Currently (2006-2007), rootkits are the number 1 threat on most people’s horizons. Surprisingly, most of the current offerings that specifically target rootkits are freeware or open source. This list includes mainly generic anti-rootkit tools that are capable of detecting unknown rootkits rather than detecting only specific rootkits using only signature methods. All antiviruses and antispyware can detect rootkits by signature (before the rootkit has infected the system), and many have incorporated the tools on this page (see standalone scanners by conventional antivirus companies) so they have a shot at detecting even rootkits that have started and infected the system.