Symantec Backup Exec 11.0, 12.0, 12.5, 13.0, and 13.0 R2 does not validate identity information sent between the media server and the remote agent, which allows man-in-the-middle attackers to execute NDMP commands via unspecified vectors.
http://marc.info/?l=bugtraq&m=131489365508507&w=2
http://secunia.com/advisories/44698
http://securityreason.com/securityalert/8300