CVE-2017-14824 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 insert method of XFAScriptObject objects. The issue results from the lack of proper validation of user-supplied data, which can result in a type confusion condition. An attacker can leverage this vulnerability to execute code under the context of the current process. Was ZDI-CAN-5016.
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Analysis
by VulDB Data Team • 12/16/2019
The vulnerability identified as CVE-2017-14824 represents a critical security flaw in Foxit Reader version 8.3.1.21155 that enables remote code execution through a type confusion vulnerability within the XFAScriptObject insert method. This vulnerability operates under the CWE-476 principle of null pointer dereference and falls under the ATT&CK technique of T1059.007 for command and scripting interpreter, specifically targeting the execution of arbitrary code through script manipulation. The flaw exists in the application's handling of user-supplied data within the XFA scripting engine, which is responsible for processing XML Forms Architecture documents that are commonly embedded in PDF files.
The technical implementation of this vulnerability stems from insufficient input validation within the XFAScriptObject's insert method, where the application fails to properly validate or sanitize user-supplied parameters before processing them. This lack of proper validation creates a type confusion condition that allows attackers to manipulate the application's memory management and execution flow. When a malicious user visits a compromised webpage or opens a specially crafted PDF file containing malicious XFA scripts, the vulnerable code path is triggered. The type confusion occurs because the application incorrectly handles data type assumptions during script execution, potentially leading to memory corruption that can be exploited to gain control over the application's execution context. The vulnerability specifically affects the process execution context, allowing attackers to run code with the privileges of the current user running Foxit Reader.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete system compromise when attackers leverage additional attack vectors. An attacker can exploit this vulnerability to execute malicious code on the victim's system, potentially leading to unauthorized access, data exfiltration, or further network penetration. The requirement for user interaction through visiting malicious pages or opening malicious files means that this vulnerability operates within the realm of social engineering attacks, where users are tricked into executing the malicious payload. The vulnerability's exploitation typically requires the victim to have Foxit Reader installed and to interact with the malicious content, making it particularly dangerous in targeted attacks where attackers can craft convincing social engineering campaigns. The impact is amplified when considering that Foxit Reader is widely used for document viewing, making it an attractive target for attackers seeking to compromise user systems through document-based attacks.
Mitigation strategies for CVE-2017-14824 should include immediate patching of Foxit Reader to version 8.3.2 or later, which contains the necessary fixes for the type confusion vulnerability. Organizations should implement strict content filtering and sandboxing measures for PDF files, particularly those received from untrusted sources or external entities. Network administrators should consider implementing web application firewalls and content inspection systems to detect and block malicious XFA script content. Security teams should also conduct regular vulnerability assessments and penetration testing to identify potentially vulnerable installations within their networks. The implementation of principle of least privilege should be enforced, ensuring that Foxit Reader operates with minimal required permissions. Additionally, user education and awareness programs should be strengthened to help users recognize potentially malicious content and avoid visiting compromised websites or opening suspicious PDF files. The vulnerability also highlights the importance of regular software updates and patch management processes, as this flaw existed in a widely distributed version of the software. Organizations should also consider implementing endpoint detection and response solutions that can monitor for suspicious process execution patterns or memory manipulation activities that might indicate exploitation attempts.