CVE-2018-17647 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 boundItem method 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-6484.
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Analysis
by VulDB Data Team • 05/05/2020
CVE-2018-17647 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 TimeField boundItem method. This vulnerability stems from insufficient input validation mechanisms that fail to verify object existence before executing operations on potentially null references. The flaw operates at the intersection of software security principles and improper error handling, creating a pathway for malicious exploitation through crafted PDF content.
The technical implementation of this vulnerability occurs when Foxit Reader processes TimeField objects within PDF documents, specifically during the boundItem method execution. When the software attempts to access a boundItem without first validating its existence, it creates a condition where a null pointer dereference can occur. This fundamental flaw in object validation allows attackers to construct malicious PDF files that, when processed by the vulnerable reader, trigger the execution path leading to arbitrary code execution. The vulnerability demonstrates a classic software security weakness where defensive programming practices are insufficiently implemented.
Operational exploitation of this vulnerability requires user interaction through either visiting a malicious webpage that hosts a crafted PDF or opening a specifically designed malicious file. This requirement places the vulnerability in the category of client-side attacks that rely on social engineering and user behavior modification. The attack vector specifically targets the PDF rendering engine of Foxit Reader, leveraging the application's trust in parsed PDF content to execute malicious payloads. Once executed, the code operates within the context of the current process, potentially allowing full system compromise depending on the privileges of the user running the vulnerable software.
The security implications extend beyond simple code execution to encompass complete system compromise when combined with other exploitation techniques. This vulnerability aligns with ATT&CK technique T1203 as it enables initial access through malicious document delivery, and can support lateral movement when combined with privilege escalation techniques. The lack of proper validation creates a persistent threat vector that can be exploited repeatedly against vulnerable installations, making it particularly dangerous in enterprise environments where PDF processing is common.
Mitigation strategies for CVE-2018-17647 should prioritize immediate software updates from Foxit Corporation to address the underlying object validation flaw. Organizations must implement network-based protections such as PDF content filtering and web application firewalls to prevent delivery of malicious content to vulnerable systems. Additionally, user education regarding suspicious document attachments and website visits should be emphasized to reduce successful exploitation attempts. System administrators should consider implementing application whitelisting policies that restrict execution of untrusted PDF content and monitor for unusual process behavior that may indicate exploitation attempts. The vulnerability underscores the importance of robust input validation and defensive programming practices in preventing remote code execution attacks that can compromise entire systems through seemingly innocuous document processing operations.