CVE-2018-17645 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 vAlign property of a TimeField. 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-6482.
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Analysis
by VulDB Data Team • 05/05/2020
CVE-2018-17645 represents a critical remote code execution vulnerability affecting Foxit Reader version 9.2.0.9297, demonstrating a classic object traversal flaw that aligns with CWE-476. This vulnerability operates through the improper validation of object existence within the TimeField's vAlign property handling, creating a dangerous condition where an attacker can manipulate the application's memory operations without proper bounds checking. The flaw specifically manifests when the application attempts to perform operations on an object that has not been properly initialized or validated, leading to potential memory corruption that can be exploited for arbitrary code execution. The vulnerability requires user interaction to be exploited, meaning that a malicious webpage or file must be visited or opened by an unsuspecting user, which makes this attack vector particularly concerning in social engineering scenarios.
The technical exploitation of this vulnerability follows a predictable pattern that aligns with common exploit methodologies documented in the ATT&CK framework under technique T1203. When Foxit Reader processes a malicious PDF containing a crafted TimeField element with an improperly validated vAlign property, the application's parsing logic fails to verify object existence before attempting to access or manipulate the object's properties. This validation gap allows an attacker to craft a malicious document that triggers a heap-based buffer overflow or other memory corruption conditions. The vulnerability exists because the application's object model does not implement proper null pointer checks or object lifecycle validation, creating an exploitable condition that can be leveraged to redirect execution flow or inject malicious code into the running process.
The operational impact of CVE-2018-17645 extends beyond simple code execution, as it represents a complete compromise of the affected system's security posture. When successfully exploited, the vulnerability allows attackers to execute code with the privileges of the Foxit Reader process, which typically runs with the same permissions as the user who opened the malicious document. This creates a significant risk for enterprise environments where users may have elevated privileges, potentially allowing attackers to escalate their access to system-level privileges or establish persistent backdoors. The vulnerability's remote exploitation capability means that attackers can deliver malicious payloads through web browsers, email attachments, or file sharing systems without requiring physical access to the target system, making it particularly dangerous for organizations with limited network segmentation.
Mitigation strategies for CVE-2018-17645 should focus on both immediate remediation and long-term security hardening measures. Organizations should prioritize updating to Foxit Reader version 9.2.1 or later, which contains the necessary patches to address the object validation flaw in the TimeField handling code. Additionally, network administrators should implement web filtering controls and email security solutions that can detect and block malicious PDF files containing suspicious TimeField elements. The vulnerability's characteristics make it suitable for exploitation through multiple attack vectors, so security teams should consider implementing sandboxing mechanisms for PDF processing and monitoring for unusual network activity that might indicate exploitation attempts. Organizations should also conduct security awareness training to help users recognize potentially malicious documents and avoid visiting untrusted websites that might host exploit code. From a defensive perspective, the vulnerability demonstrates the importance of proper input validation and object lifecycle management in preventing remote code execution flaws, aligning with security best practices outlined in both CWE guidelines and industry standards for secure coding practices.