Post-Incident Forensic Data Reconstruction

In this lesson, you will learn how to synthesize fragmented audit logs and change data records to reconstruct the precise sequence of events during a data breach.

Reconstructing the Timeline

When a security incident occurs, your audit logs act as the database's "black box." Forensic reconstruction is the process of correlating disparate data points—such as SQL Injection patterns, Administrative Access logs, and Change Data Capture (CDC) entries—to create a chronological narrative of an attacker's movement within your system.

The Forensic Workflow

To perform a reconstruction, you must bridge the gap between "what happened" and "who did it." The process generally follows these steps:

1. Identify the Breach Vector: Look at your SQL Injection logs to find the initial entry point. If a query injected malicious input, correlate the session_id and timestamp with your audit trail.
2. Trace Administrative Escalation: Use your Monitoring Administrative Access logs to see if the attacker successfully escalated privileges. Look for GRANT statements or suspicious SET ROLE commands executed during the window of compromise.
3. Map Data Exfiltration via CDC: This is the most critical step. Since standard audit logs might only show who queried what, use Change Data Capture (CDC) to see if data was modified or deleted to cover tracks.

Consider a scenario where an attacker updates a user’s permissions. Your audit table audit_log_events might look like this:

SELECT timestamp, user_identity, command_text 
FROM audit_log_events 
WHERE timestamp BETWEEN '2023-10-01 10:00:00' AND '2023-10-01 10:30:00'
ORDER BY timestamp ASC;

By joining this with your CDC records, you can see not just the command issued, but the actual state of the rows before and after the unauthorized modification. This allows you to quantify exactly what data was altered, effectively "undoing" the attacker's obfuscation to see the true impact on your schema.

Effective forensic reconstruction requires that your logs have not been tampered with; therefore, you must rely on the Integrity Controls for Audit Logs we discussed previously to ensure your reconstruction is based on immutable evidence rather than modified history.

Key Takeaway: Post-incident reconstruction relies on correlating audited query text with state-change data from CDC to map the attacker's trajectory and calculate the true scope of the data breach.