Kerberos 5 su (k5su) in FreeBSD 4.4 and earlier relies on the getlogin system call to determine if the user running k5su is root, which could allow a root-initiated process to regain its privileges after it has dropped them.Referencesftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-02:07.k5su.aschttp://www.securityfocus.com/bid/3919http://www.iss.net/security_center/static/7956.php
