CVE-2016-9879 in Spring Security
Summary
by MITRE
An issue was discovered in Pivotal Spring Security before 3.2.10, 4.1.x before 4.1.4, and 4.2.x before 4.2.1. Spring Security does not consider URL path parameters when processing security constraints. By adding a URL path parameter with an encoded "/" to a request, an attacker may be able to bypass a security constraint. The root cause of this issue is a lack of clarity regarding the handling of path parameters in the Servlet Specification. Some Servlet containers include path parameters in the value returned for getPathInfo() and some do not. Spring Security uses the value returned by getPathInfo() as part of the process of mapping requests to security constraints. The unexpected presence of path parameters can cause a constraint to be bypassed. Users of Apache Tomcat (all current versions) are not affected by this vulnerability since Tomcat follows the guidance previously provided by the Servlet Expert group and strips path parameters from the value returned by getContextPath(), getServletPath(), and getPathInfo(). Users of other Servlet containers based on Apache Tomcat may or may not be affected depending on whether or not the handling of path parameters has been modified. Users of IBM WebSphere Application Server 8.5.x are known to be affected. Users of other containers that implement the Servlet specification may be affected.
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Analysis
by VulDB Data Team • 04/20/2025
This vulnerability in Pivotal Spring Security represents a critical authorization bypass flaw that stems from improper handling of URL path parameters within the security constraint mapping process. The issue affects multiple versions of the Spring Security framework including 3.2.10, 4.1.4, and 4.2.1, where the security system fails to properly account for path parameters that may be present in HTTP requests. The vulnerability exploits a fundamental ambiguity in the Servlet specification regarding how path parameters should be handled, creating a scenario where attackers can manipulate request URLs to circumvent security controls. When path parameters are included in a URL with encoded forward slashes, the Spring Security framework incorrectly processes these parameters during security constraint evaluation, leading to potential unauthorized access to protected resources.
The technical root cause of this vulnerability lies in Spring Security's reliance on the getPathInfo() method from the servlet container to determine request paths for security mapping purposes. According to the servlet specification, the handling of path parameters varies significantly across different servlet containers, with some containers including path parameters in the getPathInfo() return value while others exclude them. This inconsistency creates a security gap when Spring Security assumes uniform behavior across all containers, resulting in security constraints being evaluated against incorrect path information. The vulnerability specifically manifests when attackers append URL path parameters with encoded slashes to requests, effectively bypassing the intended security controls that should restrict access to sensitive resources.
The operational impact of this vulnerability extends beyond simple access control bypasses, potentially enabling attackers to gain unauthorized access to restricted application functionalities, sensitive data, and administrative interfaces. This flaw directly violates the principle of least privilege and can lead to complete system compromise when combined with other vulnerabilities or when targeting critical application components. The vulnerability affects organizations using various servlet containers, with Apache Tomcat users being protected due to its adherence to servlet specification guidance that strips path parameters from path-related methods. However, other containers including IBM WebSphere Application Server 8.5.x are vulnerable, creating widespread exposure across different deployment environments. The issue demonstrates how seemingly minor specification ambiguities can create significant security implications in enterprise security frameworks.
Organizations should implement immediate mitigations including upgrading to patched versions of Spring Security where available, or implementing custom request filtering logic that explicitly handles path parameters before security constraint evaluation. The mitigation strategy should include comprehensive testing of security configurations across different servlet containers to ensure proper path parameter handling. Security teams should also consider implementing additional monitoring and logging mechanisms to detect unusual request patterns that might indicate exploitation attempts. This vulnerability aligns with CWE-284, which addresses improper access control, and maps to ATT&CK technique T1078 for valid accounts and T1566 for phishing, as attackers may leverage this bypass to escalate privileges and gain deeper system access. Organizations should also review their deployment configurations to ensure they are using servlet containers that properly handle path parameters according to specification guidelines, particularly avoiding containers that do not strip path parameters from path-related methods.