psad – Intrusion Detection and Log Analysis with iptables


psad is a collection of three lightweight system daemons (two main daemons and one helper daemon) that run on Linux machines and analyze iptables log messages to detect port scans and other suspicious traffic. A typical deployment is to run psad on the iptables firewall where it has the fastest access to log data.

psad incorporates many signatures from the Snort intrusion detection system to detect probes for various backdoor programs (e.g. EvilFTP, GirlFriend, SubSeven), DDoS tools (mstream, shaft), and advanced port scans (FIN, NULL, XMAS) which are easily leveraged against a machine via nmap.

When combined with fwsnort and the Netfilter string match extension, psad is capable of detecting many attacks described in the Snort rule set that involve application layer data. In addition, psad makes use of various packet header fields associated with TCP SYN packets to passively fingerprint remote operating systems (in a manner similar to p0f) from which scans originate.

For more information, see the complete list of features offered by psad.

psad is developed around three main principles:

  • Good network security starts with a properly configured firewall.
  • A significant amount of intrusion detection data can be gleaned from firewalls logs, especially if the logs provide information on nearly every field of the network and transport headers (and even application layer signature matches as in Netfilter’s case).
  • Suspicious traffic should not be detected at the expense of trying to also block such traffic.

You can download psad v2.1.4 here:

psad-2.1.4.tar.gz (Source tar)
psad-2.1.4-1.i386.rpm (i386 binary RPM).

Or read more here.

Posted in: Countermeasures, Networking Hacking, Security Software

, , , ,


Latest Posts:


RandIP - Network Mapper To Find Servers RandIP – Network Mapper To Find Servers
RandIP is a nim-based network mapper application that generates random IP addresses and uses sockets to test whether the connection is valid or not with additional tests for Telnet and SSH.
Nipe - Make Tor Default Gateway For Network Nipe – Make Tor Default Gateway For Network
Nipe is a Perl script to make Tor default gateway for network, this script enables you to directly route all your traffic from your computer to the Tor network.
Mosca - Manual Static Analysis Tool To Find Bugs Mosca – Manual Static Analysis Tool To Find Bugs
Mosca is a manual static analysis tool written in C designed to find bugs in the code before it is compiled, much like a grep unix command.
Slurp - Amazon AWS S3 Bucket Enumerator Slurp – Amazon AWS S3 Bucket Enumerator
Slurp is a blackbox/whitebox S3 bucket enumerator written in Go that can use a permutations list to scan externally or an AWS API to scan internally.
US Government Cyber Security Still Inadequate US Government Cyber Security Still Inadequate
Surprise, surprise, surprise - an internal audit of the US Government cyber security situation has uncovered widespread weaknesses, legacy systems and poor adoption of cyber controls and tooling.
BloodHound - Hacking Active Directory Trust Relationships BloodHound – Hacking Active Directory Trust Relationships
BloodHound is for hacking active directory trust relationships and it uses graph theory to reveal the hidden and often unintended relationships within an AD environment.


One Response to psad – Intrusion Detection and Log Analysis with iptables

  1. Goodpeople September 22, 2008 at 6:59 am #

    a lightweight ids.. good news for home users..