CVE-2023-41945 in Assembla Auth Plugin
Summary
by MITRE • 09/06/2023
Jenkins Assembla Auth Plugin 1.14 and earlier does not verify that the permissions it grants are enabled, resulting in users with EDIT permissions to be granted Overall/Manage and Overall/SystemRead permissions, even if those permissions are disabled and should not be granted.
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Analysis
by VulDB Data Team • 10/02/2023
The vulnerability identified as CVE-2023-41945 affects the Jenkins Assembla Auth Plugin version 1.14 and earlier, representing a critical authorization flaw that undermines the security model of Jenkins authentication systems. This issue stems from improper permission validation within the plugin's implementation, where the system fails to verify whether specific permissions are actually enabled before granting them to authenticated users. The flaw specifically targets the relationship between user roles and permission assignments, creating a scenario where users with EDIT permissions inadvertently receive elevated privileges that should remain restricted.
The technical root cause of this vulnerability lies in the plugin's failure to perform proper access control validation during the authentication and authorization process. When users authenticate through the Assembla authentication mechanism, the plugin processes their permissions without cross-referencing the actual permission settings configured within the Jenkins system. This oversight allows for privilege escalation where users who should only possess basic editing capabilities gain access to critical system management functions including Overall/Manage and Overall/SystemRead permissions. The vulnerability operates at the intersection of authentication and authorization controls, fundamentally compromising the principle of least privilege that is essential for secure system administration.
The operational impact of this vulnerability is significant as it enables unauthorized users to gain administrative access to Jenkins instances that rely on the Assembla authentication plugin. Attackers who can authenticate through Assembla can exploit this flaw to elevate their privileges and potentially compromise the entire Jenkins environment. The granted Overall/Manage permissions allow users to modify system configurations, manage plugins, create and modify jobs, and control access controls, while Overall/SystemRead permissions provide visibility into system-level information that could be used for further exploitation. This vulnerability directly violates the security principle that access rights should be strictly controlled and validated against the system's permission settings rather than being automatically granted based on authentication alone.
From a cybersecurity perspective, this vulnerability aligns with CWE-284, which addresses improper access control, and represents a clear example of how authentication systems can be undermined by insufficient authorization validation. The flaw also relates to ATT&CK technique T1078.004, which covers valid accounts and credential access, as it allows unauthorized privilege escalation through legitimate authentication mechanisms. Organizations using Jenkins with the affected plugin version face heightened risk of unauthorized access to their continuous integration and deployment pipelines, potentially leading to code injection, build system compromise, and unauthorized modification of critical infrastructure components.
The recommended mitigation strategy involves immediate upgrading of the Jenkins Assembla Auth Plugin to version 1.15 or later, which contains the necessary fixes to properly validate permission settings before granting access. System administrators should also conduct thorough audits of their Jenkins permission configurations to identify and revoke any unauthorized elevated permissions that may have been granted due to this vulnerability. Additionally, implementing multi-factor authentication and regular permission reviews can help reduce the attack surface and provide defense-in-depth measures against similar authorization flaws. Organizations should also consider monitoring authentication logs for suspicious permission elevation activities that could indicate exploitation attempts of this vulnerability.