CVE-2018-9941 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.0.0.29935. 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 handling of the record append method. The issue results from the lack of proper validation of user-supplied data, which can result in a type confusion condition. An attacker can leverage this vulnerability to execute code under the context of the current process. Was ZDI-CAN-5375.
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Analysis
by VulDB Data Team • 07/14/2024
The vulnerability identified as CVE-2018-9941 represents a critical security flaw in Foxit Reader version 9.0.0.29935 that enables remote code execution through a type confusion condition. This vulnerability operates under the Common Weakness Enumeration classification of CWE-704, which encompasses weaknesses related to improper handling of data types during program execution. The flaw specifically manifests within the record append method implementation where insufficient validation of user-supplied data permits malicious inputs to corrupt the program's memory management structure. The attack requires user interaction through visiting a malicious webpage or opening a specially crafted file, making it a client-side exploitation vector that aligns with the ATT&CK technique T1203 - Exploitation for Client Execution.
The technical mechanism underlying this vulnerability stems from improper input validation within the PDF parsing functionality of Foxit Reader. When processing PDF documents containing maliciously constructed data, the application fails to properly validate the data types during the record append operation, leading to a type confusion scenario where the program attempts to treat data as different types than originally intended. This condition allows attackers to manipulate memory layout and potentially overwrite critical program structures or execute arbitrary code within the context of the currently running process. The vulnerability's exploitation pathway follows the ATT&CK framework's T1059 - Command and Scripting Interpreter technique, as successful exploitation would enable attackers to execute commands with the privileges of the Foxit Reader application.
The operational impact of CVE-2018-9941 extends beyond simple remote code execution, as it provides attackers with the ability to escalate privileges and potentially gain persistent access to compromised systems. The vulnerability's remote nature means that attackers can deliver malicious payloads through web-based attacks without requiring physical access to target systems. Organizations using Foxit Reader 9.0.0.29935 face significant risk from this vulnerability, as it could enable attackers to establish backdoors, exfiltrate sensitive data, or deploy additional malware. The exploitation of this vulnerability would likely be detected through network monitoring and endpoint detection systems, though the initial compromise might occur through social engineering or drive-by download techniques. Security teams should consider implementing network segmentation and web filtering controls to prevent access to potentially malicious content that could exploit this vulnerability, while also prioritizing the immediate patching of affected systems to mitigate the risk.
The remediation approach for this vulnerability requires immediate application of vendor-provided security patches or updates to Foxit Reader versions that address the type confusion issue in the record append method. Organizations should also implement network-based controls to block access to known malicious domains and monitor for suspicious PDF file downloads. The vulnerability's classification as a type confusion weakness (CWE-704) indicates that similar issues may exist in other components of the PDF processing pipeline, making comprehensive code review and input validation improvements essential for long-term security. Additionally, security awareness training should be implemented to educate users about the risks of opening untrusted PDF files and visiting suspicious websites. The vulnerability demonstrates the importance of proper input validation and type safety in document processing applications, as highlighted in industry standards that recommend defensive programming practices to prevent such memory corruption vulnerabilities.