CVE-2018-17630 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.1.0.5096. 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 openPlayer 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 in the context of the current process. Was ZDI-CAN-6616.
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Analysis
by VulDB Data Team • 05/05/2020
CVE-2018-17630 represents a critical buffer overflow vulnerability in Foxit Reader version 9.1.0.5096 that enables remote code execution through improper object validation during the openPlayer method processing. This vulnerability falls under the CWE-476 category of Null Pointer Dereference, where the application fails to validate object existence before executing operations on it. The flaw occurs when the PDF reader processes maliciously crafted content that triggers the openPlayer method, which does not properly validate whether the target object exists in memory before attempting to access or manipulate it. This allows attackers to craft malicious PDF files or web pages that, when opened or viewed by an unsuspecting user, will trigger the vulnerable code path and execute arbitrary machine code within the context of the Foxit Reader process. The vulnerability requires user interaction to exploit, as victims must either visit a malicious webpage or open a specially crafted PDF file containing the malicious payload. The attack leverages the principle of privilege escalation by executing code with the same privileges as the vulnerable application, potentially allowing attackers to gain unauthorized access to the victim's system. According to ATT&CK framework, this vulnerability maps to T1059.007 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, as the code execution occurs within the application context and could potentially be used to escalate privileges further. The exploitation chain typically involves crafting a malicious PDF document that contains JavaScript code or embedded objects designed to trigger the vulnerable openPlayer method. When the user opens this document, the PDF parser processes the malicious content and calls the vulnerable method without proper null checks, leading to memory corruption and arbitrary code execution. This vulnerability demonstrates the critical importance of input validation and proper object lifecycle management in PDF processing applications, as similar flaws have been identified in other PDF readers and document processing software. The issue was tracked as ZDI-CAN-6616, highlighting the coordinated vulnerability disclosure approach used by Zero Day Initiative to manage the vulnerability lifecycle from discovery to patch release.
The technical implementation of this vulnerability involves a classic null pointer dereference scenario where the openPlayer method fails to verify object existence before attempting operations. This type of flaw commonly occurs in applications that process untrusted input data, particularly in complex document formats like PDFs where multiple object types and methods are invoked during parsing. The lack of proper validation creates an opportunity for attackers to manipulate the application's memory state through carefully crafted input that causes the program to access invalid memory locations, potentially leading to stack corruption, heap manipulation, or other memory-based exploits. The vulnerability's remote exploitability stems from the fact that PDF documents can be delivered through various vectors including web browsers, email attachments, or web-based PDF viewers, making it particularly dangerous for enterprise environments. Security researchers have noted that similar vulnerabilities in PDF processing applications often result in similar exploitation patterns, where attackers leverage the complexity of PDF parsing to find and abuse validation gaps in object handling. The impact of successful exploitation includes complete system compromise, as the code executes within the context of the Foxit Reader process, which typically has access to the user's file system and can potentially escalate privileges if the application is running with elevated permissions.
Mitigation strategies for CVE-2018-17630 should include immediate patching of Foxit Reader installations to version 9.1.1 or later, which contains the necessary fixes for the object validation issue in the openPlayer method. Organizations should also implement network-based security controls such as web application firewalls and PDF content filtering systems that can detect and block malicious PDF files before they reach end users. User education and awareness programs should emphasize the importance of only opening PDF files from trusted sources and avoiding suspicious email attachments or web links. Additional protective measures include running Foxit Reader with restricted privileges, implementing application whitelisting policies, and using sandboxing technologies to isolate PDF processing activities from the rest of the system. Security monitoring should focus on detecting unusual PDF processing activities or unexpected network connections from Foxit Reader processes, as these could indicate exploitation attempts. Organizations should also consider deploying endpoint detection and response solutions that can identify and block malicious code execution patterns associated with this vulnerability. The remediation process should include comprehensive vulnerability scanning to identify all affected systems and ensure that the patches have been properly applied. Regular security assessments of document processing applications should be conducted to identify similar validation gaps that could lead to similar vulnerabilities. Given the nature of the vulnerability, it is recommended that organizations implement multiple layers of defense including network segmentation, access controls, and regular security updates to protect against this and related exploitation techniques. The vulnerability serves as a reminder of the importance of secure coding practices and proper input validation in applications that process complex file formats, particularly those used in enterprise environments where security is paramount.