs.

Deliverable: “Logging Investigation Drill Record” showing queries run, systems checked, and outcomes.

Required evidence and artifacts to retain

Keep artifacts that prove design and operation:

Design & scope

• CDE diagram and system inventory (in-scope and connected)
• Logging coverage matrix (sources, event types, owners)
• Logging and monitoring procedure (review cadence, triage, escalation)

Configuration & access

• SIEM/log platform configuration exports or screenshots (data sources onboarded, parsing rules where relevant)
• Role-based access control lists for log platforms
• Evidence of integrity controls (immutability/retention lock settings where applicable)

Operational records

• Log review records (checklists, analyst notes, dashboards snapshots tied to dates)
• Alert tickets with timestamps, triage notes, and resolution
• Change management records for logging configuration changes
• Investigation drill outputs and a sample of real investigations (redacted)

Third-party evidence (if applicable)

• Contract/SOW language or control attestations showing the third party provides log access, retention, and monitoring relevant to your CDE
• Access method documentation (portals, APIs, or scheduled exports)

Common exam/audit questions and hangups

Assessors tend to press on these areas:

• Scope clarity: “Show me all systems in the CDE and where their logs go.”
• Completeness: “Do you log admin actions and security control changes, or only system errors?”
• Evidence of review: “Who reviews logs, how often, and where is the proof it happened?”
• Integrity: “Can a system admin delete logs or disable forwarding without detection?”
• Retention realism: “Can you retrieve logs from the period needed to investigate a suspected compromise?” ¹

Frequent implementation mistakes and how to avoid them

Mistake	Why it fails	Avoidance pattern
Logging exists, but not centralized	Investigations become slow and incomplete	Centralize logs; track onboarding in a coverage matrix 1
No proof of ongoing review	Auditors can’t verify operation	Keep dated review records and alert tickets
Over-collecting low-value logs	Noise hides real events and increases cost	Start with high-signal CDE events; expand deliberately
Weak access controls on logs	Attackers can erase evidence	Separate roles, lock retention, monitor config changes
Third-party blind spots	You can’t investigate a hosted component	Contract for log access and monitoring artifacts; test retrieval

Enforcement context and risk implications

No specific public enforcement cases were provided in the source catalog for this requirement. Practically, logging gaps raise breach impact because you cannot determine scope, dwell time, or affected systems with confidence. That uncertainty tends to widen containment actions, customer notifications, and forensic costs, and it complicates PCI validation after an incident. ¹

Practical 30/60/90-day execution plan

Days 0–30: Get to “known coverage”

• Inventory CDE and connected systems; confirm log sources.
• Publish the logging coverage matrix with system owners.
• Stand up/confirm a central log platform and onboard highest-risk sources (identity, perimeter, admin change logs).
• Define the log review routine and create a simple review record template (ticket or checklist).

Days 31–60: Turn on monitoring you can operate

• Add priority application logs for payment flows and administrative interfaces.
• Implement alerting use cases for high-risk events; connect to ticketing.
• Lock down log access, document roles, and add monitoring for logging configuration changes.
• Run a tabletop or short investigation drill and capture outputs as evidence.

Days 61–90: Make it audit-proof

• Close remaining log source gaps from the matrix.
• Tune alerts to reduce noise; document tuning changes.
• Validate retention by retrieving logs from older periods and showing correlation across sources.
• Package evidence for assessment: scope, configurations, review records, tickets, and drill results.

Where Daydream fits: Daydream can serve as the system of record for the logging and monitoring requirement by tracking the coverage matrix, mapping owned controls to PCI DSS expectations, and collecting time-stamped evidence (review records, tickets, and configuration exports) so assessments don’t turn into a document scramble. ¹

Frequently Asked Questions

What systems must be included to satisfy the logging and monitoring requirement?

Start with all systems in the CDE, then include connected systems that could impact CDE security (identity, admin access paths, network/security controls). Your evidence should show you made a reasoned scoping decision and implemented it. ¹

Do we need a SIEM to meet PCI DSS 4.0 logging and monitoring?

PCI DSS 4.0 requires monitoring and investigation-ready retention, not a specific product. A SIEM is a common way to centralize logs and prove review, but centralized log management can also work if it supports secure retention, search, and operational records. ¹

What does an assessor accept as proof that logs are reviewed?

Dated artifacts: review checklists, dashboard snapshots tied to a day, analyst notes, and alert tickets with triage actions. Verbal statements without records usually fail.

How should we handle logging when a third party runs part of the payment environment?

Contract for log access, retention, and monitoring artifacts that relate to your CDE, then test retrieval during an investigation drill. Keep the evidence package from the third party alongside your internal logging records.

How do we prevent log tampering in practice?

Restrict who can administer the logging pipeline, enable retention locks or immutability features where available, and monitor changes to log forwarding and retention settings. Keep change records for any logging configuration updates.

What’s the fastest way to close gaps without boiling the ocean?

Build the coverage matrix, onboard identity and perimeter logs first, then expand to admin actions and critical application events. Tie every onboarding step to a test event and a retained screenshot or export.

Related compliance topics

• 2025 SEC Marketing Rule Examination Focus Areas
• Access and identity controls
• Access Control (AC)
• Access control and identity discipline
• Access control management

Footnotes

1. PCI DSS v4.0, PCI DSS Document Library