psad-1.3.tar.gz

Port Scan Attack Detector (psad) is a collection of four lightweight daemons written in Perl and C that are designed to work with Linux firewalling code (iptables and ipchains) to detect port scans. It features a set of highly configurable danger thresholds (with sensible defaults provided), verbose alert messages that include the source, destination, scanned port range, begin and end times, TCP flags and corresponding nmap options, email alerting, and automatic blocking of offending IP addresses via dynamic configuration of ipchains/iptables firewall rulesets. In addition, for the 2.4.x kernels psad incorporates many of the TCP, UDP, and ICMP signatures included in Snort to detect highly suspect scans for various backdoor programs (e.g. EvilFTP, GirlFriend, SubSeven), DDoS tools (mstream, shaft), and advanced port scans (syn, fin, Xmas) which are easily leveraged against a machine via nmap. Psad also uses packet TTL, IP id, TOS, and TCP window sizes to passively fingerprint the remote operating system from which scans originate. Changelog available here.