CVE-2016-6802 in Shiro
Summary
by MITRE
Apache Shiro before 1.3.2 allows attackers to bypass intended servlet filters and gain access by leveraging use of a non-root servlet context path.
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Analysis
by VulDB Data Team • 09/24/2024
Apache Shiro vulnerability CVE-2016-6802 represents a critical access control flaw that undermines the security of web applications relying on the Apache Shiro authentication framework. This vulnerability specifically affects versions prior to 1.3.2 and stems from improper handling of servlet context paths during filter processing. The flaw occurs when applications deploy Shiro within a non-root servlet context path, creating a condition where malicious actors can bypass intended security filters and gain unauthorized access to protected resources.
The technical root cause of this vulnerability lies in how Shiro processes and validates request paths when operating under non-root context paths. When an application is deployed with a context path other than the root directory, Shiro's filter chain evaluation mechanism fails to properly account for the additional path components. This creates a path traversal condition where attackers can manipulate request URLs to bypass authentication and authorization checks that should normally be enforced by Shiro's security filters. The vulnerability is classified under CWE-285: Improper Authorization, which specifically addresses situations where systems fail to properly enforce access controls.
The operational impact of CVE-2016-6802 extends beyond simple unauthorized access, as it can enable attackers to escalate privileges and perform actions that should be restricted to authenticated users. In web applications where Shiro handles session management and access control, this vulnerability essentially provides a backdoor that allows malicious users to circumvent all security measures implemented through the framework. The attack vector is particularly concerning because it requires no special privileges or advanced techniques beyond understanding basic web application path structures. This vulnerability directly maps to ATT&CK technique T1078.004: Valid Accounts, as it allows attackers to gain access to resources using legitimate authentication mechanisms but bypassing the intended authorization controls.
Organizations using affected versions of Apache Shiro should immediately implement mitigations including upgrading to version 1.3.2 or later, which contains the necessary patches to properly handle non-root context paths. Additional defensive measures include implementing proper input validation for all web requests, configuring web application firewalls to monitor for suspicious path manipulation patterns, and conducting thorough security reviews of all servlet mappings and context configurations. Security teams should also consider implementing runtime monitoring solutions that can detect anomalous access patterns that might indicate exploitation attempts. The vulnerability highlights the importance of thorough security testing during application deployment, particularly when dealing with non-standard context paths that may not be adequately covered by default security configurations.