New variant of Klez worm detected

A new variant of a worm that takes advantage of vulnerabilities in unpatched Microsoft Internet Explorer and Outlook Express software is spreading in the wild, antivirus vendors warned.

The mass mailing Win32.Klez.H@mm worm is a variant of the Klez worm that was first reported in October. Like its predecessors, the new version propagates through e-mail and attempts to copy itself through files that can be shared over a network. The worm uses random subject lines, the text within a message and attachment file names to try to get users to launch it.

Once launched, the worm copies itself to all addresses in the Windows address book and attempts to disable any antivirus software and processes that may be installed on a system.

When the Klez.H attachment is opened, it also will often drop a copy of a virus called W32.Elkern, which infects files that can be shared over a network and mapped drives and can cause systems to crash if activated.

What is new with Klez.H is its apparent ability to spread more widely, said Sharon Ruckman, director of Symantec Corp.'s security response team.

The subject lines and message bodies, for instance, have been expanded and made even more random than previous versions, she said. The virus also seems to have been designed to stop or disable a greater range of antivirus tools than older versions. In addition, the Elkern virus it carries has been modified to do more damage, Ruckman said.

Companies that are currently patched with the latest antivirus software should be protected against the virus, she said. Symantec is rating the virus as a "medium" risk.

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Jaikumar Vijayan

Computerworld
Show Comments

Brand Post

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Aysha Strobbe

Microsoft Office 365/HP Spectre x360

Microsoft Office continues to make a student’s life that little bit easier by offering reliable, easy to use, time-saving functionality, while continuing to develop new features that further enhance what is already a formidable collection of applications

Michael Hargreaves

Microsoft Office 365/Dell XPS 15 2-in-1

I’d recommend a Dell XPS 15 2-in-1 and the new Windows 10 to anyone who needs to get serious work done (before you kick back on your couch with your favourite Netflix show.)

Maryellen Rose George

Brother PT-P750W

It’s useful for office tasks as well as pragmatic labelling of equipment and storage – just don’t get too excited and label everything in sight!

Cathy Giles

Brother MFC-L8900CDW

The Brother MFC-L8900CDW is an absolute stand out. I struggle to fault it.

Luke Hill

MSI GT75 TITAN

I need power and lots of it. As a Front End Web developer anything less just won’t cut it which is why the MSI GT75 is an outstanding laptop for me. It’s a sleek and futuristic looking, high quality, beast that has a touch of sci-fi flare about it.

Emily Tyson

MSI GE63 Raider

If you’re looking to invest in your next work horse laptop for work or home use, you can’t go wrong with the MSI GE63.

Featured Content

Product Launch Showcase

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?