CVE-2020-2300 in Active Directory Plugin
Summary
by MITRE • 11/04/2020
Jenkins Active Directory Plugin 2.19 and earlier does not prohibit the use of an empty password in Windows/ADSI mode, which allows attackers to log in to Jenkins as any user depending on the configuration of the Active Directory server.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 12/02/2020
The vulnerability identified as CVE-2020-2300 affects the Jenkins Active Directory Plugin version 2.19 and earlier, presenting a critical security flaw that undermines authentication mechanisms within Windows/ADSI mode environments. This issue stems from the plugin's failure to properly validate authentication credentials, specifically allowing empty password submissions to proceed without restriction. The flaw exists within the authentication processing logic where the system does not enforce mandatory password validation, creating a pathway for unauthorized access through credential manipulation.
From a technical perspective, the vulnerability manifests as a failure in input validation and authentication control mechanisms. The Active Directory Plugin operates by establishing connections to Windows domain controllers through ADSI (Active Directory Services Interface) protocols, where it typically validates user credentials against domain policies. However, the plugin's implementation does not adequately check for empty password values during the authentication handshake process, allowing attackers to submit blank password fields while providing valid usernames. This behavior aligns with CWE-312, which addresses the exposure of sensitive data through improper handling of credentials, and CWE-287, which covers improper authentication scenarios.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to potentially escalate privileges and gain persistent access to Jenkins environments. When an attacker successfully exploits this vulnerability, they can authenticate as any user within the Active Directory domain, depending on the server's configuration and user permissions. This capability allows for comprehensive system compromise, as Jenkins administrators may have elevated privileges within the CI/CD pipeline, potentially enabling code injection, build manipulation, or access to sensitive deployment credentials. The vulnerability particularly affects organizations that rely on Active Directory integration for Jenkins authentication, making it a significant concern for enterprise environments where Jenkins serves as a critical build and deployment platform.
The security implications of CVE-2020-2300 align with tactics and techniques documented in the MITRE ATT&CK framework, specifically relating to credential access and privilege escalation. Attackers can leverage this vulnerability to perform pass-the-hash or credential theft operations, potentially bypassing other security controls such as multi-factor authentication or network segmentation measures. The vulnerability also demonstrates weaknesses in the principle of least privilege, as the plugin's design does not enforce proper credential validation. Organizations should implement immediate mitigations including plugin version updates to 2.20 or later, which address the empty password validation issue, along with enhanced monitoring of authentication attempts and review of Active Directory user permissions to minimize potential impact.
The remediation approach requires organizations to prioritize the immediate upgrade of the Jenkins Active Directory Plugin to version 2.20 or higher, which includes proper validation of password fields and prevents empty password submissions. Additionally, security administrators should conduct comprehensive vulnerability assessments to identify systems running affected plugin versions and implement network-level controls to monitor for suspicious authentication patterns. Configuration reviews should ensure that Jenkins users have appropriate access controls and that the principle of least privilege is maintained across all Jenkins environments. The vulnerability highlights the importance of proper credential handling and authentication validation in enterprise security architectures, particularly when integrating with critical identity management systems such as Active Directory. Organizations should also consider implementing additional authentication layers, such as LDAP bind validation or custom authentication filters, to provide defense-in-depth against similar credential-based vulnerabilities.