According to a confirmation by Microsoft late last night, a new zero day vulnerability has been found to affect every version of Internet Explorer. In other words—over a quarter of the entire browser market.
Attacks taking advantage of the vulnerability are largely targeting IE versions 9, 10, and 11 in something called a “use after free” attack. Essentially, the attack corrupts data as soon as memory has been released, most likely after users have been lured to phony websites. Microsoft explains:
The vulnerability exists in the way that Internet Explorer accesses an object in memory that has been deleted or has not been properly allocated. The vulnerability may corrupt memory in a way that could allow an attacker to execute arbitrary code in the context of the current user within Internet Explorer. An attacker could host a specially crafted website that is designed to exploit this vulnerability through Internet Explorer and then convince a user to view the website.
Microsoft is currently investigating the issue and will likely release an out-of-cycle security patch to take care of the problem. Let’s just hope it comes soon, because according to security firm Fire Eye, this means that about 26 percent of the entire browser market is at risk.