CVE-2018-17639 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 setElement 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-6475.
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Analysis
by VulDB Data Team • 05/05/2020
CVE-2018-17639 represents a critical remote code execution vulnerability affecting Foxit Reader version 9.2.0.9297, classified under CWE-476 Null Pointer Dereference, which falls within the broader category of memory safety issues. This vulnerability stems from improper input validation within the setElement method implementation, where the application fails to verify whether an object reference exists before attempting to operate on it. The flaw creates a condition where a null pointer dereference occurs, potentially leading to arbitrary code execution with the privileges of the current process. This vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, as exploitation could enable attackers to execute malicious commands through the compromised application.
The technical exploitation of this vulnerability requires user interaction, making it a client-side attack vector that typically involves social engineering tactics. Attackers can craft malicious web pages or PDF documents containing specially crafted payloads that trigger the vulnerable setElement method when the target opens the malicious content. The lack of proper object validation creates a predictable execution flow where the application attempts to access memory locations that have not been properly initialized, leading to potential memory corruption and code execution. This type of vulnerability is particularly dangerous because it allows attackers to bypass traditional security controls that might be in place, as the exploitation occurs within the legitimate application context.
From an operational impact perspective, this vulnerability poses significant risks to organizations relying on Foxit Reader for document processing and viewing. The remote execution capability means that attackers can compromise systems without requiring physical access or additional authentication, making it particularly attractive for large-scale attacks. The vulnerability affects not only individual users but also enterprise environments where Foxit Reader is deployed across multiple systems, potentially enabling lateral movement within networks. The exploitation process leverages the application's legitimate functionality to execute malicious code, making detection more challenging for traditional security solutions that might not identify such attacks as suspicious.
Organizations should implement immediate mitigations including updating to the latest version of Foxit Reader that addresses this vulnerability, as well as deploying network-based protections such as web application firewalls and content filtering solutions. Security teams should also consider implementing user education programs to reduce the risk of social engineering attacks that could lead to exploitation. Additionally, monitoring for unusual PDF processing activities and implementing least privilege principles for application execution can help reduce the potential impact of successful exploitation attempts. The vulnerability demonstrates the importance of proper input validation and object lifecycle management in preventing memory safety issues that could lead to full system compromise.