Whether pulling items together for a holiday dinner or prepping weekly meals, you need to have all the ingredients necessary to cook the meals you want to eat. Often, this means making a grocery list, checking off items as you take them from the shelves, and, possibly, grumbling when one of the items isn’t available.
In the IT and business worlds, audit logging is the shopping list that helps organizations with compliance readiness. Audit logs provide documentation about the activities occurring across the IT environment. When organizations track this information, they have insight into current security control effectiveness and any issues that can undermine security, compliance, and operational integrity.
By understanding how audit logging enables protecting assets and documenting security activities, organizations can implement best practices to achieve their compliance objectives.
What Are Audit Logs?
Often called audit trails, audit logs are chronological, security-relevant records documenting the sequence of activities related to operations, procedures, or events. They are immutable logs that answer questions about:
- Who or what took action?
- What action did they take?
- When did they take the action?
- Where did they take the action?
By aggregating and correlating the audit logs, organizations can work toward answering why and how the person or technology took an action.
Unlike general-purpose logs that might track system performance or application errors, audit logs are specifically designed to provide a verifiable trail of actions for:
- Accountability: Tracking who did what and when, ensuring users and administrators can be held responsible for their actions.
- Forensic investigation: Providing detailed event records that help security teams reconstruct incidents and understand root causes.
- Compliance verification: Demonstrating adherence to regulatory requirements by proving that the organization followed key security and operational controls.
What Are the Different Types of Audit Logs?
Audit log is the overarching term for any data that an organization’s digital systems generate. They typically fall into one of the following categories:
- User activity logs: Recording login attempts, session durations, and actions taken within systems or applications.
- System event logs: Capturing significant activities that operating systems or infrastructures perform, like startup, shutdown, process crashes, service restarts, or system errors.
- Application logs: Tracking how software components are accessed and used, including create, read, update, and delete actions.
- Database audit logs: Documenting queries, table modifications, and permission changes
- Network audit logs: Monitoring connections, firewall changes, and data transfers.
- Administrative or privileged access logs: Detailing actions taken by users with elevated permissions.
- Security logs: Recording authentication events, failed access attempts, and alerts from security tools like SIEMs, IDS/IPS, or firewalls.
Configuration and change management logs: Capturing modifications that IT, security, or other internal teams make to systems, applications, or configurations. - File access logs: Detailing when files are opened, modified, or deleted to detect data exfiltration or insider threats.
What Should Be in an Audit Log?
To be effective for security forensics and compliance audits, typical audit log schema components include:
- Timestamp: Date and time event occurred, synchronized across all systems to establish a timeline for events.
- User/service identity: Specific user account, user ID, service account, or automated process that initiated the action to establish accountability.
- Source IP address: Network address from where the action originated to identify the geographic location or system involved.
- Event Type and Action: Description of the event, such as ‘user_login’, ‘file_delete’, or ‘permission_change’.
- Target resource: Object that the action performed on, such as a filename, database record ID, or user account name.
- Outcome: Action’s success or failure.
- Unique event ID: Distinct identifier for each log entry, which aids in tracking and correlation across different systems.
What Is the Difference Between Audit Logging and Event Logging?
Although sometimes used interchangeably, audit logging and event logging have a subtle but critical difference. While event logging provides insight about how systems operate, audit logging enables organizations to prove that their controls work and they have established documented accountability.
The two types of logging differ across the following:
- Purpose: While event logging captures everything from performance metrics to information events that happen in a system, audit logging creates verifiable records of use and system actions that affect security, data integrity, or compliance.
- Audience: Technical users, like IT operations and DevOps teams, use event logging, security teams, compliance teams, and auditors use audit logs.
- Scope: While event logs are broad and technical, audit logs are narrow and intentional, focusing on who took actions, especially when the activities are tied to sensitive data or configuration changes.
What Are Common Use Cases for Audit Logging?
