Apache has released an additional security advisory and updated software to address the vulnerabilities in Apache products using Apache Struts 2.
A vulnerability in the DefaultActionMapper component could allow an unauthenticated, remote attacker to execute arbitrary commands on the targeted system.
The vulnerability is due to insufficient sanitization of user-supplied input. An attacker could exploit this vulnerability by sending crafted requests consisting of Object-Graph Navigation Language (OGNL) expressions. An exploit could allow the attacker to execute arbitrary code on the targeted system.
Proof-of-concept code that exploits this vulnerability is publicly available.
Apache.org has confirmed this vulnerability and released updated software.
Products using Apache Struts versions 2.0.0 through 2.3.15 are vulnerable. As identified in the Cisco Security Advisory, the following Cisco products are vulnerable:
Cisco Identity Services Engine Software
Cisco Business Edition 3000 Software
Cisco Unified SIP Proxy
Cisco MXE 3500 (Media Experience Engine)
To exploit the vulnerability, the attacker may need access to trusted or internal networks to be able to transmit crafted requests to the targeted system. This access requirement could limit the likelihood of a successful attack.
The vendor report indicates that the vulnerability has been fixed by changing the DefaultActionMapper to sanitize action: prefixed information properly. The feature involved with redirect:/redirectAction: prefixed parameters was removed completely.
Reports indicate that this vulnerability is being exploited actively in the wild and are highly automated, which increases the likelihood of widespread attacks.
An unauthenticated, remote attacker could exploit the vulnerability to inject simple expressions or execute arbitrary commands on the targeted system. This could allow the attacker to gain sensitive information or inject server-side codes.
The vulnerability exists in a short-circuit navigation state change method of the DefaultActionMapper due to improper handling of parameters with action: or redirect: mechanisms. These mechanisms are intended to attach navigational information to buttons within forms through prefixed information; however, due to this vulnerability, insecure target expressions could be executed on the targeted system.
An unauthenticated, remote attacker could exploit the vulnerability by providing malicious expressions through HTTP requests. Processing such expressions could allow the attacker to execute simple expressions or arbitrary commands evaluated as OGNL expressions against the value stack on the targeted system.
Administrators are advised to apply the appropriate updates.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators are advised to monitor affected systems.
Apache has released updated software at the following links:
Cisco customers with active contracts can obtain updates through the Software Center. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via email at firstname.lastname@example.org.
Version 3, October 23, 2013, 12:11 PM: Cisco has released a security advisory to address vulnerabilities in Cisco products using Apache Struts 2.
Version 2 July 25, 2013, 3:48 PM: IntelliShield has updated this alert to reflect a modification in the urgency and exploitability of the Apache Struts action: parameter processing command injection vulnerability.
Version 1, July 18, 2013, 3:03 PM: Apache Struts contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code on the targeted system. Updates are available.
The urgency and severity ratings of this alert are not tailored to individual users; users may value alerts differently based upon their network configurations and circumstances. THE ALERT, AND INFORMATION CONTAINED THEREIN, ARE PROVIDED ON AN "AS IS" BASIS AND DO NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE ALERT, AND INFORMATION CONTAINED THEREIN, OR MATERIALS LINKED FROM THE ALERT, IS AT YOUR OWN RISK. INFORMATION IN THIS ALERT AND ANY RELATED COMMUNICATIONS IS BASED ON OUR KNOWLEDGE AT THE TIME OF PUBLICATION AND IS SUBJECT TO CHANGE WITHOUT NOTICE. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE ALERTS AT ANY TIME.