CVE-2018-9944 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.0.0.29935. 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 addLink 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 under the context of the current process. Was ZDI-CAN-5379.
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Analysis
by VulDB Data Team • 07/14/2024
The vulnerability identified as CVE-2018-9944 represents a critical remote code execution flaw affecting Foxit Reader version 9.0.0.29935 and potentially other versions within the same product line. This vulnerability operates under the principle of improper input validation, specifically manifesting in the addLink method where the software fails to properly validate object existence before performing operations on it. The flaw constitutes a classic null pointer dereference vulnerability that can be exploited by remote attackers to gain unauthorized code execution capabilities on affected systems. The vulnerability requires user interaction to be successfully exploited, meaning that targets must either visit a malicious webpage or open a specially crafted malicious file to trigger the vulnerable code path. This user interaction requirement places the vulnerability in the category of social engineering attacks where the attacker must convince the user to perform an action that leads to exploitation, making it particularly dangerous in targeted attack scenarios.
The technical implementation of this vulnerability stems from the absence of proper object validation mechanisms within the addLink method of the Foxit Reader application. When processing PDF documents, the software attempts to perform operations on objects without first confirming their existence or validity, creating a window of opportunity for attackers to manipulate the application's behavior. This flaw directly relates to CWE-476, which addresses NULL Pointer Dereference issues, and represents a failure in defensive programming practices. The vulnerability allows attackers to manipulate the application's memory operations and execute arbitrary code within the context of the current process, effectively granting them the same privileges as the Foxit Reader application itself. The exploitation chain typically involves crafting a malicious PDF file that contains specially designed objects and links that trigger the vulnerable addLink method when the document is opened or when specific user actions occur within the document.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with complete control over the affected system where Foxit Reader is installed. Since the execution occurs under the context of the current process, attackers can potentially access sensitive data, modify files, install malware, or establish persistence mechanisms within the target environment. This vulnerability particularly affects enterprise environments where Foxit Reader is commonly used for document processing, as it can serve as a vector for lateral movement or privilege escalation attacks. The fact that this vulnerability was tracked as ZDI-CAN-5379 indicates that it was recognized by the Zero Day Initiative and subjected to coordinated disclosure practices, highlighting its severity and potential for widespread exploitation across various attack surfaces. Organizations using Foxit Reader in production environments face significant risk from this vulnerability, as it can be exploited remotely without requiring authentication or specialized access to the target system.
Mitigation strategies for CVE-2018-9944 should focus on both immediate remediation and long-term defensive measures. The most effective immediate solution involves applying the vendor-provided security patches or updates that address the specific object validation flaw in the addLink method. System administrators should also implement network-based security controls such as web application firewalls and content filtering systems to prevent access to known malicious PDF files and websites. Additionally, user education and awareness programs should be enhanced to help users recognize potentially malicious content and avoid opening suspicious files. The vulnerability demonstrates the importance of input validation and defensive programming practices, which aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1203 for Exploitation for Client Execution. Organizations should also consider implementing sandboxing mechanisms for PDF processing and maintaining strict software update policies to ensure all vulnerable applications are promptly patched. Regular security assessments and vulnerability scanning should include checks for similar object validation flaws in other software applications to prevent similar issues from occurring in the broader attack surface.