CVE-2017-1000504 in Jenkins
Summary
by MITRE
A race condition during Jenkins 2.94 and earlier; 2.89.1 and earlier startup could result in the wrong order of execution of commands during initialization. There is a very short window of time after startup during which Jenkins may no longer show the 'Please wait while Jenkins is getting ready to work' message
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Analysis
by VulDB Data Team • 12/27/2019
This vulnerability represents a critical race condition in Jenkins prior to versions 2.94 and 2.89.1, where the initialization sequence fails to maintain proper execution order during system startup. The flaw occurs during the critical early phases of Jenkins bootstrapping when multiple threads or processes attempt to execute initialization commands simultaneously, leading to unpredictable execution order that can compromise system stability and security posture. The race condition manifests as a brief window where the system may prematurely transition away from the initialization phase without properly completing all required setup procedures.
The technical nature of this vulnerability aligns with CWE-362, which describes race conditions where multiple threads or processes access shared resources concurrently without proper synchronization mechanisms. During the startup sequence, Jenkins attempts to initialize various components including plugins, security configurations, and system services, but the lack of proper locking mechanisms or sequential execution guarantees allows for interleaved execution of critical initialization commands. This timing issue creates an opportunity for inconsistent system states where dependent services may attempt to operate before their prerequisites have been properly established, potentially leading to service failures or security misconfigurations.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the integrity of the Jenkins environment. When the system prematurely displays the "Please wait while Jenkins is getting ready to work" message, it indicates that the initialization process has not completed correctly, which could result in incomplete plugin loading, improper security context establishment, or misconfigured system parameters. Attackers could potentially exploit this timing window to inject malicious code or manipulate the initialization sequence before the system reaches a stable state, as the window of opportunity for exploitation is directly related to the duration of the race condition.
Security implications of this vulnerability are significant as they could enable attackers to manipulate Jenkins during its vulnerable startup phase, potentially leading to privilege escalation or unauthorized access to the build environment. The timing window, though brief, provides sufficient opportunity for malicious actors to interfere with the initialization process before proper system hardening measures are fully implemented. Organizations should implement immediate mitigations including upgrading to patched versions of Jenkins, ensuring proper system hardening during startup procedures, and monitoring for unusual initialization patterns or unauthorized access attempts during system boot processes. The vulnerability demonstrates the importance of proper synchronization mechanisms in multi-threaded applications and highlights the critical nature of secure bootstrapping processes in enterprise CI/CD environments.