Microsoft Office is prone to a remote code-execution vulnerability. An attacker can leverage this issue to execute arbitrary code in the context of the affected application. Failed exploit attempts will likely result in denial-of-service conditions.
Filter access to the affected computer at the network boundary if global access isn't required. Restricting access to only trusted computers and networks might greatly reduce the likelihood of exploits.
Deploy NIDS to monitor network traffic for anomalous or suspicious activity. Monitor logs generated by NIDS and by the server itself for evidence of attacks against the server.
To reduce the likelihood of successful exploits, never handle files that originate from unfamiliar or untrusted sources.
Permitting access to vulnerable applications for trusted individuals only can reduce the risk of an exploit.
Updates are available. Please see the references or vendor advisory for more information.