Microsoft Lync for Mac CVE-2017-0129 SSL Certificate Validation Security Bypass Vulnerability

Description

Microsoft Lync for Mac is prone to a security-bypass vulnerability that affects the IP-HTTPS server component. Successful exploits may allow attackers to perform man-in-the-middle attacks or impersonate trusted clients, which will aid in further attacks.

Technologies Affected

• Microsoft Lync for Mac 2011

Recommendations

Block external access at the network boundary, unless external parties require service.
If global access isn’t needed, filter access to the affected computer at the network boundary. Restricting access to only trusted computers and networks might greatly reduce the likelihood of exploits.

Deploy network intrusion detection systems to monitor network traffic for malicious activity.
Deploy NIDS to monitor network traffic for signs of anomalous or suspicious activity. This includes but is not limited to unexplained incoming and outgoing traffic. This may indicate exploit attempts or activity that results from successful exploits.

Updates are available. Please see the references or vendor advisory for more information.