CVE-2016-4062 in Foxit
Summary
by MITRE
Foxit Reader and PhantomPDF before 7.3.4 on Windows improperly report format errors recursively, which allows remote attackers to cause a denial of service (application hang) via a crafted PDF.
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Analysis
by VulDB Data Team • 10/21/2018
The vulnerability identified as CVE-2016-4062 affects Foxit Reader and PhantomPDF versions prior to 7.3.4 on Windows operating systems. This issue represents a critical flaw in how these PDF rendering applications handle malformed PDF files, specifically concerning their error reporting mechanisms. The vulnerability stems from improper recursive handling of format errors during PDF parsing operations, creating a condition where maliciously crafted PDF documents can trigger excessive resource consumption and application instability.
The technical implementation of this vulnerability involves the recursive error reporting mechanism within the PDF parsing engine of these applications. When encountering malformed PDF structures, the software attempts to recursively process format errors in a manner that does not properly terminate or limit the recursion depth. This recursive behavior causes the application to enter an infinite loop or consume excessive computational resources, ultimately leading to application hang or complete denial of service. The flaw is particularly dangerous because it can be triggered remotely through web browsers or email attachments containing malicious PDF files, making it a significant vector for targeted attacks.
From an operational perspective, this vulnerability creates substantial risk for organizations relying on these PDF readers for document processing and viewing. The denial of service condition affects not only individual user productivity but can also impact broader business operations when multiple users are affected simultaneously. Attackers can exploit this vulnerability through various delivery mechanisms including phishing emails, compromised websites, or malicious file sharing platforms. The remote exploitation capability means that organizations cannot simply isolate the vulnerability through network segmentation, as the attack vector can originate from external sources. This vulnerability directly impacts the availability of critical business applications and can potentially be used as part of larger attack campaigns targeting specific organizations or industries.
The remediation strategy for this vulnerability requires immediate deployment of patches provided by Foxit Corporation, specifically upgrading to version 7.3.4 or later. Organizations should implement comprehensive patch management procedures to ensure all affected systems receive updates promptly. Network administrators should consider implementing PDF filtering solutions at network boundaries to prevent potentially malicious PDF files from reaching end-user systems. Additionally, user education programs should emphasize the importance of avoiding suspicious email attachments and untrusted websites. From a cybersecurity maturity perspective, this vulnerability highlights the importance of proper input validation and error handling in document processing applications, aligning with CWE-707 and ATT&CK techniques related to denial of service and privilege escalation. Organizations should also consider implementing application sandboxing or virtualization for PDF processing to limit the potential impact of similar vulnerabilities in the future.