This zero-day is a remote code execution vulnerability, which may corrupt memory and allow an attacker to execute arbitrary code in the context of the current user within Internet Explorer.
The vulnerability is easily triggered, and requires the targets to simply visit a specially crafted website hosting the exploit, or websites that accept or host user-provided content or advertisements that could exploit the vulnerability. It's only a matter of luring users to such a site.
Only Internet Explorer 9 and Internet Explorer 10 are affected by this vulnerability - although the spotted attacks concentrated on compromising only IE 10 users.
IE versions 6, 7, 8 and 11 are not affected, and Microsoft has been advising users to protect themselves by upgrading to the latest version made available.
Those who can't update at this time, can download a specific Fix it or install the Enhanced Mitigation Experience Toolkit (EMET), as the exploit prevents itself from running if it detects EMET on the target computer.
"On completion of this investigation, Microsoft will take the appropriate action to protect our customers, which may include providing a solution through our monthly security update release process, or an out-of-cycle security update, depending on customer needs," they concluded.