CVE-2019-20813 in PhantomPDF
Summary
by MITRE
An issue was discovered in Foxit PhantomPDF before 8.3.12. It has a NULL pointer dereference.
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Analysis
by VulDB Data Team • 10/22/2020
The vulnerability identified as CVE-2019-20813 represents a critical NULL pointer dereference flaw within Foxit PhantomPDF software versions prior to 8.3.12. This issue manifests when the application processes malformed or specially crafted PDF documents that contain specific structural elements or metadata. The flaw occurs during the parsing and rendering phases of PDF document handling, where the software fails to properly validate pointer references before attempting to access memory locations. Such NULL pointer dereference conditions are particularly dangerous because they can lead to application crashes or, in more sophisticated exploitation scenarios, provide attackers with opportunities to execute arbitrary code or escalate privileges within the affected system environment.
The technical implementation of this vulnerability stems from inadequate input validation mechanisms within the PDF processing engine of Foxit PhantomPDF. When encountering certain malformed PDF objects or streams, the application's parser attempts to dereference a pointer that has not been properly initialized or validated, resulting in a segmentation fault or access violation. This type of vulnerability falls under the CWE-476 category of NULL Pointer Dereference, which is classified as a fundamental programming error that occurs when a program attempts to access memory through a pointer that has a value of NULL. The flaw is particularly concerning because PDF documents are commonly shared across networks and email systems, making this vulnerability exploitable through social engineering campaigns or automated malicious document delivery mechanisms.
From an operational impact perspective, this vulnerability creates significant risks for organizations relying on Foxit PhantomPDF for document processing and viewing. The NULL pointer dereference can cause unexpected application termination, leading to productivity losses and potential data access interruptions. In enterprise environments where PDF processing is automated or integrated into business workflows, this vulnerability could result in service disruptions or denial of access to critical document repositories. Security analysts have noted that while the immediate impact may appear limited to application crashes, the underlying flaw could potentially be leveraged in combination with other vulnerabilities to achieve more severe outcomes such as privilege escalation or remote code execution. The vulnerability also raises concerns about the overall security posture of organizations that may be unaware of the specific version of software they are running, as it demonstrates the importance of maintaining current software patches and implementing robust vulnerability management processes.
The remediation strategy for CVE-2019-20813 centers on upgrading to Foxit PhantomPDF version 8.3.12 or later, which includes proper pointer validation mechanisms and enhanced input sanitization routines. Organizations should conduct immediate vulnerability assessments to identify all systems running affected versions of the software and prioritize patch deployment across their networks. Security teams should also implement monitoring solutions to detect potential exploitation attempts targeting this vulnerability, particularly in environments where PDF documents are frequently processed or shared. Additionally, network administrators should consider implementing email filtering and web proxy configurations that can block or quarantine suspicious PDF attachments, aligning with the ATT&CK framework's recommendations for defending against initial access vectors through malicious document delivery. The vulnerability underscores the importance of maintaining up-to-date software inventory and implementing automated patch management systems to prevent similar issues from affecting organizational security postures.