CVE-2020-11989 in Shiro
Summary
by MITRE
Apache Shiro before 1.5.3, when using Apache Shiro with Spring dynamic controllers, a specially crafted request may cause an authentication bypass.
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Analysis
by VulDB Data Team • 06/23/2020
Apache Shiro version 1.5.3 and earlier contains a critical authentication bypass vulnerability that specifically affects applications utilizing Spring dynamic controllers. This vulnerability arises from improper handling of certain request parameters within the authentication flow, allowing malicious actors to bypass authentication mechanisms entirely. The flaw manifests when Shiro processes requests through Spring's dynamic controller framework, creating a path for crafted HTTP requests to manipulate the authentication state without proper credential validation.
The technical root cause stems from how Shiro's authentication filter interacts with Spring's request processing pipeline. When Spring dynamically resolves controller methods based on request parameters, Shiro's security checks fail to properly validate the authenticity of requests that contain specially crafted parameter values. This occurs because the framework does not adequately sanitize or validate incoming parameters before they are processed within the authentication context. The vulnerability specifically exploits the interaction between Shiro's session management and Spring's parameter binding mechanisms, creating a condition where authentication bypass can occur through carefully constructed request payloads.
The operational impact of this vulnerability is significant for organizations running affected Apache Shiro versions in production environments. An attacker could potentially gain unauthorized access to protected resources, bypassing all authentication controls and accessing sensitive data or functionality. This vulnerability affects web applications that rely on Shiro for security and use Spring Framework's dynamic controller capabilities. The attack surface includes any application that implements Shiro authentication alongside Spring's dynamic request handling, making it particularly concerning for enterprise applications and web services.
Security mitigations for this vulnerability require immediate upgrading to Apache Shiro version 1.5.3 or later, which includes patches addressing the authentication bypass condition. Organizations should also implement additional defensive measures such as input validation and parameter sanitization within their application code. Network-level protections including web application firewalls and request filtering can help detect and block malicious payloads attempting to exploit this vulnerability. The vulnerability aligns with CWE-285: Improper Authorization and ATT&CK technique T1078: Valid Accounts, as it allows attackers to bypass authentication controls and gain unauthorized access to protected resources. Regular security assessments and code reviews focusing on authentication flows are recommended to identify similar issues in custom implementations. Organizations should also monitor for related vulnerabilities in their Spring Framework dependencies, as the interaction between these components creates additional attack vectors that require comprehensive security testing.