CVE-2018-17616 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.0.1.5096. 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 handling of onBlur events. 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 in the context of the current process. Was ZDI-CAN-6334.
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Analysis
by VulDB Data Team • 06/03/2023
CVE-2018-17616 represents a critical remote code execution vulnerability affecting Foxit Reader version 9.0.1.5096, demonstrating a classic object validation flaw that aligns with CWE-476 which specifically addresses null pointer dereferences. This vulnerability operates through the improper handling of onBlur events within the PDF reader's JavaScript engine, where the application fails to validate whether an object reference exists before attempting operations on it. The flaw essentially creates a condition where an attacker can manipulate the application's behavior by triggering events that reference non-existent objects, leading to memory corruption and arbitrary code execution. The vulnerability requires user interaction to be exploited, meaning victims must either visit a malicious webpage containing crafted PDF content or open a specially crafted malicious file, making it particularly dangerous in phishing scenarios or targeted attacks.
The technical exploitation of this vulnerability occurs within the context of the PDF reader's event handling system, where the onBlur event mechanism does not properly validate object existence before proceeding with operations. This type of flaw falls under the broader category of heap-based buffer overflows and memory corruption vulnerabilities, which are commonly exploited through techniques such as return-oriented programming or direct code injection. The attack surface is particularly concerning because PDF readers like Foxit Reader operate with high privileges on user systems, and the successful exploitation allows attackers to execute code within the context of the current process, potentially leading to full system compromise. The vulnerability's classification as a remote code execution issue means that attackers can exploit it without requiring physical access to the target system, making it highly attractive for widespread deployment in malware campaigns.
From an operational impact perspective, this vulnerability poses significant risks to enterprise environments where Foxit Reader is commonly deployed as a standard PDF viewing solution. The requirement for user interaction makes it susceptible to social engineering attacks, where attackers can craft convincing phishing emails or malicious websites that trick users into opening compromised PDF files. The vulnerability's exploitation can lead to complete system compromise, data exfiltration, and persistence mechanisms being established within the victim's environment. Organizations using Foxit Reader versions prior to the patched release are particularly vulnerable, as the flaw exists in the core JavaScript processing engine that handles various PDF interactive elements. This vulnerability also demonstrates the importance of input validation and object lifecycle management in application security, as proper validation of object references before operations could have prevented the exploitation.
Mitigation strategies for CVE-2018-17616 should prioritize immediate patch deployment from Foxit Corporation, as the vendor has released updates addressing this specific flaw. Organizations should implement network-based protections such as web application firewalls and content filtering solutions to block access to known malicious PDF content and suspicious websites. Additionally, user education and awareness programs should emphasize the dangers of opening PDF files from untrusted sources, particularly those received via email or downloaded from unknown websites. Security teams should also consider implementing sandboxing mechanisms for PDF processing and monitoring for suspicious JavaScript activity within PDF documents. The vulnerability's characteristics align with ATT&CK technique T1059.007 for JavaScript-based attacks and T1203 for exploitation of web applications, making it important for security operations centers to monitor for these specific attack patterns. Organizations should also conduct regular vulnerability assessments and penetration testing to identify similar flaws in other PDF readers or document processing applications within their environment, as similar vulnerabilities may exist in other software components that handle similar event-driven processing mechanisms.