Technical Information

Brief overview of the risk:
This security update resolves one publicly disclosed vulnerability in a Microsoft Office shared component that is currently being exploited. The vulnerability could allow security feature bypass if a user views a specially crafted webpage in a web browser capable of instantiating COM components, such as Internet Explorer. In a web-browsing attack scenario, an attacker who successfully exploited this vulnerability could bypass the Address Space Layout Randomization (ASLR) security feature, which helps protect users from a broad class of vulnerabilities. The security feature bypass by itself does not allow arbitrary code execution. However, an attacker could use this ASLR bypass vulnerability in conjunction with another vulnerability, such as a remote code execution vulnerability that could take advantage of the ASLR bypass to run arbitrary code.
Detailed Information on the risk:

A security feature bypass exists in an Office shared component that does not properly implement Address Space Layout Randomization (ASLR). The vulnerability could allow an attacker to bypass the ASLR security feature, after which the attacker could load additional malicious code in the process in an attempt to exploit another vulnerability.

Further information on this exploit is available at : MS13-106