CVE-2022-20614 in Mailer Plugin
Summary
by MITRE • 01/12/2022
A missing permission check in Jenkins Mailer Plugin 391.ve4a_38c1b_cf4b_ and earlier allows attackers with Overall/Read access to use the DNS used by the Jenkins instance to resolve an attacker-specified hostname.
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Analysis
by VulDB Data Team • 03/09/2026
The vulnerability identified as CVE-2022-20614 represents a critical permission bypass flaw within the Jenkins Mailer Plugin, specifically affecting versions up to and including 391.ve4a_38c1b_cf4b_. This issue stems from a missing permission check that allows authenticated attackers with minimal Overall/Read access to exploit the DNS resolution capabilities of the Jenkins instance. The flaw resides in the plugin's improper handling of DNS queries, creating an avenue for attackers to leverage the Jenkins server's network connectivity for malicious DNS resolution activities. The vulnerability is particularly concerning because it operates at the network level, potentially enabling attackers to perform DNS tunneling, reconnaissance activities, or redirect traffic through the Jenkins server.
The technical implementation of this vulnerability demonstrates a clear violation of the principle of least privilege and proper access control mechanisms. Attackers with only Overall/Read permissions can manipulate the DNS resolution process to query arbitrary hostnames, effectively using the Jenkins instance as a DNS resolver for their own purposes. This behavior directly relates to CWE-284, which addresses improper access control, and more specifically aligns with CWE-732, which deals with incorrect permissions for critical resources. The flaw essentially allows attackers to perform DNS lookups through the Jenkins server's network interface without proper authorization, potentially exposing internal network structures or enabling further reconnaissance activities.
The operational impact of CVE-2022-20614 extends beyond simple DNS resolution capabilities, as it provides attackers with a potential foothold for more sophisticated attacks. The vulnerability can be exploited to perform DNS-based reconnaissance, potentially mapping internal network structures that would otherwise be hidden from external view. This capability aligns with ATT&CK technique T1016 which involves the discovery of network connections and T1082 which covers system information discovery. Additionally, the vulnerability could enable attackers to perform DNS tunneling, where they might exfiltrate data through DNS queries or use the Jenkins server as a pivot point for accessing other network resources. The attack surface is particularly dangerous because it leverages the Jenkins server's legitimate network connectivity to perform malicious activities without raising obvious alerts.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security posture improvements. The primary recommendation involves upgrading the Jenkins Mailer Plugin to version 392.ve4a_38c1b_cf4b_ or later, which includes the necessary permission checks to prevent unauthorized DNS resolution. Organizations should also implement network segmentation to limit the Jenkins server's ability to perform DNS lookups to only trusted domains. The principle of least privilege should be enforced by restricting Overall/Read permissions to only essential personnel, and monitoring should be implemented to detect unusual DNS resolution patterns that might indicate exploitation attempts. Security teams should also consider implementing network-level controls such as DNS filtering or firewalls to restrict outbound DNS queries from Jenkins servers, thereby limiting the potential impact of such vulnerabilities. The vulnerability highlights the importance of proper input validation and access control implementation in plugin architectures, as well as the necessity of regular security assessments to identify missing permission checks that could be exploited by attackers.