CVE-2018-17675 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.2.0.9297. 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 removeDataObject method of a document. 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-6848.
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Analysis
by VulDB Data Team • 05/05/2020
CVE-2018-17675 represents a critical code execution vulnerability affecting Foxit Reader version 9.2.0.9297 that demonstrates a classic improper input validation flaw categorized under CWE-20. The vulnerability stems from insufficient validation within the removeDataObject method of PDF document processing functionality where the application fails to verify whether a target object exists before attempting operations on it. This fundamental flaw creates a condition where an attacker can manipulate the document parsing logic to trigger unintended code execution. The vulnerability requires user interaction to exploit, meaning a victim must either visit a malicious web page or open a crafted malicious file containing the vulnerable PDF content. This attack vector aligns with ATT&CK technique T1203, which involves gaining access through malicious documents, and T1059, which covers command and scripting interpreter usage. The lack of proper object existence validation creates a path for attackers to manipulate the application's memory management and potentially escalate privileges to the same level as the running Foxit Reader process. This type of vulnerability is particularly dangerous in enterprise environments where PDF readers are frequently used for document sharing and business communications, as it can serve as an initial access point for more sophisticated attacks.
The technical implementation of this vulnerability exploits the absence of pre-checks for object existence within the document processing pipeline. When Foxit Reader attempts to remove a data object that has not been properly initialized or has already been freed, the application's memory management routines become unstable. This condition can be leveraged through carefully crafted PDF files that contain malformed object references designed to trigger the vulnerable code path. The exploitation process typically involves constructing a malicious PDF document with specially crafted object structures that cause the removeDataObject method to execute with controlled parameters, ultimately leading to arbitrary code execution. The vulnerability's impact extends beyond simple code execution as it can be combined with other techniques to achieve persistent access or escalate privileges. According to industry best practices for secure coding, this type of vulnerability should be addressed through proper input validation, object lifetime management, and defensive programming practices that prevent use-after-free conditions. The vulnerability's classification under ZDI-CAN-6848 indicates it was recognized by the Zero Day Initiative and addressed through coordinated disclosure practices.
Organizations affected by CVE-2018-17675 must implement immediate mitigations to protect their systems from potential exploitation attempts. The primary recommendation involves updating to the latest version of Foxit Reader where the vulnerability has been patched through proper object validation mechanisms. Until updates are applied, administrators should implement network-based controls such as web application firewalls and PDF content filtering solutions to block malicious documents from entering the network. User education remains critical as employees must be trained to recognize suspicious email attachments and web links that could contain malicious PDF content. Security teams should also consider implementing sandboxing techniques for PDF processing and monitoring for unusual network activity that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper memory management in document processing applications and highlights the need for regular security assessments of third-party software components. Organizations should also review their patch management processes to ensure timely application of security updates and consider implementing automated vulnerability scanning to identify systems running vulnerable versions of Foxit Reader. This vulnerability serves as a reminder of the critical nature of input validation and proper error handling in security-sensitive applications, particularly those handling untrusted data such as PDF documents.