Attrition.org - Attrition is an eclectic collection of internet and computer security resources.
Crewl Underground Madness - Belgian group specialized in computer and network (in)security, hacking, coding and phreaking.
Cult of the Dead Cow - Offers team background, tools and BackOrifice downloads, and news archive.
CyberArmy - Internet security group focusing on internet deregulation. Also provides tools for anonymity, password cracking, port scanning, remote administration and firewalls.
CyberWarrior Main Base - CyberWarrior specializes in tutorials, downloads ,and other information.
The Dark Side - Offers tutorials and articles on security related content, hacking, cracking, and network exploits.
Eleventh Alliance - Offers details regarding select viruses, overflow and security exploits, bios tools, and crytography. Also features book reviews on assembly programming and computer security.
HackHull - Group of hackers in the United Kingdom. Information about meetings, projects, and links to personal pages.