Description

Spring Security does not consider URL path parameters when processing security constraints. By adding a URL path parameter with special encodings, 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 (see below). 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. In this particular attack, different character encodings used in path parameters allows secured Spring MVC static resource URLs to be bypassed.

Affected Spring Products and Versions

Spring Security
- 4.1.0 - 4.1.4
- 4.2.0 - 4.2.3
- 5.0.0
Spring Framework
- 5.0.0 - 5.0.2
- 4.3.0 - 4.3.13
Older unmaintained versions of Spring Security & Spring Framework were not analyzed and may be impacted

Mitigation

Users of affected versions should apply the following mitigation:

Spring Security
- 5.0.x users should update to 5.0.1
- 4.2.x users should update to 4.2.4
- 4.1.x users should update to 4.1.5
Spring Framework
- 5.0.x users should update to 5.0.3
- 4.3.x users should update to 4.3.14

As a general precaution, users are encouraged to separate public and private resources. For example, separating static resources and mapping them to /resources/public/** and /resources/private/** is preferred to having one common root with mixed public and private resource content underneath.

Credit

The issue was identified by Macchinetta Framework Development Team from NTT Comware, NTT DATA Corporation, and NTT, and responsibly reported to Pivotal.