How to detect audit data tampering

Audit logs are critical for security analysis, compliance, and forensic investigations. However, tampering with these logs can significantly compromise their integrity, making it difficult to detect malicious activity. Attackers may clear or manipulate logs to erase traces of their actions, disrupt incident response efforts, and evade regulatory scrutiny. Detecting audit data tampering is essential to maintaining the credibility of your logs and ensuring the security of your environment.

Let's look at an example

An attacker might disable or clear Windows event logs to cover up unauthorized actions, such as lateral movement or data exfiltration, leaving no evidence for investigation. This tampering not only complicates threat detection but also hinders compliance audits.

Relevant MITRE ATT&CK tactics and techniques

Tactics: Defense Evasion (TA0005) and Discovery (TA0007)

Techniques: Indicator Removal on Host (T1070), Indicator Removal on Host: Clear Windows Event Logs (T1070.001), Windows Services (T1546.003), Impair Defenses (T1562), Disable or Modify System Logging (T1562.006), Command and Scripting Interpreter (T1059)

So how do you mitigate these attacks?

Log360 provides an effective solution to detect audit log tampering through comprehensive monitoring and predefined alerts. The system can track and trigger alerts for key events related to the tampering of logs, such as the clearing of Windows event logs. Additionally, file integrity monitoring can be configured to ensure the integrity of audit log files.

Monitor key events

To detect potential audit data tampering, monitor the following events that indicate suspicious activity:

• Sysmon Driver Unloaded: This event occurs when the sysmon driver is removed, which may indicate an attempt to disable monitoring.
• Event Logs Cleared: This event is logged when audit logs are manually or programmatically erased, potentially to hide malicious activity.
• Event Tracing Disabled: This event is generated when event tracing is turned off, which could signal an attempt to evade logging.
• Audit Logs Tampered: This event is triggered when modifications to log integrity are detected, suggesting possible unauthorized changes.

Next steps after detection

• Attempt to retrieve any deleted data.
• Investigate the user who tampered with the data and take necessary actions, such as revoking permissions or changing passwords.
• Conduct an impact analysis to assess the extent of the breach and the potential damage.

Next steps

• Configure alerts: Set up alerts in Log360 for when events like Event Logs Cleared or Sysmon Driver Unloaded are detected.
• Implement file integrity monitoring: Set up file integrity monitoring on audit log directories to track any changes to the log files.
• Investigate alerts: Use Log360's incident investigation tools to dig deeper into the alerts and analyze the root cause.
• Review and strengthen security measures: Reassess the system’s security posture to prevent future tampering and improve log protection.

Log360 not only helps you detect audit log tampering but also offers comprehensive monitoring capabilities across various platforms, ensuring your security logs are never tampered with and remain trustworthy. With its predefined alerts, real-time monitoring, and correlation analysis, Log360 enables proactive detection and fast response to potential log manipulation, helping you safeguard your environment and ensure compliance with security standards.