CVE-2018-21244 in PhantomPDF
Summary
by MITRE
An issue was discovered in Foxit PhantomPDF before 8.3.6. It allows arbitrary application execution via an embedded executable file in a PDF portfolio, aka FG-VD-18-029.
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Analysis
by VulDB Data Team • 10/22/2020
The vulnerability identified as CVE-2018-21244 represents a critical security flaw in Foxit PhantomPDF software versions prior to 8.3.6, specifically affecting the handling of PDF portfolio documents that contain embedded executable files. This vulnerability falls under the category of arbitrary code execution, which is a severe class of security issues that can allow attackers to execute malicious code on a victim's system without their knowledge or consent. The flaw exists within the PDF portfolio processing functionality of the software, where the application fails to properly validate or sanitize embedded files before execution. This particular vulnerability was assigned the identifier FG-VD-18-029 by Foxit's security team, indicating it was recognized and documented as a significant risk to user security. The vulnerability is particularly concerning because PDF portfolios are commonly used to package multiple documents together, making them a legitimate and widely accepted document format in professional and business environments.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the PDF portfolio handling mechanism of Foxit PhantomPDF. When a user opens a PDF portfolio containing an embedded executable file, the software does not adequately verify the nature of the embedded content or implement proper security controls to prevent automatic execution of potentially malicious binaries. This flaw allows attackers to craft malicious PDF portfolio documents that contain hidden or disguised executable files, which are then executed automatically when the portfolio is opened. The vulnerability is classified as a privilege escalation issue since it allows attackers to execute code with the privileges of the user running the vulnerable software, potentially leading to complete system compromise. This type of vulnerability is particularly dangerous because it exploits the trust users place in PDF documents, which are commonly opened without suspicion in business and academic environments where PDF portfolios are frequently shared.
The operational impact of CVE-2018-21244 extends far beyond simple code execution, as it can lead to complete system compromise and data theft. When exploited, this vulnerability allows attackers to install malware, steal sensitive information, or establish persistent backdoors on affected systems. The attack vector is particularly insidious because it requires no special privileges or complex social engineering beyond tricking users into opening a malicious PDF portfolio document. This makes the vulnerability highly effective in phishing campaigns and targeted attacks against organizations. The risk is amplified by the widespread use of Foxit PhantomPDF across various industries, including government, finance, and healthcare sectors where sensitive data is commonly processed. Organizations using affected versions of the software face significant exposure to data breaches, regulatory violations, and potential legal consequences due to the lack of proper security controls. The vulnerability can be exploited remotely through email attachments, web downloads, or any method of distributing malicious PDF portfolio files to unsuspecting users.
Mitigation strategies for CVE-2018-21244 primarily focus on immediate software updates and operational security measures. The most effective solution is to upgrade to Foxit PhantomPDF version 8.3.6 or later, which contains patches specifically addressing the embedded executable handling vulnerability. Organizations should implement comprehensive patch management procedures to ensure all systems running Foxit PhantomPDF are updated promptly. Additionally, security administrators should consider implementing strict file type restrictions and content filtering for PDF portfolio documents, particularly in high-security environments. Network-based security controls such as web application firewalls and email security gateways can help detect and block malicious PDF portfolio files before they reach end users. The vulnerability aligns with attack patterns documented in the mitre ATT&CK framework under techniques involving execution through compromised applications and social engineering. Organizations should also consider implementing user education programs to raise awareness about the risks of opening unexpected PDF files, particularly those containing embedded content. Regular security audits and vulnerability assessments should be conducted to identify any remaining instances of the vulnerable software within the organization's infrastructure.