IE holes lead to AIM, dial-up attacks


Security holes in Microsoft's Internet Explorer have been exploited by hackers to hijack AOL instant messaging accounts and force unsuspecting Web surfers to run up massive phone bills, computer experts cautioned on Friday.

Some Internet Explorer users are also finding that malicious Web sites are secretly slipping Trojan programs onto their computers, which could prove an even more dangerous exploit, said Drew Copley, a research engineer at Aliso Viejo, Calif.-based eEye Digital Security, who discovered the original security vulnerability.

Such stealth programs can include keystroke loggers that record everything a person types or software to erase the hard drive, among other things, he said.

Microsoft has released a patch for the original hole, which was reported about a month ago, said Stephen Toulouse, security program manager for Microsoft's Security Response Center. The company is looking into what it says are variations of the original hole that have been discovered since then that the patch does not fix, Toulouse said.

"We will release a fix for the variations," he said.

Security experts are reporting the variations as new security holes, disclosed within the past three weeks and used for different types of attacks, Copley said.

Microsoft and eEye Digital Security said they have issued information for temporary workarounds.

In general, the attacks are accomplished by leading Internet Explorer users to a malicious Web site, either by sending an e-mail with a link to the Web page or distributing a link through instant messaging, Copley said.

When the Web site appears, it downloads code that can execute commands on its own onto the unsuspecting computer user's machine, Copley said.

An attacker has written a program that uses a security hole in Internet Explorer to hijack an already running AOL Instant Messenger account, changes the password and sends a message to the buddies list with a link to the malicious Web page, according to postings on the Bugtraq security e-mail list.

The Web site the posting listed as stealing the AIM passwords appeared to have been shut down.

An AOL Time Warner spokesman said the company was looking into the issue.

'Porn dialer' attack
Another attack is being accomplished by sending computer users to Web sites--typically porn sites--that change the computer's dial-up settings to an expensive long-distance phone number without the user knowing it, said Richard Smith, an independent Boston-based security researcher.

In the so-called "porn dialer" attack, victims are being charged as much as $5 a minute instead of paying their normal Internet service fee, he said.

A third type of attack steers computer users to pay-per-click Web sites, where the spam marketer gets paid each time someone goes to the Web site, Copley said.

"These kinds of bugs are really spooky" because they work in the background, undetected by the computer user, he said. "With these kind of holes, a lot of roaches crawl through."

Computer users can protect themselves by applying patches, following the workaround instructions, or changing their settings in Internet Explorer to prompt them before a Web site downloads programs that can execute on their own, Toulouse said.

Also on Friday, antivirus company Global Hauri of South Korea warned about a new medium-risk computer worm that spreads through Microsoft Network's MSN Messenger system, attempts to connect to a porn Web site and passes itself around to others in the victim's contact list.

Toulouse said Microsoft was looking into the matter.