CVE-2023-32987 in Reverse Proxy Auth Plugin
Summary
by MITRE • 05/16/2023
A cross-site request forgery (CSRF) vulnerability in Jenkins Reverse Proxy Auth Plugin 1.7.4 and earlier allows attackers to connect to an attacker-specified LDAP server using attacker-specified credentials.
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Analysis
by VulDB Data Team • 04/26/2025
The CVE-2023-32987 vulnerability represents a critical cross-site request forgery flaw within the Jenkins Reverse Proxy Auth Plugin version 1.7.4 and earlier. This vulnerability specifically targets the authentication mechanisms of Jenkins environments that rely on reverse proxy authentication, creating a significant security risk for organizations that depend on this plugin for their identity management infrastructure. The flaw enables malicious actors to manipulate the authentication flow by forcing legitimate users to establish connections to arbitrary LDAP servers using credentials controlled by the attacker, thereby compromising the integrity of the authentication process.
The technical exploitation of this CSRF vulnerability occurs through the manipulation of HTTP requests that are typically initiated by authenticated users. When a user interacts with the Jenkins interface, the malicious actor can craft a specially crafted request that, when executed, causes the application to establish an LDAP connection to a server specified by the attacker rather than the legitimate authentication server. This occurs because the reverse proxy authentication plugin fails to properly validate or sanitize the LDAP server parameters during the authentication process, allowing an attacker to inject malicious parameters that override the intended authentication flow. The vulnerability stems from inadequate input validation and the absence of proper CSRF token verification mechanisms within the plugin's authentication handling code, making it susceptible to unauthorized manipulation of the authentication parameters.
The operational impact of this vulnerability extends beyond simple credential theft, as it allows attackers to potentially bypass authentication entirely or redirect users to malicious authentication endpoints. Organizations utilizing Jenkins with reverse proxy authentication are particularly at risk since the vulnerability enables attackers to inject arbitrary LDAP credentials, potentially enabling them to authenticate as any user within the system or to establish unauthorized access to backend systems that rely on the Jenkins authentication infrastructure. The implications are particularly severe in enterprise environments where Jenkins serves as a central authentication hub for multiple applications and services, as successful exploitation could lead to widespread compromise of the entire infrastructure. This vulnerability aligns with CWE-352, which specifically addresses cross-site request forgery vulnerabilities, and maps to ATT&CK technique T1078.004 which covers valid accounts and T1566.002 which covers spearphishing via social media, as attackers may leverage this vulnerability in conjunction with social engineering campaigns to gain unauthorized access to Jenkins environments.
Mitigation strategies for CVE-2023-32987 should prioritize immediate plugin updates to versions that address the CSRF vulnerability, as the most effective defense against this specific flaw. Organizations must also implement robust network segmentation and access controls to limit the exposure of Jenkins instances to untrusted networks, while ensuring that proper CSRF protection mechanisms are enabled and configured throughout the Jenkins environment. Additional protective measures include implementing strict input validation for all authentication parameters, configuring proper access controls and monitoring for suspicious authentication attempts, and conducting regular security assessments of authentication infrastructure. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and implementing defense-in-depth strategies, particularly for authentication systems that serve as gateways to critical enterprise resources. Organizations should also establish incident response procedures specifically tailored to address authentication-related vulnerabilities and consider implementing additional authentication layers such as multi-factor authentication to reduce the impact of potential exploitation.