distributed.net is a loosely knit group of computer users from all of the world that is taking up challenges requiring lots of computing power (most notably the RC5, DES, and OGR cracking contests). It is simple to participate in the challenges by downloading and running their client software (which uses idle CPU time to complete its tasks).
Ettercap is a network sniffer/interceptor/logger for ethernet LANs. It supports active and passive dissection of many protocols (even ciphered ones, like SSH and HTTPS). Data injection in an established connection and filtering on the fly is also possible, keeping the connection synchronized. Many sniffing modes were implemented to give you a powerful and complete sniffing suite. Plugins are supported. It has the ability to check whether you are in a switched LAN or not, and to use OS fingerprints (active or passive) to let you know the geometry of the LAN.
TEA Total is a collection of extremely small encryption tools. At the heart of TEA Total is the TEA (Tiny Encryption Algorithm): a fast and secure 128-bit private key algorithm which was developed and placed in the public domain by David Wheeler and Roger Needham of the Cambridge Computer Laboratory.
SecurityFocus ARIS Extractor is a sophisticated Intrusion Detection System (IDS) log analyzer and reporting system, integrated with the SecurityFocus ARIS web site. It allows administrators to upload Intrusion Detection System (IDS) logs to the SecurityFocus ARIS Web site, producing sophisticated reporting, and research attacks and events. By filtering out insignificant or benign data and converting it to a common (XML) format, ARIS extractor streamlines incident reporting for both security professionals and home users, allowing IDS operators to focus only on relevant attacks and incidents. It allows you to analyze and archive logged incidents, cross reference incidents/attacks with the SecurityFocus Vulnerability Database, look up contact information for offending IP addresses, generate personal incident statistics and reports, automatically identify and report important incidents, reduce the amount of time spent parsing IDS logs, and generate daily summary reports, delivered by email (optional). All of this is done without revealing any information that could be used to discern your identity. It can be configured to obfuscate IP addresses, names, and other pertinent details before submitting them to the ARIS Analyzer web site. It supports Snort, Cisco Secure IDS, Dragon, NetProwler, RealSecure, BlackICE Defender, and ICEPac.
OpenVPN is a robust and highly configurable VPN (Virtual Private Network) daemon which can be used to securely link two or more private networks using an encrypted tunnel over the Internet. OpenVPN's principal strengths include wide cross-platform portability, excellent stability, support for dynamic IP addresses and NAT, adaptive link compression, single TCP/UDP port usage, a modular design that offloads most crypto tasks to the OpenSSL library, and relatively easy installation that in most cases doesn't require a special kernel module.
Firewall Builder for PIX hides the complexity of PIX command line interface and automatically configures options and parameters that usually make manual configuration a real chore. With this module, the same workstation running Firewall Builder can create and manage security policy on Cisco PIX or FWSM firewalls, as well as on firewalls built with iptables, OpenBSD pf, or ipfilter.