During an intrusion, an intruder leaves signs of his actions in various system logs. Without reliable logs, it could be very difficult to figure out how the attacker got in, or where the attack came from. This information is crucial in analyzing the incident. It is evident that the logs are a valuable audit trail that should be well protected.
Of course, when an intruder gets in to the system, they will try to remove all traces. So, how can we stop an intruder from removing evidence?