The Security Mentor

There's a new self-reproducing email affecting Yahoo! Mail. It spreads due to a bug in Yahoo's filterning that allows the email too much control over your browser. The mail will pretend to be from av3@yahoo.com.

While you wait for Yahoo to put in a real fix, you could try blocking email from av3@yahoo.com or email with the subject "New Graphic Site". This won't work for long: the people who write things like this can adapt easily.

A painful but more effective approach is to turn off Javascript. Yahoo mail should then tell you to turn Javascript back on or to switch to an older and less functional version of Yahoo! Mail. Do the latter. The problem is that when this problem is finally solved and it's safe to swtich Javascript back on, Yahoo! may not sense that you've done it. There's a conflict with Norton Internet Security, see, and -- stop, don't go away, if you think that's more trouble than it's worth then try the blocking approach mentioned above. Otherwise, if you can't get Yahoo! to realize you've turned Javascript back on and if you're running NIS, then log out of Yahoo! Mail, turn off NIS, log into Yahoo! Mail, and turn NIS back on. I am not making this up: credit to a user at wembasterworld.com named directrix.
UPDATE 6/13:
According to one report, Yahoo! has released a fix. This should take care of it automatically with no need for action on your part.