A vulnerability classified as critical has been found in Apache Struts up to 2.3.15. This affects an unknown function of the component DefaultActionMapper. The manipulation of the argument action: / redirect: / redirectAction: with an unknown input leads to a buffer overflow vulnerability. This is going to have an impact on confidentiality, integrity, and availability.
The weakness was disclosed 07/16/2013 by Takeshi Terada with Mitsui Bussan Secure Directions as confirmed advisory (Website). The advisory is shared for download at struts.apache.org. The public release has been coordinated in cooperation with Apache. This vulnerability is uniquely identified as CVE-2013-2251 since 02/19/2013. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details and a public exploit are known.
A public exploit has been developed by Takeshi Terada and been published immediately after the advisory. It is declared as proof-of-concept. The exploit is shared for download at struts.apache.org. We expect the 0-day to have been worth approximately $25k-$50k. The vulnerability scanner Nessus provides a plugin with the ID 68981 (Apache Struts 2 'action:' Parameter Arbitrary Remote Command Execution), which helps to determine the existence of the flaw in a target environment. It is assigned to the family CGI abuses.
Upgrading to version 2.3.15.1 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability.