Symantec is working on a solution for an elevation of privileges that could occur with corporate clients.  The retail versions (e.g., NAV 2006) are not impacted by this issue.  Users should be cautious in email and website visitations until this issue is resolved.

Corporate Symantec Anti-Virus Client vulnerability
http://www.symantec.com/avcenter/security/Content/2006.05.25.html

Internet Storm Center Information
http://www.incidents.org/diary.php?storyid=1364

PRODUCTS IMPACTED
Symantec Client Security 3.1 a  
Symantec Antivirus Corporate Edition 10.1

As best practice, Symantec strongly recommends the following:

* Restrict access to administration or management systems to privileged users only, with additional restricted access to the physical host system(s) if possible.

* Keep all operating systems and applications updated with the latest vendor patches.

* Follow a multi-layered approach to security. Run both firewall and antivirus applications, at a minimum to provide multiple points of detection and protection to both inbound and outbound threats.

* Be cautious visiting unknown or untrusted websites or following unknown URL links.

* Do not open attachments or executables from unknown sources or that you didn't request or were unaware of. Always err on the side of caution. Even if the sender is known, the source address may be spoofed.