CVE-2018-9970 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.0.1.1049. 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 XFA execEvent method of Button elements. 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-5580.
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Analysis
by VulDB Data Team • 08/15/2024
CVE-2018-9970 represents a critical remote code execution vulnerability affecting Foxit Reader version 9.0.1.1049 that demonstrates a classic object validation flaw in Adobe's XML Forms Architecture implementation. This vulnerability resides within the XFA execEvent method of Button elements, where the application fails to properly validate whether an object exists before attempting operations on it. The flaw constitutes a direct violation of CWE-476 which defines null pointer dereference conditions, and more specifically aligns with CWE-119 which addresses memory corruption issues arising from improper input validation. The vulnerability operates under the ATT&CK framework's technique T1059.007 for command and scripting interpreter, as exploitation requires the execution of malicious code within the context of the vulnerable application's process.
The technical implementation of this vulnerability exploits the lack of proper object existence checking during XFA form processing, particularly when handling Button elements that invoke the execEvent method. When a malicious page or file containing crafted XFA content is opened, the application attempts to execute operations on a non-existent object reference, creating a condition where memory corruption occurs. This memory corruption allows attackers to inject and execute arbitrary code with the privileges of the current process, effectively providing a complete system compromise vector. The vulnerability requires user interaction through visiting a malicious webpage or opening a malicious PDF file, making it particularly dangerous in targeted attack scenarios where social engineering can be employed to deliver the malicious payload.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with persistent access to the victim's system through the context of the Foxit Reader process. This allows for privilege escalation attacks, data exfiltration, and further network reconnaissance activities. The vulnerability's exploitation aligns with ATT&CK technique T1068 which covers local privilege escalation, and T1005 which addresses data from local system. Security professionals must understand that this vulnerability represents a significant risk to enterprise environments where Foxit Reader is commonly deployed for document viewing, as it can be exploited through web browsers or email attachments without requiring administrative privileges. The vulnerability's presence in a widely used PDF reader application makes it particularly attractive to threat actors seeking persistent access to target networks.
Mitigation strategies for CVE-2018-9970 should include immediate patching of Foxit Reader to versions that address the XFA object validation issue. Organizations should implement network-based protections such as web application firewalls and content filtering to block access to malicious PDF content. Additionally, user education regarding the dangers of opening suspicious PDF files and visiting untrusted websites remains crucial. Security teams should monitor for exploitation attempts through network traffic analysis and endpoint detection systems. The vulnerability's classification under CWE-476 and its exploitation patterns align with common attack vectors in the cybersecurity landscape, making it essential for organizations to maintain updated threat intelligence feeds and implement layered security controls to prevent successful exploitation. Regular security assessments should verify that all instances of Foxit Reader are patched and that proper access controls are in place to limit potential attack surface exposure.