CVE-2020-1957

Vulnerability

Overview

CVE-2020-1957 is an authentication bypass vulnerability in Apache Shiro versions prior to 1.5.2. The root cause lies in how Shiro's URL path matching interacts with Spring dynamic controllers. When a specially crafted request is sent, Shiro may fail to apply authentication filters, allowing the request to reach a protected resource without proper credentials [1].

Exploitation

An attacker can exploit this vulnerability by sending a crafted HTTP request to a target application that uses Apache Shiro with Spring dynamic controllers. The attack does not require prior authentication and can be performed remotely. The crafted request exploits a discrepancy between Shiro's path matching logic and Spring's controller mapping, causing Shiro to incorrectly treat the request as unauthenticated [1].

Impact

Successful exploitation allows an unauthenticated attacker to bypass authentication and access protected resources. This could lead to unauthorized data access, privilege escalation, or further compromise of the application and its underlying systems [1].

Mitigation

The vulnerability is fixed in Apache Shiro version 1.5.2. Users are strongly advised to upgrade to this version or later. No workarounds are documented. The Apache Shiro project provides the fix in the official repository [1][2].