CVE-2015-5174 in Tomcat
Summary
by MITRE
Directory traversal vulnerability in RequestUtil.java in Apache Tomcat 6.x before 6.0.45, 7.x before 7.0.65, and 8.x before 8.0.27 allows remote authenticated users to bypass intended SecurityManager restrictions and list a parent directory via a /.. (slash dot dot) in a pathname used by a web application in a getResource, getResourceAsStream, or getResourcePaths call, as demonstrated by the $CATALINA_BASE/webapps directory.
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Analysis
by VulDB Data Team • 07/08/2022
The vulnerability described in CVE-2015-5174 represents a critical directory traversal flaw within Apache Tomcat's RequestUtil.java component that affects multiple versions across the 6.x, 7.x, and 8.x release lines. This security weakness specifically targets the SecurityManager restrictions that are designed to prevent unauthorized access to sensitive system resources. The vulnerability manifests when authenticated remote attackers exploit improper input validation in web application resource resolution methods, particularly those involving getResource, getResourceAsStream, and getResourcePaths calls. The flaw enables attackers to bypass intended security boundaries by utilizing the well-known /.. (slash dot dot) sequence in pathnames, which allows them to navigate upward in the directory structure and access parent directories that should normally be restricted. The attack vector is particularly concerning because it operates within the context of legitimate web application resource requests, making it difficult to detect through standard network monitoring.
The technical implementation of this vulnerability stems from insufficient validation of pathname inputs within the RequestUtil.java file, which is a core component responsible for processing HTTP request parameters and resource paths in Apache Tomcat. When web applications make calls to the aforementioned resource resolution methods, the application fails to properly sanitize or validate the input paths, allowing maliciously crafted paths containing directory traversal sequences to pass through undetected. This flaw specifically impacts the $CATALINA_BASE/webapps directory structure, which serves as the primary deployment location for web applications in Tomcat environments. The vulnerability's exploitation demonstrates a clear path to privilege escalation and information disclosure, as attackers can enumerate directory contents and potentially access sensitive files that reside outside the intended web application boundaries. This issue directly corresponds to CWE-22, which defines improper limitation of a pathname to a restricted directory, and aligns with ATT&CK technique T1083 for discovering system information through directory traversal attacks.
The operational impact of CVE-2015-5174 extends far beyond simple information disclosure, as it provides attackers with the capability to map the underlying file system structure and potentially access sensitive configuration files, application source code, or even system-level resources that should remain isolated from web-facing applications. In a production environment, this vulnerability could enable attackers to discover database connection strings, cryptographic keys, or other sensitive information stored in configuration files outside the web application's intended scope. The vulnerability's authentication requirement does not mitigate its severity, as authenticated users often possess sufficient privileges to cause significant damage within the application's context. Organizations running affected versions of Apache Tomcat face the risk of unauthorized access to their entire web application deployment structure, potentially leading to full system compromise if combined with other vulnerabilities or if the application has access to sensitive backend systems. The impact is particularly severe in environments where Tomcat serves as a primary application server for enterprise web applications, as the vulnerability could expose critical business logic and data to unauthorized access.
The recommended mitigation strategy for CVE-2015-5174 involves immediate deployment of patched versions of Apache Tomcat, specifically upgrading to versions 6.0.45, 7.0.65, or 8.0.27 and later, which contain the necessary code modifications to properly validate pathname inputs. Organizations should also implement additional defensive measures including input validation at the application level, implementing proper access controls for web application resources, and monitoring for suspicious directory traversal patterns in application logs. Network segmentation and the principle of least privilege should be enforced to limit the potential impact of successful exploitation attempts. Security teams should conduct comprehensive vulnerability assessments to identify any applications running on affected Tomcat versions and ensure that all instances have been properly updated. The vulnerability highlights the importance of maintaining current security patches and implementing robust input validation practices across all web application components, particularly those handling user-supplied data that may be processed as file paths or resource identifiers. Organizations should also consider implementing web application firewalls or security monitoring tools that can detect and block suspicious directory traversal attempts before they can be exploited against the system.