Linux admins,

By the time an incident reaches your team, the first question is usually what happened? The answer is often already somewhere on the system. This week's stories focus on protecting and using that evidence, from recognizing when logs have been altered to building repeatable detections that identify suspicious behavior before it becomes a larger problem.  Effective investigations depend on reliable evidence, not guesswork.

Yours in Open Source,

Dv Signature Newsletter 2026 Esm W100

Dave Wreski, Founder

Missing Log Entries Can Be an Indicator

Attackers don't always erase every trace of their activity. Removing a handful of authentication records, clearing shell history, or modifying log files is often enough to disrupt an investigation and slow responders down. Understanding what normal log activity looks like, validating log integrity, and correlating events across multiple sources can expose attempts to manipulate evidence even when individual log files appear incomplete. During incident response, missing data is often just as valuable as the data that's still there.

→ Learn how to investigate Linux log manipulation

Detection Becomes More Effective When It's Repeatable

Every investigation should strengthen the next one. Detection as Code allows teams to turn investigation findings into reusable detection rules that can be version-controlled, tested, and continuously improved alongside the rest of their infrastructure. Instead of manually searching for the same indicators each time suspicious activity appears, organizations can build consistent detections that identify those behaviors across every Linux system they manage.

→ Read about Detection as Code for Linux