CVE-2017-14836 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 8.3.1. 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 modDate attribute of Annotation objects. 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-5028.
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Analysis
by VulDB Data Team • 12/16/2019
CVE-2017-14836 represents a critical remote code execution vulnerability affecting Foxit Reader version 8.3.1 that demonstrates a classic null pointer dereference flaw in the PDF annotation processing subsystem. This vulnerability falls under the CWE-476 category of NULL Pointer Dereference, where the software fails to validate that an object reference is valid before attempting to access its properties or methods. The specific weakness occurs within the modDate attribute handling of Annotation objects, where the application does not properly validate whether the target object exists before performing operations on it. This fundamental validation failure creates an exploitable condition that allows remote attackers to craft malicious PDF files containing specially crafted annotation objects that trigger the vulnerability when processed by the vulnerable software.
The attack vector requires user interaction, specifically targeting the victim to visit a malicious webpage hosting the exploit or open a malicious PDF file containing the crafted annotation data. This user interaction requirement aligns with ATT&CK technique T1203 - Exploitation for Client Execution, where adversaries leverage legitimate software to execute malicious code. The vulnerability operates at the application layer, specifically within the PDF rendering engine of Foxit Reader, where the modDate attribute of annotation objects is processed without proper object validation. When a maliciously crafted PDF is opened or viewed, the application attempts to access the modDate attribute of an annotation object that may not have been properly initialized or allocated, leading to a memory access violation that can be exploited to gain arbitrary code execution privileges.
The operational impact of this vulnerability extends beyond simple code execution, as the attacker can leverage this condition to execute code under the context of the current process, potentially escalating privileges or accessing sensitive system resources. This represents a privilege escalation scenario where the malicious code runs with the same permissions as the Foxit Reader application, which typically runs with the user's privileges. The vulnerability's exploitation potential is heightened by the fact that PDF files are commonly shared via email, web downloads, and file transfers, making this a widespread attack surface. Security researchers have noted that this vulnerability demonstrates poor input validation practices and inadequate error handling in the PDF parsing logic, which are fundamental security principles that should be enforced throughout the application's lifecycle. The ZDI-CAN-5028 reference indicates this was properly identified and tracked by the Zero Day Initiative, highlighting the significance of the vulnerability in the broader cybersecurity landscape.
Mitigation strategies for CVE-2017-14836 should include immediate patching of Foxit Reader to version 8.3.2 or later, which contains the necessary fixes for the annotation object validation issue. Organizations should also implement network-level controls such as PDF file content filtering and sandboxing solutions that can detect and neutralize malicious PDF content before it reaches end users. Additionally, security awareness training should be emphasized to educate users about the risks of opening untrusted PDF files from unknown sources, as the user interaction requirement means social engineering remains a critical attack vector. Network administrators should consider implementing web application firewalls and content inspection tools that can identify and block malicious PDF content based on known exploit patterns. The vulnerability also underscores the importance of proper software development practices including input validation, proper error handling, and defensive programming techniques that prevent null pointer dereference conditions from occurring in production code.