CVE-2023-32993

Vulnerability

Overview

CVE-2023-32993 affects the Jenkins SAML Single Sign On (SSO) Plugin, versions 2.0.2 and earlier. The plugin fails to perform hostname validation when connecting to miniOrange or the configured Identity Provider (IdP) to retrieve SAML metadata. This omission means the plugin does not verify that the server it connects to is the legitimate destination, creating a security gap in the authentication flow [1][2].

Exploitation

Prerequisites

An attacker with a position on the network between the Jenkins server and the IdP (or miniOrange service) can exploit this vulnerability by conducting a man-in-the-middle (MITM) attack. The lack of hostname validation allows the attacker to impersonate the metadata endpoint, intercept the connection, and potentially modify or capture SAML metadata without detection [1]. No authentication to Jenkins is required for this network-level attack, but the attacker must be able to intercept traffic—typically requiring access to the same network segment or control over a DNS/network intermediary.

Impact

Assessment

Successful exploitation enables the attacker to intercept and potentially alter SAML metadata responses. This could lead to the disclosure of sensitive configuration details, or more critically, allow the attacker to inject malicious metadata that redirects authentication or obtains session credentials, ultimately compromising the integrity of the single sign-on environment [1][2]. The vulnerability is rated with a CVSS v3.1 base score of 5.9 (Medium) due to the requirement of network access and the potential for significant authentication bypass.

Mitigation

As of the Jenkins Security Advisory 2023-05-16, users should upgrade the SAML SSO Plugin to version 2.0.3 or later, which addresses the hostname validation issue [1]. No workaround is available; upgrading is the sole remediation. Administrators should also ensure network segments are properly isolated to reduce MITM risks.