Info on the worm

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http://securityresponse.symantec.com/avcenter/venc/data/js.yamanner@m.

html

Worm Attacks E-Mail

A mass-mail worm that exploits a vulnerability in 's Web-based e-

mail is making the rounds but the impact appears to be low, security

vendor Symantec said today.

The worm, which Symantec calls JS.Yamanner@m, is different from

others in that a user merely has to open the e-mail to cause it to

run, said Hogan, senior manager for Symantec Security Response.

Mass-mail worms have usually been contained in an attachment with an

e-mail note encouraging a user to open it.

The worm, written in JavaScript, takes advantage of a vulnerability

that allows scripts embedded in HTML e-mail to run in the users'

browsers. users should be able to modify their settings to

block the zero-day exploit, Hogan said.

Symantec rated the worm a Level 2 threat, one notch above its least

harmful ranking. Hogan said the worm did not appear to be spreading

widely, and he did not anticipate the threat level rising.

How It Spreads

When activated, the worms then sends itself to other users in the

victim's address book who also use e-mail with the suffixes of

@ or . The worm mimics a function within

's Web mail called " Quickbuilder, " which allows a user to

add

contacts in an address book from received e-mail, Hogan said. The

process, however, is transparent to the victim, he said.

The harvested e-mail addresses are sent to a remote server. Users of

Mail Beta do not appear to be affected, Symantec said.

The worm also opens a browser that displays a Web page that does not

appear to contain malicious content.

Although 's Web e-mail has not been fixed, users are advised to

update virus and firewall definitions and block any e-mail from

ANYONE that has the subject line of the e-mail with the worm " New

Graphic Site, " and the body says " this is test " or

" Attachments " .