Microsoft Antivirus Engine is prone to an integer-overflow vulnerability when the application processes maliciously crafted files. This issue is currently being exploited via Portable Document Files (PDF), but other Microsoft applications are also reported vulnerable. An attacker could exploit this issue by enticing a victim into receiving or opening a malicious Office file. If the vulnerability is successfully exploited, this could result in the execution of arbitrary code in the context of the currently logged-in user.
Deploy network intrusion detection systems to monitor network traffic for malicious activity.
Deploy NIDS to monitor network traffic for signs of suspicious or anomalous activity. This may help detect malicious actions that an attacker may take after successfully exploiting vulnerabilities in applications. Review all applicable logs regularly.
Do not accept or execute files from untrusted or unknown sources.
Users should never accept files from untrusted or unknown sources, because they may be malicious in nature. Avoid opening email attachments from unknown or questionable sources.
Do not follow links provided by unknown or untrusted sources.
Users should avoid websites of questionable integrity. Never follow links supplied by unknown or untrusted sources.
Implement multiple redundant layers of security.
Since this issue may be leveraged to execute code, we recommend memory-protection schemes, such as non-executable stack/heap configurations and randomly mapped memory segments. This tactic may complicate exploits of memory-corruption vulnerabilities.
Microsoft has released automatic updates and an advisory for this issue; please see the reference section for more information.