CVE-2018-9975 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.0.1.1049. 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 shift events. 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 under the context of the current process. Was ZDI-CAN-5762.
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Analysis
by VulDB Data Team • 08/15/2024
The vulnerability identified as CVE-2018-9975 represents a critical remote code execution flaw affecting Foxit Reader version 9.0.1.1049 and potentially other versions within the same release cycle. This security weakness stems from improper input validation mechanisms within the application's event handling system, specifically when processing shift events that occur during document interaction. The vulnerability operates under the Common Weakness Enumeration classification of CWE-476 which describes NULL pointer dereferences, indicating that the application fails to properly validate object existence before executing operations on referenced elements. The attack vector requires user interaction through either visiting a malicious webpage or opening a specially crafted malicious file, making this a typical client-side exploitation scenario that aligns with ATT&CK technique T1203 for Exploitation for Client Execution.
The technical implementation of this vulnerability occurs within the PDF rendering engine of Foxit Reader where shift events are processed without adequate validation of object references. When a malicious PDF document is opened or viewed, the application attempts to handle shift key events without first confirming that the target object exists in memory, leading to a potential null pointer dereference condition. This flaw allows an attacker to manipulate the application's memory state and execute arbitrary code within the context of the currently running process, effectively providing a complete system compromise if the application runs with elevated privileges. The vulnerability's exploitation requires careful crafting of PDF content that triggers the specific shift event handling code path, making it a targeted attack rather than a broad-based exploit.
The operational impact of CVE-2018-9975 extends beyond simple remote code execution to encompass complete system compromise capabilities for attackers who successfully target vulnerable installations. Since Foxit Reader is commonly used for viewing and editing PDF documents across various organizational environments, this vulnerability creates a significant attack surface that could be exploited in phishing campaigns or drive-by download scenarios. The fact that exploitation requires user interaction provides some defense-in-depth but does not eliminate the risk entirely, as social engineering tactics can effectively convince users to interact with malicious content. Organizations using Foxit Reader versions prior to the patched release face potential data breaches, privilege escalation attacks, and persistent backdoor installations that could remain undetected for extended periods.
Mitigation strategies for CVE-2018-9975 should include immediate patch deployment from Foxit Corporation, as the vendor released security updates addressing this specific vulnerability. Organizations should also implement network-based security controls such as web application firewalls and content filtering systems to block access to known malicious PDF content. Additionally, user education and awareness programs should emphasize the importance of avoiding suspicious PDF files and websites, particularly those that prompt immediate downloads or require user interaction to view content. Security teams should monitor for exploitation attempts through network traffic analysis and endpoint detection systems that can identify anomalous behavior patterns associated with code execution attempts. The vulnerability's classification under CWE-476 and its exploitation pattern align with standard security hardening practices that emphasize input validation and proper error handling in application code, making this a prime example of why robust software security practices are essential for preventing remote code execution vulnerabilities.