Security holes in Microsoft"s Internet Explorer browser 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, California-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.