A critical Server-Side Request Forgery (SSRF) vulnerability has been discovered in the Apache CXF Web Application Description Language (WADL) service description for REST web services. This vulnerability, tracked as CVE-2024-29736, affects versions of Apache CXF prior to 4..5, 3.6.4, and 3.5.9.

The affected service allows an attacker to perform SSRF-style attacks on web services that have been misconfigured to permit the use of a custom stylesheet parameter. This blog post will cover the details of the vulnerability, how the attack can be triggered and provide guidance on how to mitigate and protect your server against this issue.

Exploit Details

An SSRF vulnerability occurs when an attacker can make unauthorized requests from a vulnerable server to other internal or external resources, potentially leading to unauthorized access, data exfiltration or significant damage within a target organization.

In this specific scenario, the vulnerability lies within the handling of custom stylesheet parameters in the WADL service description. The attack can be carried out if a malicious user provides a crafted URL or POST request containing a dangerous external resource to fetch, which is then processed by the vulnerable server with the custom stylesheet parameter.

Here's a code snippet illustrating how the vulnerability can be triggered

POST /services?_wadl=&_stylesheet=[malicious_url] HTTP/1.1
Host: vulnerable-server
Content-Length:

In this example, [malicious_url] should be replaced with the address of an attacker-controlled domain or an IP address pointing to an external or internal resource that the attacker wants to access or exfiltrate data from.

Original References

Details about the vulnerability were first published on the Apache Foundation's official website, and they have provided links to relevant resources, such as the advisory notice and the actual patch being applied to the source code, as listed below:

- Apache CXF Security Advisory: https://cxf.apache.org/security-advisories.data/CVE-2024-29736.txt.asc
- Apache Foundation Source Code Patch: https://gitbox.apache.org/repos/asf?p=cxf.git;a=commit;h=b9f7ec1dc07ad925788ce5bf2d5eef971a20538

Mitigation and Protection

To effectively mitigate and protect against this vulnerability, organizations running affected versions of Apache CXF should immediately update their software installations to the latest release, which has been patched to address this issue.

Apache CXF 3.5.9

Alternatively, if upgrading is not currently feasible, administrators can disable the vulnerable feature by ensuring the custom stylesheet parameter is not configured in their systems.

Conclusion

The CVE-2024-29736 SSRF vulnerability in the WADL service description of Apache CXF is a critically severe issue that could enable an attacker to perform unauthorized actions within the target organization or access sensitive data. To safeguard against this vulnerability, it is highly recommended for administrators to update their Apache CXF installations to the newest patched versions or disable the use of custom stylesheet parameters as a temporary mitigation measure.

Remember that staying informed about the latest security vulnerabilities is essential in order to protect your organization's valuable assets and maintain a strong security posture. Stay safe and secure!

Timeline

Published on: 07/19/2024 09:15:04 UTC
Last modified on: 08/22/2024 17:31:48 UTC