Critical Apache Struts 2 Vulnerability: Protecting Your Data from XXE Attacks

A severe security vulnerability has emerged in Apache Struts 2, placing countless applications at risk of data breaches and server compromises. This critical XML External Entity (XXE) injection flaw, identified as CVE-2025-68493, demands immediate attention from developers and system administrators. Failing to address this vulnerability could lead to attackers stealing sensitive data, executing remote code, and gaining unauthorized access to your systems.

Understanding the Apache Struts 2 XXE Vulnerability

The core of this vulnerability lies within the Apache Struts 2 framework’s handling of XML data. An XXE injection occurs when an application processes XML input that contains references to external entities. Attackers can craft malicious XML payloads to exploit this, forcing the application to access local files, external URLs, or even execute commands on the server. For affected Apache Struts 2 versions, this means a well-crafted XML request can trick the application into revealing sensitive information from the server’s file system, such as configuration files, user credentials, or other proprietary data.

Beyond data exfiltration, a successful XXE attack can also lead to denial-of-service (DoS) attacks, where an attacker can force the server to parse a large amount of data or attempt to access non-existent resources, thereby consuming server resources and making the application unavailable. In some cases, XXE can be leveraged for server-side request forgery (SSRF) attacks, allowing attackers to make requests from the vulnerable server to other internal systems, potentially bypassing network firewalls and access controls.

Impact and Scope of CVE-2025-68493

The far-reaching impact of CVE-2025-68493 cannot be overstated. Apache Struts 2 is a widely adopted open-source web application framework used by a vast number of enterprises globally. This means millions of applications, across various industries, could be susceptible. Organizations processing sensitive customer data, financial information, or critical infrastructure controls via Struts 2 applications are particularly at risk. A successful exploitation could result in:

• Sensitive Data Theft: Attackers can read arbitrary files on the server, including database credentials, private keys, and application source code.
• Server Compromise: In some configurations, XXE can lead to remote code execution, giving attackers full control over the compromised server.
• Denial of Service: Malicious XML payloads can exhaust server resources, leading to application downtime.
• Internal Network Access: Attackers can scan internal networks and interact with services that are otherwise inaccessible from the internet.

Remediation Actions for Apache Struts 2 Users

Addressing this critical vulnerability requires prompt and decisive action. Here’s what developers and system administrators need to do:

• Upgrade Apache Struts 2: The most crucial step is to upgrade your Apache Struts 2 framework to a patched version immediately. Consult the official Apache Struts website for the latest secure releases.
• Disable DTD Processing: As a mitigation strategy, disable DTD (Document Type Definition) processing in your XML parsers. This prevents the parsing of external entities, which is the root cause of XXE vulnerabilities.
• Implement Input Validation: Always validate and sanitize all XML input received by your application. Reject any input that appears suspicious or deviates from expected formats.
• Least Privilege Principle: Ensure that the user account running the Apache Struts 2 application has only the minimum necessary permissions on the server. This limits the damage an attacker can inflict if a compromise occurs.
• Regular Security Audits: Conduct frequent security audits and vulnerability scans of your applications and infrastructure to identify and address weaknesses proactively.
• Monitor Logs: Implement robust logging and monitoring to detect unusual activity that could indicate an attempted or successful XXE attack. Look for access attempts to unusual files or external connections initiated by your application.

Tools for Detection and Mitigation

Leveraging the right tools can significantly aid in identifying and mitigating XXE vulnerabilities in your applications.

Tool Name	Purpose	Link
OWASP ZAP	Automated security scanner for finding web application vulnerabilities, including XXE.	https://www.zaproxy.org/
Burp Suite	Comprehensive platform for web penetration testing, useful for manual XXE testing and exploitation.	https://portswigger.net/burp
Static Application Security Testing (SAST) Tools	Tools like SonarQube or Checkmarx can analyze source code to identify potential XXE vulnerabilities before deployment.	(Refer to vendor websites for specific links)
Dynamic Application Security Testing (DAST) Tools	Tools like Acunetix or Qualys Web Application Scanning can scan running applications for XXE and other vulnerabilities.	(Refer to vendor websites for specific links)

Protecting Your Infrastructure

The discovery of CVE-2025-68493 underscores the persistent threat of web application vulnerabilities. For organizations relying on Apache Struts 2, understanding the mechanics of XXE attacks and implementing the recommended remediation steps is paramount. Proactive security measures, continuous monitoring, and a commitment to keeping software up-to-date are essential for safeguarding sensitive data and maintaining the integrity of your systems.