Security Monitoring
& Logging
You can't defend what you can't see. Centralized security monitoring and logging enable real-time threat detection, rapid incident response, and compliance with regulatory requirements. Detect breaches in minutes, not months.
Why Security Monitoring Is Critical
You cannot defend what you cannot see. Without centralized logging and monitoring, attackers operate undetected for months while escalating privileges and exfiltrating data.
Average time to detect a breach without proper monitoring
Reduce detection time from months to minutes with proper SIEM implementation
Mandatory for PCI-DSS, HIPAA, SOC 2, and ISO 27001 compliance
Core Security Monitoring Components
Build a comprehensive security monitoring stack
Log Aggregation
Centralize logs from all systems, applications, and security tools
Examples:
- • ELK Stack
- • Splunk
- • Graylog
- • Datadog
Purpose: Single source of truth for all security events
SIEM Platform
Security Information and Event Management for correlation and analysis
Examples:
- • Azure Sentinel
- • Splunk ES
- • IBM QRadar
- • Elastic Security
Purpose: Detect patterns and anomalies across log sources
Alerting System
Real-time notifications for security events and threshold breaches
Examples:
- • PagerDuty
- • Opsgenie
- • VictorOps
- • Slack/Teams
Purpose: Immediate notification of critical security events
Threat Intelligence
Integrate threat feeds to identify known malicious actors
Examples:
- • MISP
- • AlienVault OTX
- • Recorded Future
- • ThreatConnect
Purpose: Enrich alerts with context and IOCs
Critical Log Sources
What to monitor for comprehensive security visibility
Identity & Access
- Authentication attempts (success/failure)
- MFA enrollment and usage
- Privilege escalation events
- Account lockouts
- Password changes/resets
Network & Firewall
- Firewall deny logs
- VPN connections
- Intrusion detection/prevention alerts
- DNS queries to suspicious domains
- Network traffic anomalies
Application & API
- Application errors and exceptions
- API authentication failures
- SQL injection attempts
- File upload/download events
- Rate limiting violations
Infrastructure & OS
- System login events
- Sudo/admin command execution
- Service start/stop events
- File integrity changes
- Kernel security events (SELinux/AppArmor)
Cloud & Containers
- Cloud API calls (CloudTrail/Activity Log)
- IAM policy changes
- Container deployments
- Kubernetes API server events
- Service mesh traffic logs
Security Tools
- Antivirus/EDR detections
- Vulnerability scan results
- Email security gateway blocks
- DLP policy violations
- WAF blocks and rate limits
Implementation Roadmap
Build your security monitoring capability step-by-step
Inventory Log Sources
2-3 daysIdentify all systems and applications that generate security-relevant logs
Tasks:
- Map all infrastructure components (servers, network devices, cloud services)
- Document authentication systems (IdP, VPN, SSH, databases)
- List all applications and their logging capabilities
- Identify security tools (firewalls, EDR, WAF, IDS/IPS)
- Note log formats, volumes, and retention requirements
Select SIEM/Log Platform
1 weekChoose a centralized logging and SIEM solution
Tasks:
- Estimate daily log volume (GB/day)
- Evaluate platforms: ELK Stack (open-source), Splunk, Azure Sentinel, Datadog
- Consider: scalability, cost, integration support, query capabilities
- Test with sample logs in a proof-of-concept environment
- Plan for log retention (90 days hot, 1+ year cold storage for compliance)
Deploy Log Collectors
1-2 weeksConfigure agents and forwarders to send logs to central platform
Tasks:
- Deploy log collection agents (Filebeat, Fluentd, Splunk UF, etc.)
- Configure syslog forwarding for network devices
- Integrate cloud platform logs (AWS CloudTrail, Azure Activity Log, GCP Audit)
- Set up structured logging for applications (JSON format recommended)
- Test log ingestion and verify data arrival in SIEM
- Implement log buffering and retry logic for reliability
Define Detection Rules
2-3 weeksCreate correlation rules to detect suspicious activity
Tasks:
- Start with high-fidelity rules: repeated failed logins, privilege escalation, new admin accounts
- Implement MITRE ATT&CK framework detections for common tactics
- Create baseline rules: detect deviations from normal behavior (time, location, volume)
- Integrate threat intelligence feeds to flag known bad IPs and domains
- Test rules against historical data to reduce false positives
- Document each rule: purpose, threshold, expected false positive rate
Configure Alerting
1 weekSet up alert routing and escalation workflows
Tasks:
- Define severity levels: Critical (page on-call), High (email + Slack), Medium/Low (dashboard)
- Integrate with incident management platform (PagerDuty, Opsgenie)
- Set up alert enrichment: include context (user, asset, recent activity)
- Configure alert deduplication and grouping to prevent fatigue
- Establish on-call rotation for security alerts
- Create runbooks for common alert types
Tune & Optimize
OngoingContinuously improve detection accuracy and reduce noise
Tasks:
- Review alerts daily for first 2 weeks, weekly thereafter
- Track false positive rate per rule and tune thresholds
- Suppress known benign activity (scheduled tasks, service accounts)
- Add new detection rules based on emerging threats and incidents
- Conduct monthly threat hunting exercises using SIEM queries
- Quarterly review: validate all log sources are sending data
- Simulate attacks (purple team) to test detection effectiveness
Security Monitoring Best Practices
✅ Enable time synchronization (NTP)
Why: Accurate timestamps are critical for incident investigation and correlation
✅ Use structured logging (JSON)
Why: Makes parsing, searching, and analysis significantly easier
✅ Protect log integrity
Why: Forward logs immediately to prevent attacker tampering. Consider write-once storage.
✅ Monitor the monitors
Why: Alert if log volume drops significantly—indicates potential blind spot or attack
✅ Implement log rotation and retention
Why: Balance storage costs with compliance requirements (typically 90 days minimum)
✅ Encrypt logs in transit and at rest
Why: Logs contain sensitive data: IPs, usernames, system details
Common Pitfalls to Avoid
❌ Alert fatigue from too many false positives
✅ Solution: Start with high-confidence rules. Tune aggressively. Better to miss 10% of events than ignore 100% due to noise.
❌ Logs stored only on the source system
✅ Solution: Forward logs immediately. Attackers delete local logs. Centralized logging prevents evidence destruction.
❌ No one is actually watching the alerts
✅ Solution: Assign clear ownership. Define SLAs for alert response (e.g., critical alerts acknowledged within 15 minutes).
❌ Monitoring only infrastructure, not applications
✅ Solution: Application-layer attacks (SQLi, XSS, business logic abuse) won't appear in infrastructure logs.
❌ Insufficient log retention for investigations
✅ Solution: Breaches are often discovered months later. Retain logs for at least 90 days, ideally 1 year.
Popular SIEM & Logging Platforms
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Measure Your Monitoring Effectiveness
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