Detecting Intruders from log files and traces. Special Intruder Detection Systems (IDS) are now a market niche, and there are many products on the market. In this chapter we take a look at the more traditional ways of detecting intruders by investigating traces.
logs by applications (sendmail, ftp, httpd)
Administrative Tools Event Viewer (Security)
Users logging in at unusual hours
Unexplained time changes
Unusual error messages
Failed login attempts
Users logging in from unfamiliar sites