Late on July 10, Microsoft released a disclosing that they were aware of a zero-day attack in the wild. This attack exploits a previously unpatched Internet Explorer vulnerability (CVE-2013-3163). It’s interesting that the vulnerability was just patched in this month’s Patch Tuesday (July 9), which is perhaps only a coincidence. Although we do not know how long ago the attack began, we do have the right now. (Apply the Microsoft patch if you haven’t done so.)
McAfee Labs rapidly responded to the threat. While digging into the exploitation process, we realized that this attack leverages the same exploitation technology that we were first to identify in an Adobe Flash zero-day attack in February. We call the new exploitation technology the Flash Vector exploitation. As highlighted in , we made a fairly accurate prediction:
More important, the technique looks like a common exploitation approach to Flash Player. The vulnerability actually doesn’t help much–just overwriting few bytes that are considered as a field of “element number” for a specific ActionScript object. These traits show that the exploitation technique is not limited to this particular Flash vulnerability; it may apply to other Flash or non-Flash vulnerabilities.
Both of these attacks leverage a weakness inside Flash Player’s custom heap management, especially, for the heap management of ActionScript “Vector.<>” objects. During our analysis, we also found some minor differences between these two attacks: