CVE-2020-13814 in Foxit
Summary
by MITRE
An issue was discovered in Foxit Reader and PhantomPDF before 9.7.1. It has a use-after-free via a document that lacks a dictionary.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 10/22/2020
The vulnerability identified as CVE-2020-13814 represents a critical use-after-free flaw affecting Foxit Reader and PhantomPDF software versions prior to 9.7.1. This issue stems from improper memory management handling when processing PDF documents that lack essential dictionary structures. The flaw occurs during the parsing and rendering of malformed PDF files where the application fails to properly validate document integrity before attempting memory operations. Such vulnerabilities typically arise when software does not adequately check for required data structures or when it continues processing after encountering unexpected document formats without proper error handling mechanisms.
The technical implementation of this vulnerability involves a classic use-after-free condition where memory allocated for dictionary objects is freed but subsequent code references this memory location before proper validation. This occurs specifically when the PDF parser encounters documents missing dictionary entries and attempts to access freed memory locations during rendering or parsing operations. The absence of proper bounds checking and memory lifecycle management creates opportunities for attackers to craft malicious PDF documents that trigger this condition. When the application attempts to access freed memory, it may result in arbitrary code execution, memory corruption, or application crashes that could be exploited for privilege escalation or denial of service attacks.
The operational impact of CVE-2020-13814 extends beyond simple application instability to potentially enable sophisticated attack vectors that align with ATT&CK technique T1203 for Exploitation for Execution and T1059 for Command and Scripting Interpreter. The vulnerability affects users of Foxit Reader and PhantomPDF across multiple operating systems including windows and linux platforms, making it particularly dangerous in enterprise environments where these applications are commonly deployed. Organizations using these PDF viewers for document review, legal proceedings, or business communications face significant risk exposure when vulnerable versions remain in use. The attack surface is broad since PDF documents are frequently shared through email, web portals, and document management systems, creating multiple potential entry points for exploitation.
Security mitigations for this vulnerability require immediate patching of all affected Foxit Reader and PhantomPDF installations to version 9.7.1 or later. System administrators should implement network-based controls such as PDF document filtering at network perimeters to prevent potentially malicious documents from reaching end-user systems. Additionally, users should be trained to avoid opening PDF files from untrusted sources and to maintain current software versions through automated update mechanisms. The vulnerability demonstrates the importance of proper input validation and memory management practices that align with CWE-416 for Use After Free and CWE-119 for Improper Access Control. Organizations should also consider implementing sandboxing techniques for PDF processing and monitoring for unusual memory access patterns that could indicate exploitation attempts. Regular security assessments of document processing applications and maintaining up-to-date threat intelligence regarding similar vulnerabilities in PDF libraries will help prevent future incidents.