CVE-2018-17672 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 array indices. 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-6817.
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Analysis
by VulDB Data Team • 05/05/2020
CVE-2018-17672 represents a critical buffer overflow vulnerability affecting Foxit Reader version 9.2.0.9297 that enables remote code execution through improper array index validation. This vulnerability falls under the CWE-129 weakness category, specifically addressing insufficient validation of array indices which creates opportunities for attackers to manipulate memory access patterns. The flaw manifests when the application processes maliciously crafted PDF files or web pages that contain malformed array structures, allowing attackers to bypass normal execution flow and inject malicious code. The vulnerability requires user interaction to exploit, meaning a victim must either visit a compromised webpage or open a malicious PDF document for the attack to succeed. This attack vector aligns with the ATT&CK technique T1203 - Exploitation for Client Execution, where adversaries leverage application vulnerabilities to execute code on target systems.
The technical implementation of this vulnerability stems from inadequate input validation within the PDF parsing engine of Foxit Reader. When processing array elements, the application fails to verify whether array indices reference valid memory locations before attempting to access or manipulate the referenced data. This oversight creates a classic out-of-bounds memory access scenario where attackers can craft malicious array structures that cause the application to read or write data beyond allocated memory boundaries. The lack of proper bounds checking allows attackers to manipulate the program's execution flow by overwriting critical memory locations such as return addresses or function pointers. The vulnerability exists in the context of the application's object model handling, where objects are referenced through array indices without proper validation of object existence or memory integrity.
The operational impact of this vulnerability extends beyond simple code execution to potentially compromise entire user systems. When successfully exploited, the vulnerability allows attackers to execute arbitrary code with the privileges of the currently running Foxit Reader process, which typically runs with the user's local permissions. This creates opportunities for privilege escalation attacks, lateral movement within network environments, and data exfiltration. The vulnerability's remote exploitation capability makes it particularly dangerous as attackers can distribute malicious content through web-based attacks or phishing campaigns without requiring physical access to target systems. The attack surface is broad since Foxit Reader is widely deployed in enterprise environments, making the vulnerability attractive to threat actors seeking to compromise multiple systems simultaneously.
Mitigation strategies for CVE-2018-17672 should focus on immediate patch deployment and operational security enhancements. Organizations must prioritize updating Foxit Reader installations to versions that address this vulnerability, as the vendor released patches specifically targeting the array index validation flaw. Network-based mitigations include implementing web filtering solutions that block access to known malicious domains and content sources, while endpoint protection measures should include sandboxing PDF processing and monitoring for suspicious file access patterns. Security teams should also consider implementing application whitelisting policies that restrict execution of unauthorized PDF readers or processing components. The vulnerability's characteristics align with ATT&CK technique T1190 - Exploit Public-Facing Application, highlighting the importance of maintaining current application versions and implementing robust patch management processes. Additionally, user education regarding suspicious web content and file attachments remains crucial since the vulnerability requires user interaction to exploit, making social engineering components of attacks particularly relevant to the overall threat landscape.