CVE-2020-2284 in Liquibase Runner Plugin
Summary
by MITRE
Jenkins Liquibase Runner Plugin 1.4.5 and earlier does not configure its XML parser to prevent XML external entity (XXE) attacks.
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Analysis
by VulDB Data Team • 09/23/2020
The Jenkins Liquibase Runner Plugin vulnerability CVE-2020-2284 represents a critical security flaw in the XML processing configuration of the plugin version 1.4.5 and earlier. This vulnerability falls under the CWE-611 weakness category, specifically addressing insecure XML external entity processing that allows attackers to exploit the system through maliciously crafted XML input. The plugin's failure to properly configure its XML parser creates an avenue for XML external entity attacks that can lead to various security consequences including information disclosure, denial of service, and potentially remote code execution depending on the target environment. The vulnerability exists within the plugin's handling of XML data structures that are commonly used in Liquibase database change management operations.
The technical flaw manifests when the plugin processes XML content without disabling external entity resolution and DTD (Document Type Definition) parsing capabilities. This misconfiguration allows an attacker to craft specially formatted XML input that references external resources or includes malicious entities that can be resolved by the XML parser. When the plugin processes such input, the XML parser automatically resolves these external references, potentially leading to data exfiltration from internal systems, server-side request forgery attacks, or other malicious activities that leverage the parser's capabilities to access local files or network resources. The vulnerability is particularly dangerous because it operates at the XML parsing layer where legitimate plugin functionality intersects with potentially malicious input processing.
The operational impact of this vulnerability extends beyond simple information disclosure and can result in significant security breaches within Jenkins environments. Attackers can leverage XXE vulnerabilities to access internal network resources that would normally be protected by firewalls and network segmentation, as the XML parser operates within the context of the Jenkins server. This creates potential for privilege escalation attacks where attackers can gain unauthorized access to sensitive data or system resources. The vulnerability affects organizations that rely on Jenkins for continuous integration and deployment processes, particularly those using Liquibase for database schema management where the plugin processes XML-based database change scripts. The attack surface is broad since the vulnerability can be exploited through any interface where XML input is processed, including build configurations, database change scripts, or plugin configuration files that utilize XML format.
Mitigation strategies for this vulnerability require immediate action to upgrade to plugin versions that properly configure XML parsers to disable external entity resolution and DTD processing. Organizations should implement the latest available versions of the Jenkins Liquibase Runner Plugin that have addressed this XXE vulnerability through proper XML parser configuration. System administrators must also consider implementing network-level controls such as firewall rules that restrict access to Jenkins servers and limit outbound connections that could be exploited for XXE attacks. The remediation process should include thorough testing of upgraded plugin versions to ensure that legitimate functionality remains intact while the security vulnerability is eliminated. Additionally, organizations should conduct comprehensive vulnerability assessments of their Jenkins environments to identify other potentially affected plugins and systems that may be susceptible to similar XML parsing vulnerabilities. Security teams should monitor for exploitation attempts and implement intrusion detection systems that can identify suspicious XML processing activities that may indicate attempted XXE attacks. This vulnerability highlights the importance of proper XML parser configuration as outlined in security best practices and represents a common weakness that affects numerous applications processing external XML input.