CVE-2016-3722 in Jenkins
Summary
by MITRE
CloudBees Jenkins before 2.3 and LTS before 1.651.2 allow remote authenticated users with multiple accounts to cause a denial of service (unable to login) by editing the "full name."
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Analysis
by VulDB Data Team • 08/19/2022
This vulnerability exists in CloudBees Jenkins versions prior to 2.3 and LTS versions before 1.651.2, where authenticated users with multiple accounts can exploit a flaw in the user management system to cause a denial of service condition. The specific technical flaw occurs when users attempt to edit their "full name" field in the system, which triggers an improper validation mechanism that affects the authentication process. The vulnerability is classified under CWE-20 as an input validation error, where the system fails to properly sanitize user-provided data during account modification operations. This issue represents a significant security concern as it allows attackers to disrupt legitimate user access to the Jenkins system through a seemingly benign administrative function.
The operational impact of this vulnerability extends beyond simple service disruption, as it creates a persistent denial of service condition that prevents legitimate users from logging into the system. When exploited, the vulnerability causes the Jenkins authentication subsystem to become unstable, rendering the entire system inaccessible to authenticated users until the underlying issue is resolved. This type of attack falls under the ATT&CK technique T1499.004 for Network Denial of Service, where the attacker leverages legitimate system functionality to create an availability compromise. The vulnerability is particularly dangerous in enterprise environments where Jenkins serves as a critical build and deployment platform, as unauthorized users could effectively lock out legitimate administrators and developers.
The root cause of this vulnerability lies in the insufficient validation of user input during the full name modification process within Jenkins user management. When multiple accounts exist with similar characteristics or when the full name field contains certain characters or patterns, the system's internal state becomes corrupted, leading to authentication failures. This flaw demonstrates a lack of proper state management and input sanitization in the user account modification workflow. The vulnerability is exacerbated by the fact that it requires only authenticated access with multiple accounts, making it accessible to users who have already gained some level of system access through other means. Organizations should implement immediate mitigations including upgrading to patched versions of Jenkins, applying the relevant security updates, and implementing additional access controls to limit the ability of users to modify account information in ways that could disrupt system availability.
The broader implications of this vulnerability highlight the importance of proper input validation and state management in enterprise software systems. This issue demonstrates how seemingly minor functionality flaws can create significant security impacts when combined with the right conditions. Organizations should conduct thorough security assessments of their Jenkins installations to identify similar vulnerabilities in user management and authentication subsystems. The vulnerability also underscores the need for proper access controls and the principle of least privilege, where users should not be granted unnecessary permissions that could be exploited to cause system disruptions. System administrators should monitor for unusual account modification patterns and implement logging mechanisms to detect potential exploitation attempts of this and similar vulnerabilities.