Three potential vulnerabilities affecting all Nortel VPN router models were flagged by the company this week. Nortel has issued patches for all three problems. Nortel adds that upgrading to VPN router software versions 6_05.140, 5_05.304 or 5_05.149 fixes the three issues it is reporting. (The upgrade secures the two diagnostic user accounts, closes the vulnerability in the Web manager and adds 3DES encryption to passwords). Software upgrades can be obtained at Nortel's site.

Spammers have stepped up efforts to use encrypted attachments to evade filtering systems, service provider Email Systems has reported.

The technique relies on the fact that many spam systems can't scan inside e-mails containing encrypted or password-protected attachments, and work out that they are not legitimate. Without a rule to block such attachments, most systems will pass on the e-mail to recipients, handing spammers an important victory in the battle to get spam through.

In recent weeks, Email Systems detected a small but steady stream of such spam emanating from bot-compromised hosts, containing a zipped-up version of the pervasive "Storm" bot-loading Trojan horse that plagued Internet users in January.