CVE-2019-1003002 in Pipeline Declarative Plugin
Summary
by MITRE
A sandbox bypass vulnerability exists in Pipeline: Declarative Plugin 1.3.3 and earlier in pipeline-model-definition/src/main/groovy/org/jenkinsci/plugins/pipeline/modeldefinition/parser/Converter.groovy that allows attackers with Overall/Read permission to provide a pipeline script to an HTTP endpoint that can result in arbitrary code execution on the Jenkins master JVM.
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Analysis
by VulDB Data Team • 11/26/2024
This vulnerability resides within the Pipeline: Declarative Plugin for Jenkins, specifically in the Converter.groovy file where the sandbox mechanism fails to properly validate user-provided pipeline scripts. The flaw allows attackers with minimal permissions - specifically Overall/Read access - to craft malicious pipeline definitions that bypass the intended security boundaries of the Jenkins sandbox. The vulnerability stems from insufficient input sanitization and validation during the parsing of declarative pipeline syntax, creating a path for arbitrary code execution on the Jenkins master JVM. This represents a critical sandbox escape condition that undermines the fundamental security model of Jenkins pipeline execution.
The technical implementation of this vulnerability exploits the Groovy scripting environment within Jenkins by allowing crafted pipeline definitions to execute potentially dangerous operations through the pipeline parser. Attackers can leverage this by submitting malicious pipeline scripts through HTTP endpoints that are processed by the vulnerable Converter.groovy component. The vulnerability specifically affects versions 1.3.3 and earlier of the pipeline-model-definition plugin, where the sandbox validation logic contains a flaw that permits certain Groovy operations to bypass restrictions. This occurs because the parser fails to adequately sanitize or restrict access to potentially dangerous methods and classes within the Groovy runtime environment that should be blocked in a sandboxed context.
The operational impact of this vulnerability is severe as it allows attackers with read permissions to escalate their privileges and achieve full code execution on the Jenkins master server. This means that an attacker who can read pipeline configurations can potentially execute arbitrary commands with the privileges of the Jenkins master process, which typically runs with elevated system permissions. The consequences extend beyond simple code execution to include potential data exfiltration, system compromise, and further lateral movement within the network environment where Jenkins is deployed. This vulnerability particularly affects continuous integration environments where Jenkins masters often have access to sensitive build artifacts, source code repositories, and deployment systems.
Mitigation strategies for this vulnerability include immediate upgrading to Pipeline: Declarative Plugin version 1.3.4 or later, which contains the necessary fixes to properly enforce sandbox restrictions. Organizations should also implement additional security controls such as restricting access to pipeline editing capabilities, implementing proper network segmentation, and monitoring for unusual pipeline script submissions. The vulnerability aligns with CWE-74 and CWE-798 categories related to improper input validation and hard-coded credentials, and maps to ATT&CK techniques including T1059 for command and scripting interpreter and T1078 for valid accounts. Security teams should also consider implementing pipeline script validation policies and regular security assessments of Jenkins configurations to prevent similar sandbox bypass vulnerabilities from being exploited in other components of the Jenkins ecosystem.