CVE-2019-20825 in PhantomPDF
Summary
by MITRE
An issue was discovered in Foxit PhantomPDF before 8.3.11. It has an out-of-bounds write when Internet Explorer is used.
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Analysis
by VulDB Data Team • 10/22/2020
The vulnerability identified as CVE-2019-20825 represents a critical out-of-bounds write flaw affecting Foxit PhantomPDF versions prior to 8.3.11 when operating in Internet Explorer environments. This security defect manifests specifically within the PDF rendering engine's handling of certain document elements, creating a potential avenue for arbitrary code execution and system compromise. The issue stems from insufficient input validation and memory management practices within the software's integration with Microsoft's Internet Explorer browser platform.
This vulnerability falls under the CWE-787 category of out-of-bounds write conditions, where the application attempts to write data beyond the allocated memory boundaries of a buffer or array. The flaw occurs during the processing of PDF documents that contain maliciously crafted elements designed to trigger the buffer overflow condition. When Internet Explorer renders these documents through the Foxit PhantomPDF plugin, the improper memory handling allows attackers to manipulate the program's execution flow and potentially execute malicious code with the privileges of the affected user.
The operational impact of CVE-2019-20825 extends beyond simple document rendering failures, as it creates a persistent threat vector for attackers seeking to compromise systems running vulnerable versions of Foxit PhantomPDF. Organizations utilizing this software in enterprise environments face significant risk exposure, particularly when users regularly access untrusted PDF content through Internet Explorer. The vulnerability's exploitation potential aligns with ATT&CK technique T1203, which involves the use of malicious documents to gain initial access or execute code within target systems. Attackers could leverage this flaw to deliver malware payloads, establish persistent backdoors, or escalate privileges within compromised environments.
Mitigation strategies for this vulnerability require immediate patch deployment to upgrade Foxit PhantomPDF to version 8.3.11 or later, which incorporates proper bounds checking and memory management protections. Organizations should also implement browser security policies that restrict PDF plugin usage, particularly in high-risk environments where users may encounter untrusted content. Network-based defenses such as web application firewalls and content filtering systems can provide additional layers of protection by blocking suspicious PDF content before it reaches vulnerable systems. Security teams should monitor for exploitation attempts through network traffic analysis and endpoint detection systems, as the vulnerability may be exploited through phishing campaigns or malicious website content. The remediation process must include comprehensive testing of the updated software to ensure compatibility with existing document workflows while maintaining security posture against similar memory corruption vulnerabilities.