CVE-2017-16814 in MobilePDF App
Summary
by MITRE
A Directory Traversal issue was discovered in the Foxit MobilePDF app before 6.1 for iOS. This occurs by abusing the URL + escape character during a Wi-Fi transfer, which could be exploited by attackers to bypass intended restrictions on local application files.
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Analysis
by VulDB Data Team • 01/08/2020
The vulnerability identified as CVE-2017-16814 represents a critical directory traversal flaw within the Foxit MobilePDF application for iOS devices. This security weakness exists in versions prior to 6.1 and stems from improper handling of URL parameters during wireless file transfers. The vulnerability manifests when the application processes file paths that contain escape sequences, allowing malicious actors to manipulate the intended file access restrictions. The flaw specifically impacts the application's ability to properly validate and sanitize input parameters that control file system access operations.
The technical implementation of this vulnerability falls under the category of CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. When the Foxit MobilePDF app receives a URL containing escape characters during a Wi-Fi transfer operation, it fails to adequately validate the constructed file path before attempting to access local application files. This improper input validation creates an opportunity for attackers to navigate beyond the intended application boundaries and potentially access restricted system resources or files that should remain protected. The vulnerability exploits the application's insufficient sanitization of user-supplied input during file system operations.
The operational impact of this directory traversal vulnerability extends beyond simple unauthorized file access, as it could potentially enable attackers to read sensitive application data, modify configuration files, or even execute arbitrary code within the application's sandboxed environment. Mobile applications that process user-provided URLs or file paths without proper validation create a significant attack surface where adversaries can exploit these weaknesses to gain unauthorized access to local resources. The vulnerability is particularly concerning in mobile environments where applications often have access to user data, device storage, and potentially sensitive corporate information. Attackers could leverage this weakness to bypass application security controls and access files that should be restricted to authorized users only.
Mitigation strategies for this vulnerability require immediate application updates to version 6.1 or later, which includes proper input validation and sanitization of URL parameters during file transfer operations. Security professionals should implement additional network-level controls to monitor and restrict file transfer protocols that may introduce similar vulnerabilities. Organizations should also conduct thorough security assessments of mobile applications to identify potential path traversal vulnerabilities in other components. The remediation process involves implementing proper parameter validation, using secure coding practices for file system operations, and ensuring that all user-supplied input is properly sanitized before being processed by the application. This vulnerability demonstrates the importance of adhering to secure coding standards and maintaining regular security updates for mobile applications, as highlighted in the ATT&CK framework's application security considerations.