CVE-2018-17642 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 colSpan property of a TimeField. The issue results from the lack of validating 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-6479.
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Analysis
by VulDB Data Team • 05/05/2020
CVE-2018-17642 represents a critical remote code execution vulnerability affecting Foxit Reader version 9.2.0.9297 that demonstrates a classic object-oriented programming flaw with severe operational implications. This vulnerability resides within the TimeField component's colSpan property handling mechanism, where the application fails to validate whether an object reference exists before attempting to perform operations on it. The flaw constitutes a direct violation of secure coding principles and aligns with CWE-476, which specifically addresses null pointer dereference vulnerabilities. The vulnerability requires user interaction to be exploited, making it particularly dangerous in social engineering scenarios where attackers can craft malicious web pages or documents designed to trigger the vulnerable code path when opened by unsuspecting users.
The technical exploitation of this vulnerability occurs through a remote code execution vector that leverages the absence of proper object validation in the PDF parsing engine. When Foxit Reader processes a malicious PDF document containing a specially crafted TimeField element with an invalid colSpan property, the application attempts to access an uninitialized or freed object reference without proper null checks. This creates a condition where memory corruption can occur, potentially allowing attackers to inject and execute arbitrary code within the context of the Foxit Reader process. The vulnerability's impact extends beyond simple code execution as it operates within the same security context as the application itself, potentially enabling privilege escalation and system compromise. This type of vulnerability is particularly concerning given that PDF readers are commonly used for business and government documents, making them prime targets for advanced persistent threats.
From an operational perspective, this vulnerability presents significant risks to organizations relying on Foxit Reader for document processing and viewing. The requirement for user interaction makes it susceptible to phishing campaigns and malicious document distribution attacks, where attackers can entice victims to open seemingly legitimate documents containing the exploit. The vulnerability's presence in a widely deployed PDF reader application means that successful exploitation can lead to widespread compromise across organizations, particularly those with limited security awareness training programs. The attack surface is further expanded due to the nature of PDF documents being commonly shared via email, cloud storage services, and web portals, creating multiple vectors for exploitation. Organizations may face regulatory compliance issues if such vulnerabilities are exploited to gain unauthorized access to sensitive data, as the exploitation could constitute a breach under various data protection frameworks.
Effective mitigation strategies for CVE-2018-17642 should include immediate patch application from Foxit Corporation, as the vendor has released updates addressing this specific vulnerability. Organizations should implement network-based protections such as PDF content filtering and web application firewalls to block malicious PDF documents before they reach end users. User education and awareness programs must be strengthened to help employees recognize potentially malicious documents and avoid opening suspicious attachments or visiting untrusted websites. Additionally, organizations should consider implementing sandboxing techniques for PDF processing and maintaining strict access controls to limit the impact if exploitation occurs. The vulnerability's classification under ATT&CK technique T1203 (Exploitation for Client Execution) highlights the importance of endpoint protection measures and regular security assessments to identify and remediate similar vulnerabilities across the organization's software ecosystem.