CVE-2018-17632 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.2.0.9297. 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 handling of the resolveNode event. The issue results from the lack of validation of the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-6700.
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Analysis
by VulDB Data Team • 05/05/2020
CVE-2018-17632 represents a critical remote code execution vulnerability affecting Foxit Reader version 9.2.0.9297, classified under CWE-476 as a NULL Pointer Dereference vulnerability. This flaw resides in the PDF processing engine's handling of the resolveNode event, where the application fails to validate whether an object exists before attempting to perform operations on it. The vulnerability stems from inadequate input validation mechanisms within the document parsing logic, creating a path where maliciously crafted PDF files can trigger unexpected behavior in the application's memory management subsystem.
The technical exploitation of this vulnerability requires user interaction through either visiting a malicious webpage hosting a crafted PDF or opening a specially constructed file. When the vulnerable Foxit Reader processes such content, the resolveNode event handler attempts to access a pointer that has not been properly validated, leading to a null pointer dereference condition. This memory access violation can be leveraged by attackers to inject and execute arbitrary code within the context of the current process, effectively compromising the victim's system. The vulnerability operates at the application level within the PDF rendering engine, making it particularly dangerous as it can be triggered through standard document viewing operations.
From an operational perspective, this vulnerability presents significant risk to organizations relying on Foxit Reader for document processing, as it enables attackers to gain unauthorized code execution capabilities without requiring elevated privileges. The attack surface is expanded through web-based delivery methods, allowing for phishing campaigns or compromised websites to serve as attack vectors. The vulnerability's classification aligns with ATT&CK technique T1203, which covers Exploitation for Client Execution, as it exploits application vulnerabilities to execute malicious code on target systems. The lack of proper object validation creates a fundamental flaw in the application's defensive mechanisms, allowing attackers to manipulate the execution flow through carefully crafted input data.
Organizations should implement immediate mitigations including updating to patched versions of Foxit Reader, implementing network-based restrictions on PDF file downloads, and deploying application whitelisting controls to prevent unauthorized execution. Security teams should also consider monitoring for unusual PDF processing activities and implementing sandboxing mechanisms for PDF document handling. The vulnerability demonstrates the importance of proper input validation and object existence checking in preventing exploitation of memory corruption vulnerabilities. Additional protective measures include user education about suspicious PDF files, network segmentation to limit access to sensitive systems, and regular security assessments of document processing applications to identify similar validation weaknesses. Organizations should also consider implementing email filtering solutions that can detect and block malicious PDF attachments before they reach end users.