CVE-2019-16552 in Gerrit Trigger Plugin
Summary
by MITRE
A missing permission check in Jenkins Gerrit Trigger Plugin 2.30.1 and earlier allows attackers with Overall/Read permission to connect to an attacker-specified HTTP URL or SSH server using attacker-specified credentials, or determine the existence of a file with a given path on the Jenkins master.
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Analysis
by VulDB Data Team • 12/18/2019
The vulnerability identified as CVE-2019-16552 represents a critical permission bypass flaw within the Jenkins Gerrit Trigger Plugin version 2.30.1 and earlier. This issue stems from insufficient access control mechanisms that fail to properly validate user permissions before executing sensitive operations. The flaw specifically affects systems where the Gerrit Trigger plugin is installed and configured, creating a pathway for unauthorized access to network resources and system information that should be restricted to authorized personnel only.
The technical implementation of this vulnerability manifests through a missing permission check that occurs during the plugin's handling of remote connections and file existence checks. Attackers with merely Overall/Read permission can exploit this weakness to establish connections to arbitrary HTTP endpoints or SSH servers using credentials they specify, effectively bypassing the intended security boundaries. Additionally, the vulnerability allows for file path enumeration on the Jenkins master server, enabling attackers to determine whether specific files or directories exist within the system's filesystem. This dual nature of the vulnerability creates both remote access capabilities and information disclosure risks that significantly compromise system integrity and confidentiality.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it enables attackers to perform reconnaissance activities and potentially establish persistent access to the Jenkins environment. The ability to connect to attacker-specified HTTP URLs or SSH servers means that compromised Jenkins instances could serve as pivoting points for further attacks within the network infrastructure. File existence checking capabilities provide attackers with valuable information about the system's structure, potentially revealing sensitive paths, configuration files, or system artifacts that could aid in subsequent exploitation attempts. This vulnerability particularly affects organizations that rely on Jenkins for continuous integration and deployment processes, as it undermines the security of their automated build environments.
Security professionals should address this vulnerability through immediate patching of the Gerrit Trigger Plugin to version 2.31.0 or later, which contains the necessary permission validation fixes. Organizations should also implement network segmentation and firewall rules to restrict access to Jenkins servers from untrusted networks, limiting the potential attack surface. The vulnerability aligns with CWE-284, which describes improper access control, and maps to ATT&CK technique T1078 for valid accounts and T1046 for network service scanning. Additional mitigations include implementing strict access controls for Jenkins administration interfaces, regularly auditing plugin installations, and monitoring for unusual network connections or file access patterns that might indicate exploitation attempts. Organizations should also consider implementing network intrusion detection systems to monitor for connections to known malicious domains or IP addresses that attackers might attempt to reach through this vulnerability.