Apache Struts 2 REST Plugin RCE via Deserialization
Actively exploited in the wild. Patch or mitigate immediately — don't wait for a maintenance window.
An unauthenticated attacker, remotely over the network, with no user interaction, can fully compromise the system — steal data, tamper with it and take it offline.
The REST Plugin in Apache Struts 2.1.1 through 2.3.x before 2.3.34 and 2.5.x before 2.5.13 uses an XStreamHandler with an instance of XStream for deserialization without any type filtering, which can lead to Remote Code Execution when deserializing XML payloads.
Techniques marked “observed” are corroborated by threat intelligence; the rest are inferred from the weakness type (CWE) and attack vector.
Corroborated threat activity referencing this CVE — with source and confidence, not inference.
These techniques were analysed against this CVE's real-world exploitation — the matching entries in the ATT&CK chain above are marked “observed”.
Generated by Wavense from the CVE record — an immediate mitigation and the permanent fix.
As an interim measure, disable or restrict access to the Struts REST plugin functionality if it's not essential for operations. Implement a Web Application Firewall (WAF) to inspect and block suspicious XML content or known deserialization exploit patterns targeting Struts REST endpoints. Enhance monitoring for unusual process execution or network activity on servers running Apache Struts 2.
The permanent fix is to upgrade Apache Struts 2 to a patched version immediately. Specifically, upgrade to Apache Struts 2.3.34 or 2.5.13, or any later release. These versions implement critical type filtering during XStream deserialization to prevent malicious object instantiation, thereby resolving the RCE vulnerability.
An attacker can achieve Remote Code Execution (RCE) by sending specially crafted XML payloads to vulnerable Struts REST endpoints. This allows for arbitrary code execution on the server, potentially leading to full system compromise, data exfiltration, or further network pivot attacks. The business consequences include severe data breaches, service disruption, and significant reputational damage.
Other CVEs affecting struts
Forced OGNL evaluation, when evaluated on raw user input in tag attributes, may lead to remote code execution. Affected software : Apache Struts 2.0.0 - Struts 2.5.25.
The Struts 1 plugin in Apache Struts 2.1.x and 2.3.x might allow remote code execution via a malicious field value passed in a raw message to the ActionMessage.
The Jakarta Multipart parser in Apache Struts 2 2.3.x before 2.3.32 and 2.5.x before 2.5.10.1 has incorrect exception handling and error-message generation during file-upload attempts, which allows remote attackers to execute arbitrary commands via a crafted Content-Type, Content-Disposition, or Content-Length HTTP header, as exploited in the wild in March 2017 with a Content-Type header containing a #cmd= string.
Unspecified vulnerability in Oracle Java SE 6u113, 7u99, and 8u77; Java SE Embedded 8u77; and JRockit R28.3.9 allows remote attackers to affect confidentiality, integrity, and availability via vectors related to JMX.
Apache Struts 2.0.0 through 2.3.15 allows remote attackers to execute arbitrary OGNL expressions via a parameter with a crafted (1) action:, (2) redirect:, or (3) redirectAction: prefix.
The ExceptionDelegator component in Apache Struts before 2.2.3.1 interprets parameter values as OGNL expressions during certain exception handling for mismatched data types of properties, which allows remote attackers to execute arbitrary Java code via a crafted parameter.
JBoss Seam 2 (jboss-seam2), as used in JBoss Enterprise Application Platform 4.3.0 for Red Hat Linux, does not properly sanitize inputs for JBoss Expression Language (EL) expressions, which allows remote attackers to execute arbitrary code via a crafted URL. NOTE: this is only a vulnerability when the Java Security Manager is not properly configured.
Apache Struts versions 2.3 to 2.3.34 and 2.5 to 2.5.16 suffer from possible Remote Code Execution when alwaysSelectFullNamespace is true (either by user or a plugin like Convention Plugin) and then: results are used with no namespace and in same time, its upper package have no or wildcard namespace and similar to results, same possibility when using url tag which doesn't have value and action set and in same time, its upper package have no or wildcard namespace.