CVE-2019-0207 in Tapestry
Summary
by MITRE
Tapestry processes assets `/assets/ctx` using classes chain `StaticFilesFilter -> AssetDispatcher -> ContextResource`, which doesn't filter the character `\`, so attacker can perform a path traversal attack to read any files on Windows platform.
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Analysis
by VulDB Data Team • 08/27/2020
The vulnerability identified as CVE-2019-0207 resides within the Apache Tapestry web application framework, specifically within its asset processing pipeline that handles requests to the `/assets/ctx` endpoint. This flaw exists in the class chain StaticFilesFilter -> AssetDispatcher -> ContextResource, where the framework fails to properly sanitize input paths before processing them. The absence of proper filtering for the backslash character `\` creates a critical path traversal vulnerability that can be exploited by malicious actors to access arbitrary files on the underlying Windows system. The vulnerability is particularly concerning because it leverages the Windows-specific path traversal behavior where the backslash serves as a directory separator, making the attack surface more extensive than typical Unix-like systems where forward slashes are used.
The technical implementation of this vulnerability stems from inadequate input validation within the asset processing pipeline. When a request is made to the `/assets/ctx` endpoint, the StaticFilesFilter receives the request and passes it through the AssetDispatcher, which in turn uses ContextResource to resolve the file path. The flaw occurs at the ContextResource level where the backslash character is not properly filtered or sanitized, allowing attackers to inject directory traversal sequences such as `..\` or `\\` into the requested asset paths. This enables an attacker to navigate outside the intended asset directory and access files that should remain protected, including system configuration files, application credentials, or other sensitive data stored on the Windows server.
The operational impact of CVE-2019-0207 is significant for organizations running Apache Tapestry applications on Windows platforms, as it provides attackers with the ability to perform unauthorized file access and potentially escalate their privileges. The vulnerability can be exploited to read sensitive files such as database connection strings, application configuration files, or even system-level files that could contain authentication credentials or other confidential information. This represents a direct violation of the principle of least privilege and could lead to complete system compromise if attackers can access files containing administrative credentials or sensitive application data. The attack requires minimal privileges and can be executed through standard web requests, making it particularly dangerous in environments where Tapestry applications are deployed without proper network segmentation or additional security controls.
Organizations should implement immediate mitigations to address this vulnerability by applying the latest security patches from Apache Tapestry or by implementing custom input validation that filters out backslash characters and other potentially dangerous path traversal sequences. Network segmentation and web application firewalls can provide additional layers of protection by blocking suspicious requests to the `/assets/ctx` endpoint. The vulnerability aligns with CWE-22 Path Traversal and maps to ATT&CK technique T1083 File and Directory Discovery, as attackers can use this vulnerability to enumerate and access files on the compromised system. Regular security audits of web application frameworks and input validation mechanisms should be conducted to prevent similar issues, and organizations should ensure that all web applications are regularly updated with security patches to address known vulnerabilities in their dependencies.
This vulnerability demonstrates the critical importance of proper input validation in web applications, particularly when dealing with file system operations. The flaw highlights the need for comprehensive security testing that includes path traversal scenarios and emphasizes that even seemingly minor implementation oversights can lead to severe security consequences. The vulnerability also underscores the importance of platform-specific considerations in security design, as the behavior of path traversal attacks can vary significantly between operating systems, with Windows presenting unique challenges due to its backslash-based path separator. Organizations should implement automated security scanning tools that can detect such vulnerabilities in their codebases and establish security awareness training for developers to prevent similar issues in future implementations.