CVE-2017-14826 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code 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 formNodes method of XFA Node objects. The issue results from the lack of proper validation of user-supplied data, which can result in a type confusion condition. An attacker can leverage this vulnerability to execute code under the context of the current process. Was ZDI-CAN-5018.
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Analysis
by VulDB Data Team • 12/16/2019
CVE-2017-14826 represents a critical type confusion vulnerability affecting Foxit Reader version 8.3.1.21155 that enables remote code execution through crafted XFA form nodes. This vulnerability resides within the formNodes method of XFA Node objects, where insufficient input validation allows attackers to manipulate object type information during runtime operations. The flaw constitutes a direct violation of secure coding principles and falls under the CWE-471 classification for improper handling of type confusion conditions. The vulnerability operates by exploiting the lack of proper bounds checking and type verification when processing user-supplied data within the XFA (XML Forms Architecture) processing engine, creating opportunities for attackers to manipulate memory layout and execute arbitrary code with the privileges of the current user process.
The technical exploitation of this vulnerability requires a user to interact with malicious content through either visiting a specially crafted web page or opening a malicious PDF file containing crafted XFA elements. This attack vector aligns with the ATT&CK technique T1203 for Exploitation for Client Execution, where adversaries leverage vulnerabilities in software applications to execute malicious code on target systems. The type confusion condition occurs when the application fails to properly validate the type of objects being manipulated during XFA node processing, allowing an attacker to inject data that causes the application to interpret memory locations as different object types than intended. This misinterpretation leads to memory corruption and potential code execution.
The operational impact of this vulnerability extends beyond simple remote code execution to include complete system compromise when attackers leverage the elevated privileges of the Foxit Reader process. The vulnerability's remote exploitability means that attackers can target users without requiring physical access or additional attack vectors, making it particularly dangerous in enterprise environments where PDF documents are frequently shared. The security implications include potential data exfiltration, persistence mechanisms through malicious file execution, and lateral movement capabilities when the compromised system serves as a foothold for further attacks. Organizations using Foxit Reader 8.3.1.21155 face significant risk exposure due to the ease of exploitation and the broad attack surface created by PDF document processing capabilities.
Mitigation strategies for CVE-2017-14826 should focus on immediate remediation through official patches provided by Foxit Corporation, while implementing additional defensive measures such as restricting PDF file execution in sensitive environments and deploying web application firewalls to filter malicious content. Network segmentation and user education regarding safe PDF handling practices can help reduce attack surface, though these measures provide only partial protection. Security monitoring should include detection of suspicious XFA processing activities and unusual memory allocation patterns that may indicate exploitation attempts. The vulnerability's classification as a type confusion issue emphasizes the importance of input validation and proper object type handling in software development processes, aligning with industry best practices for preventing similar vulnerabilities in future releases. Organizations should also consider implementing sandboxing mechanisms for PDF processing and maintaining up-to-date threat intelligence to detect potential exploitation attempts targeting this vulnerability.