audit-logging

Audit Logging

Implement comprehensive audit logging for compliance, security monitoring, and forensic analysis across infrastructure and applications.

When to Use

• Setting up centralized logging for compliance frameworks (SOC 2, HIPAA, PCI DSS)
• Implementing security event monitoring and alerting
• Building audit trails for regulatory requirements
• Configuring log retention and tamper-proof storage
• Integrating application logs with SIEM platforms

Log Categories

audit_events:
  authentication:
    - Login attempts (success and failure)
    - MFA enrollment and verification events
    - Session creation, renewal, and termination
    - Password changes and resets
    - API key and token generation

  authorization:
    - Access grants and denials
    - Permission changes and role assignments
    - Privilege escalation events
    - Resource sharing modifications
    - Policy evaluation results

  data_access:
    - Read operations on sensitive data
    - Write and update operations
    - Delete and purge operations
    - Bulk export and download events
    - Data classification changes

  administrative:
    - Configuration changes
    - User and group management
    - System startup and shutdown
    - Backup and restore operations
    - Network and firewall rule changes

  system:
    - Service health state changes
    - Resource provisioning and deprovisioning
    - Certificate and key rotation events
    - Scheduled job execution results
    - Integration and webhook events

Rsyslog Configuration for Centralized Logging

# /etc/rsyslog.d/50-audit.conf

# Load imfile module to read application logs
module(load="imfile")

# Forward auth logs
input(type="imfile"
  File="/var/log/auth.log"
  Tag="auth"
  Severity="info"
  Facility="auth"
)

# Forward application audit logs
input(type="imfile"
  File="/var/log/app/audit.log"
  Tag="app-audit"
  Severity="info"
  Facility="local0"
)

# Structured JSON template
template(name="json-audit" type="list") {
  constant(value="{")
  constant(value="\"@timestamp\":\"")    property(name="timereported" dateFormat="rfc3339")
  constant(value="\",\"host\":\"")       property(name="hostname")
  constant(value="\",\"severity\":\"")   property(name="syslogseverity-text")
  constant(value="\",\"facility\":\"")   property(name="syslogfacility-text")
  constant(value="\",\"tag\":\"")        property(name="syslogtag" format="json")
  constant(value="\",\"message\":\"")    property(name="msg" format="json")
  constant(value="\"}\n")
}

# Forward to central syslog server over TLS
action(
  type="omfwd"
  target="syslog.internal.example.com"
  port="6514"
  protocol="tcp"
  StreamDriver="gtls"
  StreamDriverMode="1"
  StreamDriverAuthMode="x509/name"
  template="json-audit"
  queue.type="LinkedList"
  queue.size="50000"
  queue.filename="fwd_audit"
  queue.saveonshutdown="on"
  action.resumeRetryCount="-1"
)