How to Protect Yourself From the "Here You Have" Virus

A harmful new computer worm infested the computers of large companies and federal agencies through an e-mail attack Thursday, bringing down such major companies as Disney, NASA, Comcast and more.

The worm disguises itself as a benign e-mail message with the subject line "here you have," and replicates itself by tricking you into clicking a link in the e-mail message's body. Then it can disable anti-virus products stored on your computer and send copies of the original, dangerous message to all the contacts in your e-mail address book.

Once the virus infests a computer, it can also spread to the local network -- which can include home and office computers -- surreptitiously copying itself to the shared hard drives of machines.

The threat is rapidly spreading through the enormous quantity of e-mail messages it has generated, said Internet security companies Norton and McAfee Labs, which have detected that many e-mail servers have ground to a halt due to the sheer volume of wire-clogging spam. The Department of Homeland Security's Computer Emergency Readiness Team (US-CERT) even weighed in on the worm, with advice for users.

“US-CERT is in the process of collecting and analyzing samples of the malware and has developed and disseminated mitigation strategies,” spokeswoman Amy Kudwa said. “Basic cyber security practices and hygiene are essential to maintaining the security of networks and individual computers.”

US-CERT recommends that you take more caution with your e-mail than usual, advising not to click on links in unsolicited e-mails, to install anti-virus software and frequently update it, and to turn off an option on your computer that automatically downloads attachments.

Security experts from Norton advise additional, more extreme steps you can take, such as disabling network sharing and disconnecting infected computers from the local network. If you've already gotten a "here you have" e-mail, the company suggested blocking outbound traffic to the domains or IP addresses contained in the e-mail to prevent users from connecting to distribution sites to download.

But the easiest way to protect yourself from this and other viruses is the simplest: Make sure you're running an anti-virus program and make sure it's up to date. security analyst Neil J. Rubenking agreed, stressing the importance of your own actions in keeping you safe.

"People! DO NOT click links in e-mail messages from unknown people. DO NOT even click links in e-mail messages from your friend, since the real source of the message might be a virus. DO keep your computer protected with an antivirus or a security suite," he wrote in an entry on the Security Watch blog.

"That way if you click the wrong link in a fit of weakness, you'll still be protected from whatever new threat replaces 'here you have,'" he pointed out.