The Response Group Service in Microsoft Lync Server 2010 and 2013 and the Core Components in Lync Server 2013 do not properly handle exceptions, which allows remote attackers to cause a denial of service (daemon hang) via a crafted call, aka "Lync Denial of Service Vulnerability."
https://exchange.xforce.ibmcloud.com/vulnerabilities/95544
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2014/ms14-055
http://www.securitytracker.com/id/1030821