Microsoft has released a temporary fix for a zero-day vulnerability in Internet Explorer 8, which was used by hackers in a prominent attack against the U.S. Department of Labor’s website.
The problem is particularly dangerous since it can allow an attacker to install malware merely by visiting a tampered webpage. Microsoft is still working on a patch, wrote Dustin Childs, group manager for the company’s Trustworthy Computing division.
“Customers should apply the Fix it or follow the workarounds listed in the advisory to help protect against the known attacks,” Childs said in a statement.
The vulnerability is described as a problem in the way IE “accesses an object in memory that has been deleted or has not been properly allocated.” IE versions 6, 7, 9 and 10 are not affected.
Microsoft calls the fix “CVE-2013-1347 MSHTML Shim Workaround.” The company normally issues updates for its products on the second Tuesday of the month, but will issue an out-of-schedule patch if the problem is deemed serious enough.
Security vendors Invincea and AlienVault found that hackers planted attack code within a U.S. Labor Department webpage with information on toxic substances at U.S. Department of Energy facilities.
The code redirected people to another infected page within the site, which then attempted to exploit the IE 8 vulnerability. AlienVault said the hacking campaign appeared similar to a known China-based one called “DeepPanda,” which installed remote-access trojans (RATs).
A large Fortune 500 company was attacked in December 2011 by DeepPanda, AlienVault said.