ClamAV : A GPL anti-virus toolkit for UNIX ClamAV is a powerful AntiVirus scanner focused towards integration with mail servers for attachment scanning. It provides a flexible and scalable multi-threaded daemon, a command line scanner, and a tool for automatic updating via the Internet. Clam AntiVirus is based on a shared library distributed with the Clam AntiVirus package, which you can use with your own software. Most importantly, the virus database is kept up to… ClamAV
QualysGuard : A web-based vulnerability scanner Delivered as a service over the Web, QualysGuard eliminates the burden of deploying, maintaining, and updating vulnerability management software or implementing ad-hoc security applications. Clients securely access QualysGuard through an easy-to-use Web interface. QualysGuard features 5,000+ unique vulnerability checks, an Inference-based scanning engine, and automated daily updates to the QualysGuard vulnerability KnowledgeBase.
Sara : Security Auditor’s Research Assistant SARA is a vulnerability assessment tool that was derived from the infamous SATAN scanner. They try to release updates twice a month and try to leverage other software created by the open source community (such as Nmap and Samba).
Socat : A relay for bidirectional data transfer A utility similar to the venerable Netcat that works over a number of protocols and through a files, pipes, devices (terminal or modem, etc.), sockets (Unix, IP4, IP6 – raw, UDP, TCP), a client for SOCKS4, proxy CONNECT, or SSL, etc. It provides forking, logging, and dumping, different modes for interprocess communication, and many more options. It can be used, for example, as a TCP relay (one-shot… Socat
Whisker/libwhisker : Rain.Forest.Puppy’s CGI vulnerability scanner and library Libwhisker is a Perl module geared geared towards HTTP testing. It provides functions for testing HTTP servers for many known security holes, particularly the presence of dangerous CGIs. Whisker is a scanner that used libwhisker but is now deprecated in favor of Nikto which also uses libwhisker.
X-scan : A general scanner for scanning network vulnerabilities A multi-threaded, plug-in-supported vulnerability scanner. X-Scan includes many features, including full NASL support, detecting service types, remote OS type/version detection, weak user/password pairs, and more. You may be able to find newer versions available here if you can deal with most of the page being written in Chinese.
Fragroute/Fragrouter : A network intrusion detection evasion toolkit Fragrouter is a one-way fragmenting router – IP packets get sent from the attacker to the Fragrouter, which transforms them into a fragmented data stream to forward to the victim. Many network IDS are unable or simply don’t bother to reconstruct a coherent view of the network data (via IP fragmentation and TCP stream reassembly), as discussed in this classic paper. Fragrouter helps an attacker launch IP-based… Fragroute_Fragrouter
Nagios : An open source host, service and network monitoring program Nagios is a system and network monitoring application. It watches hosts and services that you specify, alerting you when things go bad and when they get better. Some of its many features include monitoring of network services (smtp, pop3, http, nntp, ping, etc.), monitoring of host resources (processor load, disk usage, etc.), and contact notifications when service or host problems occur and get resolved… Nagios
Yersinia : A multi-protocol low-level attack tool Yersinia is a low-level protocol attack tool useful for penetration testing. It is capable of many diverse attacks over multiple protocols, such as becoming the root role in the Spanning Tree (Spanning Tree Protocol), creating virtual CDP (Cisco Discovery Protocol) neighbors, becoming the active router in a HSRP (Hot Standby Router Protocol) scenario, faking DHCP replies, and other low-level attacks.
OpenBSD : The Proactively Secure Operating System OpenBSD is one of the only operating systems to treat security as their very highest priority. Even higher than usability in some cases. But their enviable security record speaks for itself. They also focus on stability and fight to obtain documentation for the hardware they wish to support. Perhaps their greatest achievement was creating OpenSSH. OpenBSD users also love [pf], their firewall tool.