The detailed, chronological audit logs often act as the foundation for various business and security functions because they provide the verifiable actions that the organization takes when implementing broader policies.
Security Incident Response
During a security incident or security breach, incident response teams use audit logs to gain visibility into scope and impact. The audit log data enables them to:
- Reconstruct the attacker’s timeline.
- Identify compromised accounts.
- Determine impacted or accessed systems.
- Pinpoint exfiltrated data.
For example, according to a Security Boulevard article, security researchers at Palo Alto Networks spotted a threat actors extorting organizations after compromising their cloud environments. When using the audit logs, security teams can build alerts that take advantage of finding from multiple analytical techniques.
Compliance and Regulatory Requirements
Most compliance mandates and frameworks include audit logging as a required control. The audit logs act as the documentation proving that the organization’s security, privacy, and data protection controls function as intended and comply with the external regulations’ requirements.
User Activity Monitoring
With most organizations using cloud services and infrastructures, audit logging’s ability to document and track user activity enables security and compliance objectives. Through appropriate log collection, aggregation, and analysis, organizations can establish baselines for normal user behavior. Then, they use the same logs to flag anomalous activities, like an employee accessing sensitive files outside of business hours or a service account performing actions inconsistent with its function.
Tracking Changes to Cloud Infrastructure
In dynamic cloud environments, audit logs help organizations keep track of changes. For example, cloud provider logs, like AWS CloudTrail, capture all API calls made to the environment. Security teams use this data to track all changes related to the organization’s security posture, like creation of a new security group or deletion of a storage bucket.
Best Practices for Audit Logging and Compliance Readiness
Fundamentally, audit logging acts as documented proof that an organization implemented and maintained the security controls that a compliance mandate or framework requires. Additionally, since audit logs provide real-time insight into systems, organizations can use these to ensure security controls act as intended or take action to remediate a potential compliance violation.
Some best practices that organizations can take include the following:
- Define and enforce a centralized log ingestion strategy: Ensure all relevant systems, applications, network devices, cloud services feed into a single log analysis platform or security information and event management (SIEM) analysis for holistic visibility and audit readiness.
- Enable detailed audit logging of user and system actions: Capture who did what, when, from where, and what changed, like configurations, access, roles, or queries.
- Implement role-based access control (RBAC) and authenticated access: Implement and maintain the principle of least privilege to sensitive log data by limiting access to logs and log management functions to authorized roles only.
- Ensure log immutability and tamper-resistance: Protect archived audit logs from deletion or modification.
- Align logging practices to regulatory frameworks: Map log sources, retention, controls, reports to the organization’s specific frameworks and regulatory requirements.
- Standardize log formats: Parse audit logs and define important log fields, then normalize them to a standard format.
- Correlate logs & monitor for anomalous activity: Use correlation, anomaly detection, and alerting to detect unusual changes that may indicate a compliance breach or insider threat.
- Automate Analysis and Alerting: Create high-fidelity security alerts and leverage artificial intelligence (AI) to identify remediation activities and understand attacker timelines.
- Develop dashboards and scheduled reports for audit-ready insights: Develop dashboards and automated reports that surface compliance-relevant metrics to proactively identify potential compliance gaps.
Graylog: Accelerate Compliance Readiness with Audit Log Management
Using Graylog, organizations can accelerate compliance readiness by using our cloud-native capabilities and out-of-the-box content to gain immediate value from their logs. Our anomaly detection ML improves over time without manual tuning, adapting rapidly to new data sets, organizational priorities, and custom use cases so that you can automate key user and entity access monitoring.
Our purposeful approach to AI-powered security operations speeds up investigations, reduces errors, and gives teams confidence in their decision-making capabilities. With Graylog’s context-rich investigations, threat-smart prioritization, and frictionless workflows, security teams cut through noise and reduce alert fatigue, all while documenting their security controls’ effectiveness and response activities to achieve compliance outcomes.
