vl4dZ is a system administrator who is into security and coding (Bash & C). He has written tools like Assh: The Anonymous Secure SHell, Fsnoop, GUChaos, Pwd-hash, and other useful sec tools.
Coded a simple Man-in-middle detection script.
He discovered two vulnerabilities in the X server Xorg and assigned with CVE-2011-4028 and CVE-2011-4029.
More of his disclosures and papers can be found here: http://vladz.devzero.fr/
http://packetstormsecurity.com/files/author/6366/
http://www.exploit-db.com/author/?a=1206
http://vladz.devzero.fr/