EUVD-2025-6498

Comprehensive Technical Analysis of EUVD-2025-6498

1. Vulnerability Assessment and Severity Evaluation

The vulnerability described in EUVD-2025-6498 affects Apache Tomcat and is identified by CVE-2025-24813. This issue involves a path equivalence problem where the 'file.Name' (Internal Dot) can lead to Remote Code Execution (RCE), Information Disclosure, and the injection of malicious content into uploaded files via the write-enabled Default Servlet.

Severity Evaluation:

• CVSS Base Score: 9.8
• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

The high CVSS score indicates a critical vulnerability due to its potential for remote exploitation without user interaction, leading to high impact on confidentiality, integrity, and availability.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

1. Information Disclosure and Content Injection:

   • Conditions:
     • Writes enabled for the default servlet.
     • Support for partial PUT enabled.
     • Target URL for security-sensitive uploads is a sub-directory of a target URL for public uploads.
     • Attacker knowledge of the names of security-sensitive files.
     • Security-sensitive files uploaded via partial PUT.
   • Exploitation: An attacker can view or inject content into security-sensitive files by exploiting the path equivalence issue.

2. Remote Code Execution:

   • Conditions:
     • Writes enabled for the default servlet.
     • Support for partial PUT enabled.
     • Application using Tomcat's file-based session persistence with the default storage location.
     • Application includes a library vulnerable to deserialization attacks.
   • Exploitation: An attacker can execute arbitrary code by leveraging the deserialization vulnerability in conjunction with the path equivalence issue.

Exploitation Methods:

• Path Equivalence: Manipulating file paths to bypass security checks.
• Deserialization Attack: Exploiting vulnerable libraries to execute malicious code.

3. Affected Systems and Software Versions

Affected Versions:

• Apache Tomcat 11.0.0-M1 through 11.0.2
• Apache Tomcat 10.1.0-M1 through 10.1.34
• Apache Tomcat 9.0.0.M1 through 9.0.98

Recommended Upgrades:

• Upgrade to Apache Tomcat 11.0.3, 10.1.35, or 9.0.99 to mitigate the issue.

4. Recommended Mitigation Strategies

1. Immediate Mitigation:

   • Disable writes for the default servlet.
   • Disable support for partial PUT if not required.
   • Ensure that security-sensitive uploads are not sub-directories of public uploads.
   • Use a non-default storage location for file-based session persistence.

2. Long-Term Mitigation:

   • Upgrade to the patched versions of Apache Tomcat (11.0.3, 10.1.35, or 9.0.99).
   • Regularly update and patch all software components.
   • Implement strict input validation and sanitization.
   • Use security tools to monitor and detect suspicious activities.

5. Impact on European Cybersecurity Landscape

The vulnerability poses a significant risk to organizations using Apache Tomcat within the European Union. Given the widespread use of Apache Tomcat in web applications, the potential for large-scale exploitation is high. This could lead to data breaches, unauthorized access, and service disruptions, impacting both public and private sectors.

6. Technical Details for Security Professionals

Technical Analysis:

• Path Equivalence Issue: The vulnerability arises from the way Apache Tomcat handles file paths, allowing an attacker to manipulate the 'file.Name' to access or modify files outside the intended directory.
• Deserialization Vulnerability: The exploitation of deserialization attacks relies on the presence of vulnerable libraries within the application. Attackers can craft malicious payloads that, when deserialized, execute arbitrary code.

Detection and Monitoring:

• Log Analysis: Monitor logs for unusual file access patterns and PUT requests.
• Intrusion Detection Systems (IDS): Deploy IDS to detect and alert on suspicious activities related to file uploads and deserialization attempts.
• Code Review: Conduct thorough code reviews to identify and mitigate deserialization vulnerabilities.

References:

• NVD Entry
• Apache Tomcat GitHub Commits
• Proof of Concept
• Mitigation Strategies

By addressing this vulnerability promptly and comprehensively, organizations can significantly reduce the risk of exploitation and protect their systems and data.