CVE-2002-0493 in Tomcat
Summary
by MITRE
Apache Tomcat may be started without proper security settings if errors are encountered while reading the web.xml file, which could allow attackers to bypass intended restrictions.
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Analysis
by VulDB Data Team • 10/30/2024
The vulnerability identified as CVE-2002-0493 represents a critical security flaw in Apache Tomcat web server implementations that fundamentally undermines access control mechanisms through improper error handling during configuration file processing. This vulnerability stems from the application's failure to enforce security restrictions when encountering parsing errors in the web.xml deployment descriptor file, creating a dangerous fallback behavior that can be exploited by malicious actors. The issue manifests when Tomcat encounters malformed or inaccessible web.xml files during startup or deployment processes, leading to the server operating with reduced security protections instead of failing securely.
The technical root cause of this vulnerability lies in the improper error recovery mechanisms within Tomcat's configuration parsing logic. When the system encounters errors while reading web.xml files, it fails to maintain the intended security context and instead continues operation with default or less restrictive settings. This behavior creates a security boundary failure where the application's access control policies are bypassed, allowing unauthorized users to potentially access restricted resources or functionality that should be protected by the web.xml configuration. The vulnerability is particularly insidious because it operates silently, without explicit error messages alerting administrators to the compromised security state, making detection and remediation challenging.
From an operational perspective, this vulnerability presents significant risks to organizations relying on Tomcat for web application hosting, as it can enable attackers to bypass authentication mechanisms, access sensitive data, or execute unauthorized operations within the application environment. The impact extends beyond simple information disclosure to potentially allow privilege escalation and full system compromise, especially when combined with other vulnerabilities or when the affected applications handle sensitive user data. Attackers can exploit this weakness by crafting malicious web.xml files or by causing legitimate files to become unreadable, triggering the insecure fallback behavior that disables intended security controls.
Security practitioners should implement comprehensive monitoring and logging of Tomcat startup processes to detect unusual error conditions that might trigger this vulnerability. The recommended mitigations include ensuring proper file permissions and access controls on web.xml files, implementing robust error handling procedures that enforce security boundaries even during configuration parsing failures, and regularly updating Tomcat installations to versions that address this specific vulnerability. Organizations should also establish automated checks to verify that security settings remain intact after configuration changes and implement network segmentation to limit the potential impact of any successful exploitation attempts. This vulnerability aligns with CWE-254 and CWE-693 categories related to security misconfigurations and inadequate error handling, and it maps to ATT&CK techniques involving privilege escalation and defense evasion through configuration manipulation.