CVE-2018-17646 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 fillColor 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-6483.
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Analysis
by VulDB Data Team • 05/05/2020
CVE-2018-17646 represents a critical remote code execution vulnerability affecting Foxit Reader version 9.2.0.9297, classified under CWE-476 as "NULL Pointer Dereference" within the context of PDF document processing. This vulnerability stems from insufficient input validation during the parsing of TimeField objects, specifically when handling the fillColor property. The flaw occurs when the application attempts to access object properties without first verifying whether the object reference is valid or has been properly initialized. This type of vulnerability falls under the ATT&CK technique T1059.007 for "Command and Scripting Interpreter: JavaScript', as it enables arbitrary code execution through maliciously crafted PDF content that triggers JavaScript execution within the reader's context. The vulnerability requires user interaction to be exploited, meaning an attacker must convince a target to visit a malicious webpage hosting a crafted PDF file or open a malicious document directly. When a user interacts with such content, the application's PDF parser encounters the malformed TimeField structure and attempts to process the fillColor property without proper null checks. This creates an exploitable condition where the attacker can inject and execute malicious code within the Foxit Reader process, potentially gaining full control over the victim's system. The vulnerability's impact is significant as it allows for privilege escalation and persistence mechanisms, since the code executes with the same privileges as the Foxit Reader application. The flaw demonstrates poor defensive programming practices and highlights the importance of implementing robust input validation and object existence checks in document parsing libraries. Organizations using Foxit Reader should immediately apply the vendor-provided patches and consider implementing network-based protections such as web application firewalls and content filtering to prevent access to malicious PDF content. Additionally, security awareness training for users should emphasize the dangers of opening untrusted PDF files and visiting suspicious websites. The vulnerability also underscores the necessity of sandboxing PDF rendering components and implementing strict input sanitization to prevent similar issues in other PDF processing applications. This flaw represents a classic example of how seemingly minor input validation gaps can lead to severe remote code execution capabilities, making it a critical concern for enterprise security teams managing document processing environments.