Yahoo e-mail under worm attack, warns Symantec

A mass-mailing worm that exploits a vulnerability in Yahoo's Web e-mail is making the rounds, security vendor Symantec reported Monday.

A mass-mail worm that exploits a vulnerability in Yahoo's Web e-mail is making the rounds but the impact appears to be low, security vendor Symantec said Monday.

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 Kevin 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 (Hypertext Markup Language) e-mail to run in the users' browsers. Yahoo 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.

When activated, the worms then sends itself to other users in the victim's address book who also use Yahoo e-mail with the suffixes of @yahoo.com or @yahoogroups.com. The worm mimics a function within Yahoo'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 Yahoo 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 Yahoo's Web e-mail has not been fixed, users are advised to update virus and firewall definitions and block any e-mail sent from av3@yahoo.com. The subject line of the e-mail with the worm says "New Graphic Site," and the body says "this is test."

Yahoo officials could not immediately be reached for comment.

Join the PC World newsletter!

Error: Please check your email address.

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Jeremy Kirk

IDG News Service
Show Comments

Essentials

Microsoft L5V-00027 Sculpt Ergonomic Keyboard Desktop

Learn more >

Lexar® JumpDrive® S57 USB 3.0 flash drive

Learn more >

Mobile

Lexar® JumpDrive® S45 USB 3.0 flash drive 

Learn more >

Exec

Audio-Technica ATH-ANC70 Noise Cancelling Headphones

Learn more >

Lexar® Professional 1800x microSDHC™/microSDXC™ UHS-II cards 

Learn more >

Lexar® JumpDrive® C20c USB Type-C flash drive 

Learn more >

HD Pan/Tilt Wi-Fi Camera with Night Vision NC450

Learn more >

Budget

Back To Business Guide

Click for more ›

Most Popular Reviews

Latest News Articles

Resources

PCW Evaluation Team

Michael Hargreaves

Windows 10 for Business / Dell XPS

I’d happily recommend this touchscreen laptop and Windows 10 as a great way to get serious work done at a desk or on the road.

Aysha Strobbe

Windows 10 / HP Spectre

Ultimately, I think the Windows 10 environment is excellent for me as it caters for so many different uses. The inclusion of the Xbox app is also great for when you need some downtime too!

Mark Escubio

Windows 10 / Lenovo Yoga

For me, the Xbox Play Anywhere is a great new feature as it allows you to play your current Xbox games with higher resolutions and better graphics without forking out extra cash for another copy. Although available titles are still scarce, but I’m sure it will grow in time.

Kathy Cassidy

STYLISTIC Q702

First impression on unpacking the Q702 test unit was the solid feel and clean, minimalist styling.

Anthony Grifoni

STYLISTIC Q572

For work use, Microsoft Word and Excel programs pre-installed on the device are adequate for preparing short documents.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?