Covering the wide range of technologies implemented by contemporary malware programs such as rootkits, keyloggers, spyware, adware, backdoors, and network and mail worms, this practical guide for system administrators and experienced users covers approaches to computer investigation and how to locate and destroy malicious programs without using antiviral software. Examples such as protocol fragments, operating principles of contemporary malicious programs, and an overview of specialized software for finding and neutralizing malware are presented.