The Apache mod_isapi module can be forced to unload a specific library before the processing of a request is complete, resulting in memory corruption. This vulnerability may allow a remote attacker to execute arbitrary code.
The Apache HTTP server running on Windows platforms contains a flaw in mod_isapi which could enable an attacker to unload ISAPI.dll before request processing is complete. An attacker can send a specially-crafted request and RESET packet to the server, resulting in ISAPI.dll being unloaded. Additional requests can result in memory corruption.
This vulnerability affects Apache httpd versions 2.2.14, 2.2.13, 2.2.12, 2.2.11, 2.2.10, 2.2.9, 2.2.8, 2.2.6, 2.2.5, 2.2.4, 2.2.3, 2.2.2, 2.2.0, 2.0.63, 2.0.61, 2.0.59, 2.0.58, 2.0.55, 2.0.54, 2.0.53, 2.0.52, 2.0.51, 2.0.50, 2.0.49, 2.0.48, 2.0.47, 2.0.46, 2.0.45, 2.0.44, 2.0.43, 2.0.42, 2.0.40, 2.0.39, and 2.0.37.
A remote, unauthenticated attacker may be able to cause a denial of service condition or execute arbitrary code on the system with the privileges of the Apache process. Because the Apache service typically runs with SYSTEM privileges on Windows platforms, an attacker may be able to gain complete control of the system.
Apache credits Brett Gervasoni of Sense of Security for reporting the issue.