#VU45703 Code Injection in Apache Struts - CVE-2019-0230
Published: August 14, 2020 / Updated: June 17, 2021
Apache Struts
Apache Foundation
Description
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The Apache Struts frameworks, when forced, performs double evaluation
of attributes' values assigned to certain tags attributes such as id
so it is possible to pass in a value that will be evaluated again when a
tag's attributes will be rendered. With a carefully crafted request,
this can lead to Remote Code Execution (RCE).
The problem only applies when forcing OGNL evaluation inside a Struts tag attribute, when the expression to evaluate references raw, unvalidated input that an attacker is able to directly modify by crafting a corresponding request.
Example:
<s:url var="url" namespace="/employee" action="list"/><s:a id="%{skillName}" href="%{url}">List available Employees</s:a>
If an attacker is able to modify the skillName attribute in a request such that a raw OGNL expression gets passed to the skillName property without further validation, the provided OGNL expression contained in the skillName attribute gets evaluated when the tag is rendered as a result of the request.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.