Microsoft Outlook is prone to a remote code-execution vulnerability because the application fails to properly handle malformed iCal requests. A remote attacker can exploit this issue to execute arbitrary code with the privileges of unsuspecting users. A successful exploit may aid in the remote compromise of the underlying computer.
Run all software as a nonprivileged user with minimal access rights.
Running the affected Outlook client as a user with least privileges possible may help mitigate the impact of a successful attack.
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. Monitor logs regularly for any signs of unusual activity, such as repeated crashes.
Implement multiple redundant layers of security.
Memory-protection schemes (such as non-executable stack/heap configurations and randomly mapped memory segments) may complicate the successful exploit of memory-corruption vulnerabilities.
Do not open email messages from unknown or untrusted individuals.
Users should never trust incoming email messages originating from unknown or untrusted sources.
Microsoft has released an advisory and fixes to address this issue. Please see the references for more information.