Yes! Learn to Love your Log file, it tells everything you want to hear.
Even a Clever thief always leave his fingerprints anywhere at the crime scene, in the same way most of the malicious exploit and intruders leave their fingerprints or say footprint all over the Log file. If the log file management system was crafted correctly, it will tell you everything about the actual attack
You can expect a good result by set up an event management system that will collect, filter, and analyze your log file data, then prioritize and generate alerts.
Download this PDF(published by NIST U.S. Department of Commerce) and Read this whole story from Introduction to Operational Process.