CVE-2020-13933

Vulnerability

Overview

CVE-2020-13933 is an authentication bypass vulnerability in Apache Shiro, a Java security framework. The flaw exists in versions prior to 1.6.0 and allows an attacker to bypass authentication mechanisms by sending a specially crafted HTTP request. The root cause lies in how Shiro processes certain request parameters, which can be manipulated to circumvent the authentication checks [1].

Exploitation

Conditions

Exploitation requires network access to an application using Apache Shiro for authentication. No prior authentication is needed; the attacker sends a malicious HTTP request that triggers the bypass. The exact request structure is not publicly detailed, but the vulnerability is triggered by crafting specific input that Shiro fails to validate correctly [1].

Impact

Successful exploitation allows an attacker to bypass authentication entirely, gaining unauthorized access to protected resources or functionality. This could lead to privilege escalation, data exposure, or further compromise of the application [1].

Mitigation

The vulnerability is fixed in Apache Shiro version 1.6.0. Users should upgrade to this version or later. No workarounds are documented. The issue is not listed in CISA's Known Exploited Vulnerabilities catalog as of the publication date [1][2].