Overview
On December 8, 2020, Struts released a security bulletin disclosing a potential remote code execution vulnerability (CVE-2020-17530) in S2-061.
The vulnerability stems from insufficient input validation. This results in two forced Object Graph Navigation Library (OGNL) evaluations when the original user input is calculated.
When the OGNL expression is forced in Struts tag attributes and can be modified by external input, an attacker could craft a malicious OGNL expression to trigger the vulnerability.
The vulnerability has been fixed in Struts 2.5.26. Affected users are advised to upgrade to Struts 2.5.26 without delay.
For more information, see Struts’s security bulletin at the following link:
Affected Versions
- Struts 2.0.0 – Struts 2.5.25
Unaffected Versions
- Struts version >= Struts 2.5.26
Solution
Struts has officially released a new version to fix the preceding vulnerability. Users are advised to upgrade as soon as possible.
If users cannot upgrade for the time being, they should avoid using forced OGNL evaluation on untrusted user input to reduce risks.
The official security bulletin is available at the following link:
Statement
This advisory is only used to describe a potential risk. NSFOCUS does not provide any commitment or promise on this advisory. NSFOCUS and the author will not bear any liability for any direct and/or indirect consequences and losses caused by transmitting and/or using this advisory. NSFOCUS reserves all the rights to modify and interpret this advisory. Please include this statement paragraph when reproducing or transferring this advisory. Do not modify this advisory, add/delete any information to/from it, or use this advisory for commercial purposes without permission from NSFOCUS.
About NSFOCUS
NSFOCUS, Inc., a global network and cyber security leader, protects enterprises and carriers from advanced cyber attacks. The company’s Intelligent Hybrid Security strategy utilizes both cloud and on-premises security platforms, built on a foundation of real-time global threat intelligence, to provide multi-layered, unified and dynamic protection against advanced cyber attacks.
NSFOCUS works with Fortune Global 500 companies, including four of the world’s five largest financial institutions, organizations in insurance, retail, healthcare, critical infrastructure industries as well as government agencies. NSFOCUS has technology and channel partners in more than 60 countries, is a member of both the Microsoft Active Protections Program (MAPP), and the Cloud Security Alliance (CSA).
A wholly owned subsidiary of NSFOCUS Technologies Group Co., Ltd., the company has operations in the Americas, Europe, the Middle East and Asia Pacific.
