Microsoft Windows Media Service is prone to a remote stack-based buffer-overflow vulnerability because the application fails to perform adequate boundary checks on user-supplied data. Attackers can exploit this issue to execute arbitrary code within the context of the affected application. Failed exploit attempts will result in a denial-of-service condition. Update (April 21, 2010): Microsoft reports that the patch released as MS10-025 does not resolve this issue. Microsoft intends to release a new fix in the following week; this BID will be updated as more information emerges. Update (April 27, 2010): Updated MS10-025 includes a new fix.
Block external access at the network boundary, unless external parties require service.
Ensure that only trusted hosts and networks can connect to vulnerable servers by blocking access at network perimeters.
Run all software as a nonprivileged user with minimal access rights.
To reduce the impact of latent vulnerabilities, always run nonadministrative software as an unprivileged user with minimal access rights.
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 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.
The vendor has re-released an advisory and updates. Please see the references for details.