CVE-2018-12536 Explained : Impact and Mitigation

Eclipse Jetty Server versions 9.x are affected by a vulnerability that can expose sensitive server paths when handling certain queries. Learn about the impact, technical details, and mitigation steps.

Understanding CVE-2018-12536

Eclipse Jetty Server versions 9.x are susceptible to information exposure through an error message, potentially revealing server paths to unauthorized users.

What is CVE-2018-12536?

When using Eclipse Jetty Server versions 9.x for deploying webapps with default Error Handling, a problematic query that does not correspond to a dynamic url-pattern can lead to a java.nio.file.InvalidPathException. This exception occurs when the DefaultServlet's static file serving handles the query, exposing the complete path to the base resource directory being used by the DefaultServlet and/or the webapp. If the default Error Handler handles this InvalidPathException, the error response will contain the InvalidPathException message, thereby revealing the entire server path to the requesting system.

The Impact of CVE-2018-12536

The vulnerability in Eclipse Jetty Server versions 9.x can result in the exposure of sensitive server paths, potentially aiding attackers in further exploiting the system.

Technical Details of CVE-2018-12536

Eclipse Jetty Server versions 9.x are affected by a vulnerability that can lead to information exposure through error messages.

Vulnerability Description

The issue arises when an intentionally bad query triggers a java.nio.file.InvalidPathException, revealing the full path to the base resource directory used by the DefaultServlet and/or webapp. If the InvalidPathException is handled by the default Error Handler, the error response discloses the server path to the requesting system.

Affected Systems and Versions

Product: Eclipse Jetty
Vendor: The Eclipse Foundation
Versions Affected:
<= 9.2.0

= 9.3.0, < 9.3.24

= 9.4.0, < 9.4.11

Exploitation Mechanism

The vulnerability is exploited by sending a malicious query that does not match a dynamic url-pattern, triggering the InvalidPathException and subsequently exposing the server path.

Mitigation and Prevention

To address CVE-2018-12536, immediate steps and long-term security practices are essential.

Immediate Steps to Take

Update Eclipse Jetty Server to a non-vulnerable version.
Implement proper input validation to prevent malicious queries.
Disable default Error Handling if not required.

Long-Term Security Practices

Regularly monitor and audit server logs for unusual activities.
Educate developers on secure coding practices to prevent similar vulnerabilities.

Patching and Updates

Apply security patches provided by Eclipse Foundation to fix the vulnerability and enhance server security.