CVE-2017-14819 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to disclose sensitive information on vulnerable installations of Foxit Reader 8.3.1.21155. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the channel number member of the cdef box. The issue results from the lack of proper validation of user-supplied data, which can result in a read past the end of an allocated object. An attacker can leverage this in conjunction with other vulnerabilities to execute code in the context of the current process. Was ZDI-CAN-5011.
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Analysis
by VulDB Data Team • 12/16/2019
The vulnerability identified as CVE-2017-14819 represents a critical information disclosure flaw affecting Foxit Reader version 8.3.1.21155 and potentially other versions within the same release cycle. This security issue resides within the PDF parsing functionality of the application, specifically targeting the handling of the channel number member within the cdef box structure. The vulnerability demonstrates characteristics consistent with a buffer over-read condition, where the application fails to properly validate user-supplied data before processing it. The flaw manifests when the PDF parser attempts to read beyond the boundaries of allocated memory structures, potentially exposing sensitive data from adjacent memory locations. This type of vulnerability falls under the CWE-125 category of "Out-of-bounds Read" which is classified as a fundamental memory safety issue that can lead to information disclosure and potentially more severe consequences when combined with other exploit techniques. The attack vector requires user interaction, meaning that an attacker must convince a victim to visit a malicious webpage or open a specially crafted malicious PDF file containing the malformed cdef box structure.
The technical exploitation of this vulnerability occurs through the manipulation of PDF file structures, specifically targeting the cdef box component which is part of the PDF specification for defining color space parameters. When Foxit Reader processes a PDF containing the maliciously crafted channel number member, the application's parser fails to validate the bounds of the data structure, leading to a situation where memory reading operations extend beyond the intended buffer boundaries. This memory corruption can result in the disclosure of sensitive information including but not limited to stack contents, heap data, or other process memory segments that may contain credentials, encryption keys, or other confidential data. The vulnerability's impact is amplified by the fact that it operates within the context of the currently running process, meaning that successful exploitation could potentially provide attackers with access to the same privileges and data access as the legitimate user. This represents a significant concern for enterprise environments where PDF readers are frequently used to process documents from untrusted sources.
The operational impact of CVE-2017-14819 extends beyond simple information disclosure, as it creates a potential pathway for more sophisticated attacks when combined with other vulnerabilities or exploit techniques. The vulnerability's classification aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: JavaScript', as PDF documents often contain JavaScript code that can be executed by vulnerable readers. Additionally, this flaw can be leveraged as part of a broader attack chain where the information disclosure serves as a stepping stone for privilege escalation or lateral movement within a network. Organizations using Foxit Reader in their document processing workflows face significant risk, particularly in environments where users regularly open PDF files from external sources or untrusted websites. The vulnerability's remote exploitability means that attackers can craft malicious PDF files or web pages that automatically trigger the vulnerability without requiring physical access to the target system. This makes the attack surface particularly broad and difficult to control from a network security perspective, as it can be exploited through email attachments, web downloads, or even embedded within other file formats that may be processed by the vulnerable application.
Mitigation strategies for CVE-2017-14819 should focus on both immediate remediation and long-term security posture improvements. The most effective immediate solution involves updating to a patched version of Foxit Reader where the buffer over-read condition has been addressed through proper input validation and bounds checking. Organizations should also implement network-based controls such as PDF file filtering at perimeter defenses, blocking PDF files from untrusted sources, and implementing sandboxing techniques for PDF processing. The vulnerability's characteristics make it particularly susceptible to defense-in-depth strategies including web application firewalls that can detect and block malformed PDF content, endpoint detection and response solutions that monitor for suspicious memory access patterns, and user education programs to reduce the likelihood of successful social engineering attacks that rely on user interaction. Additionally, security teams should consider implementing automated patch management processes to ensure that all vulnerable systems are updated promptly, as this vulnerability could be exploited as part of a broader campaign targeting specific industries or organizations. The remediation process should also include thorough vulnerability scanning and assessment to identify all potentially affected systems within the organization's infrastructure.