CVE-2018-9962 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.0.1.1049. 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 parsing of Annotation's author attribute. 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-5435.
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Analysis
by VulDB Data Team • 02/06/2020
The vulnerability identified as CVE-2018-9962 represents a critical remote code execution flaw in Foxit Reader version 9.0.1.1049 that demonstrates a classic object validation error pattern. This issue resides within the PDF annotation processing functionality where the software fails to properly validate object existence before performing operations on potentially invalid references. The vulnerability operates under the CWE-476 principle of null pointer dereference, where the application assumes object validity without proper verification. Attackers can exploit this weakness by crafting malicious PDF documents containing specially formatted annotation data that triggers the flawed parsing logic. The exploitation requires user interaction through visiting a malicious webpage or opening a compromised PDF file, making it a typical client-side attack vector that aligns with ATT&CK technique T1203 for legitimate user execution.
The technical implementation of this vulnerability stems from improper input validation within the annotation author attribute parsing mechanism. When Foxit Reader processes a PDF document containing an annotation with a malformed author attribute, the software attempts to access object properties without first confirming that the referenced object exists in memory. This pattern of insufficient object validation creates a window of opportunity for attackers to manipulate the application's execution flow through carefully constructed malicious input. The lack of proper bounds checking and object existence verification allows an attacker to potentially overwrite memory locations or redirect execution flow, ultimately enabling arbitrary code execution under the privileges of the currently running Foxit Reader process. This vulnerability directly relates to CWE-843 which specifically addresses access of a resource using an invalid reference.
The operational impact of CVE-2018-9962 extends beyond simple remote code execution to represent a significant threat to enterprise security environments where PDF processing is common. Organizations using Foxit Reader for document review, contract signing, or general office productivity face potential compromise when users encounter malicious PDF content through email attachments, web downloads, or document sharing platforms. The vulnerability's requirement for user interaction makes it particularly dangerous in social engineering campaigns where attackers can craft convincing phishing pages or malicious documents that appear legitimate. Successful exploitation allows attackers to execute code with the same privileges as the Foxit Reader application, potentially leading to full system compromise if the application runs with elevated permissions or if the user has administrative access. This vulnerability also demonstrates the broader challenge of PDF processing security where complex document parsers create numerous potential attack surfaces that require thorough input validation and memory safety checks.
Mitigation strategies for CVE-2018-9962 should focus on both immediate remediation and long-term security hardening approaches. The primary recommendation involves updating to the patched version of Foxit Reader that resolves the annotation parsing vulnerability, which represents the most direct and effective solution. Organizations should also implement network-level controls such as PDF content filtering and web application firewalls that can detect and block malicious PDF content before it reaches end users. Additional defensive measures include restricting user privileges when opening PDF documents, implementing sandboxing mechanisms for PDF processing, and conducting regular security awareness training to reduce successful social engineering attacks. The vulnerability serves as a reminder of the importance of input validation and object safety checks in document processing applications, aligning with security best practices that emphasize defense in depth and proper error handling in software development. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates across all vulnerable systems.