CVE-2017-16586 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 8.3.2.25013. 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 addAnnot method. 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-5295.
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Analysis
by VulDB Data Team • 12/16/2019
CVE-2017-16586 represents a critical remote code execution vulnerability affecting Foxit Reader version 8.3.2.25013 and potentially other versions within the same release cycle. This vulnerability resides within the addAnnot method of the PDF processing engine, where insufficient input validation creates a dangerous condition that allows attackers to manipulate object references without proper existence verification. The flaw specifically manifests when the application attempts to perform operations on objects that have not been properly validated, creating a classic use-after-free or null pointer dereference scenario that can be exploited through malicious PDF content. The vulnerability requires user interaction to be successfully exploited, meaning that targets must either visit a malicious webpage hosting the exploit or open a specially crafted malicious PDF file, which aligns with common attack vectors used in social engineering campaigns targeting office productivity software.
The technical implementation of this vulnerability stems from a fundamental failure in object lifecycle management within the PDF rendering engine. When processing PDF annotations, the addAnnot method fails to validate whether referenced objects actually exist within the document context before attempting to manipulate them. This validation gap creates an opportunity for attackers to craft malicious PDF files containing crafted object references that, when processed by the vulnerable Foxit Reader, trigger unintended code execution. The vulnerability operates at the application layer and can be classified under CWE-476 as Null Pointer Dereference, though it more specifically represents a failure in proper object validation that enables arbitrary code execution. The security implications extend beyond simple code execution as the exploit operates within the context of the current process, meaning that successful exploitation could lead to complete system compromise depending on the privileges of the user running the vulnerable software.
The operational impact of CVE-2017-16586 extends significantly beyond the immediate exploitation vector, as Foxit Reader represents a widely deployed PDF viewer in enterprise environments where users frequently encounter PDF documents from various sources. This vulnerability creates a substantial risk for organizations since PDF files are commonly shared through email attachments, web downloads, and document management systems, making the attack surface extremely broad. Attackers can leverage this vulnerability through various delivery mechanisms including phishing campaigns, malicious websites, or compromised document repositories, with the added benefit that exploitation does not require sophisticated technical skills beyond crafting appropriate PDF content. The vulnerability's classification under ATT&CK technique T1203 (Exploitation for Client Execution) highlights its potential for establishing persistent access within target environments, particularly when combined with other attack techniques such as initial access through malicious email or web-based delivery.
Organizations affected by CVE-2017-16586 should implement immediate mitigations including updating to the latest available version of Foxit Reader where the vulnerability has been patched, as well as implementing network-based controls such as PDF file filtering and sandboxing solutions to prevent exploitation attempts. Security teams should also conduct comprehensive vulnerability assessments to identify all systems running vulnerable versions of the software and ensure that appropriate network segmentation is in place to limit potential lateral movement if exploitation occurs. Additionally, user education programs should emphasize the importance of only opening PDF files from trusted sources and maintaining awareness of social engineering tactics that might be used to deliver malicious content through PDF documents. The vulnerability demonstrates the critical importance of input validation and proper object management in security-critical applications, particularly those handling untrusted data formats such as PDF files, and serves as a reminder of the ongoing need for robust security practices in document processing software that handles complex file formats with extensive object-oriented structures.