McAfee VirusScan for Mac (Virex) before 7.7 patch 1 has weak permissions (0666) for /Library/Application Support/Virex/VShieldExclude.txt, which allows local users to reconfigure Virex to skip scanning of arbitrary files.
http://www.vupen.com/english/advisories/2007/0777
http://www.securitytracker.com/id?1017707
http://www.securityfocus.com/archive/1/461485/100/0/threaded
http://securityreason.com/securityalert/2342