The remote host is missing an update to libpam-krb5 announced via advisory USN-719-1.
Details follow:
It was discovered that pam_krb5 parsed environment variables when run with setuid applications. A local attacker could exploit this flaw to bypass authentication checks and gain root privileges. (CVE-2009-0360)
Derek Chan discovered that pam_krb5 incorrectly handled refreshing existing credentials when used with setuid applications. A local attacker could exploit this to create or overwrite arbitrary files, and possibly gain root privileges. (CVE-2009-0361)
Solution: The problem can be corrected by upgrading your system to the following package versions:
Ubuntu 8.04 LTS: libpam-krb5 3.10-1ubuntu0.8.04.1
Ubuntu 8.10: libpam-krb5 3.10-1ubuntu0.8.10.1
In general, a standard system upgrade is sufficient to effect the necessary changes.