CVE-2017-14832 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 8.3.1.21155. 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 style attribute of Caret Annotation objects. 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-5024.
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Analysis
by VulDB Data Team • 12/16/2019
The vulnerability identified as CVE-2017-14832 represents a critical remote code execution flaw affecting Foxit Reader version 8.3.1.21155, demonstrating a classic object-oriented programming error that has significant implications for document security. This vulnerability falls under CWE-476 which specifically addresses NULL pointer dereferences, where the software fails to validate the existence of an object before attempting operations on it. The flaw manifests within the Caret Annotation objects' style attribute processing, creating a scenario where an attacker can manipulate the PDF parsing logic to execute arbitrary code on the target system. The vulnerability requires user interaction to be exploited, meaning that a victim must either visit a malicious webpage or open a crafted malicious file containing the vulnerable annotation structure, making this attack vector particularly insidious in social engineering campaigns.
The technical implementation of this vulnerability stems from improper input validation within Foxit Reader's PDF parsing engine, specifically when handling Caret Annotation objects that contain style attributes. When the reader encounters a malformed or maliciously constructed Caret Annotation, it attempts to process the style attribute without first verifying that the underlying object reference is valid. This lack of proper validation creates a condition where the application can be coerced into executing code in the context of the current process, effectively allowing an attacker to gain the same privileges as the user running the vulnerable software. The attack surface is particularly concerning because PDF readers are commonly used applications that users trust, making successful exploitation a significant security risk. According to ATT&CK framework category T1203, this vulnerability enables an attacker to gain access to a system through legitimate user access, while also mapping to T1059 which covers command and scripting interpreter usage for code execution.
The operational impact of CVE-2017-14832 extends beyond simple code execution, as it represents a privilege escalation opportunity that can lead to complete system compromise when combined with other attack vectors. The vulnerability exists in the parsing layer of the PDF reader, which means that even documents that appear benign can contain hidden malicious code that triggers during normal document rendering operations. This characteristic makes the vulnerability particularly dangerous in enterprise environments where PDF documents are frequently shared and opened by multiple users. The fact that exploitation requires user interaction does not mitigate the risk significantly, as social engineering campaigns can easily convince users to open seemingly legitimate documents. Organizations should consider this vulnerability as part of a broader attack surface that includes web-based attacks, file-sharing systems, and email attachments, all of which can serve as delivery mechanisms for malicious PDF content.
Mitigation strategies for CVE-2017-14832 should focus on both immediate remediation and long-term security hardening measures. The most effective immediate solution involves updating Foxit Reader to a patched version that properly validates object references before processing them, which would address the underlying CWE-476 issue. Organizations should also implement content filtering solutions that can detect and block potentially malicious PDF documents before they reach end users. Network-based security controls including web application firewalls and intrusion prevention systems can help detect and prevent exploitation attempts by monitoring for suspicious PDF parsing patterns. Additionally, user education programs should emphasize the importance of only opening PDF documents from trusted sources and should include awareness training about social engineering techniques that attackers might use to deliver malicious content. From a defensive perspective, organizations should consider implementing sandboxing mechanisms for PDF processing, which can isolate potentially malicious content and prevent it from affecting the primary system. The vulnerability also highlights the importance of regular security assessments and penetration testing to identify similar issues in other document processing applications and ensure comprehensive protection against similar attack vectors.