Microsoft Internet Information Services (IIS) is prone to a remote code-execution vulnerability that can be exploited through malicious input to vulnerable ASP pages. A successful exploit of this vulnerability could let remote attackers execute arbitrary code in the context of the Worker Process Identity, which by default has Network Service privileges.
Block external access at the network boundary, unless external parties require service.
If possible, block external access at the network boundary. Permit access for trusted networks and hosts only.
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 requests that include NOP sleds and unexplained incoming and outgoing network traffic. This may indicate exploit attempts or activity that results from successful exploits.
Implement multiple redundant layers of security.
Various memory protection schemes (such as nonexecutable and randomly mapped memory segments) may hinder an attacker's ability to exploit this vulnerability to execute arbitrary code.
Microsoft has released a security bulletin to address this vulnerability. Please see the references for details.