Code for both of the vulnerabilities has been published, but currently there are no reports of attackers who have taken advantage of these flaws, the SANS Internet Storm Center, which monitors network threats, said in an advisory released Wednesday.
The flaw that affects both IE and Firefox is related to the handling of the object.documentElement.outerHTML property, according to the advisory. That technology is used to access documents delivered from one Web site to another.
Attackers could exploit the IE or Firefox flaw using what's known as cross-site scripting, allowing them to view the contents of one open browser from a second browser open on the user's system, said Monty Ijzerman, senior manager of McAfee's Global Threat Group. The attackers, as a result, could swipe sensitive information, such as online banking data, from one of the sites, for example.
"We consider this flaw less serious than the other IE flaw," Ijzerman said. "A user would have to have multiple browsers open, and the information on the site would have to be relevant to what the attacker wanted."
The second flaw is related to the way HTA applications are processed. A user could be tricked into double-clicking on a malicious file and remote code could be executed, Ijzerman said. An attacker could exploit the vulnerability to read files on a system or install rootkits, which make system changes to hide another piece of possibly malicious software.
The two IE security flaws come as Microsoft releases its final beta version of IE 7, which is designed to offer more security features.
Microsoft said it is investigating the issue and has yet to hear of any attackers exploiting the reported vulnerabilities.
Mozilla was not immediately available for comment.
"We consider this flaw less serious than the other IE flaw," Ijzerman said. "A user would have to have multiple browsers open, and the information on the site would have to be relevant to what the attacker wanted."
How often does one have only one browser window open when using IE. Of course if you're using Firefox then you probably would have only one open unless it was a bank account which automatically opens a new window. Wouldn't be what the attackers wanted now would it? Not banking details.
Ijzerman, you are not a genius of any persuasion!