Technical Information

Brief overview of the risk:
This security update resolves a privately reported vulnerability in Microsoft Lync. The vulnerability could allow remote code execution if an attacker shares specially crafted content, such as a file or program, as a presentation in Lync or Communicator and then convinces a user to accept an invitation to view or share the presentable content. In all cases, an attacker would have no way to force users to view or share the attacker-controlled file or program. Instead, an attacker would have to convince users to take action, typically by getting them to accept an invitation in Lync or Communicator to view or share the presentable content.
Detailed Information on the risk:

A remote code execution vulnerability exists when the Lync control attempts to access an object in memory that has been deleted. An attacker could exploit the vulnerability by convincing a target user to accept an invitation to launch specially crafted content within a Lync or Communicator session. An attacker who successfully exploited this vulnerability could gain the same user rights as the current user.

Further information on this exploit is available at : MS13-041