CVE-2018-9965 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.0.1.1049. 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 the setAction method of Link 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-5569.
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Analysis
by VulDB Data Team • 02/06/2020
The vulnerability identified as CVE-2018-9965 represents a critical remote code execution flaw in Foxit Reader version 9.0.1.1049 that demonstrates a classic object validation error pattern commonly associated with memory safety issues. This vulnerability resides within the PDF reader's handling of hyperlink objects, specifically in the setAction method of Link objects where insufficient input validation permits malicious actors to manipulate object references without proper existence verification. The flaw operates under the CWE-476 principle of null pointer dereference, where the application assumes object validity without performing necessary checks before execution. Attackers can exploit this weakness by crafting malicious PDF documents or web pages that trigger the vulnerable code path when the targeted system processes these objects, making it particularly dangerous in environments where users frequently interact with untrusted PDF content.
The technical implementation of this vulnerability exploits the fundamental principle of object-oriented programming where a method attempts to operate on an object reference without verifying whether that reference points to a valid object instance. When Foxit Reader processes a PDF document containing a maliciously crafted Link object, the setAction method executes without proper validation of the object's existence, leading to a potential memory corruption scenario. This type of vulnerability falls under the ATT&CK technique T1059.007 for command and scripting interpreter and T1203 for exploitation for execution, as it allows remote code execution through the manipulation of PDF parsing routines. The vulnerability requires user interaction to be successful, meaning that victims must either visit a malicious webpage hosting a compromised PDF or open a maliciously crafted PDF file, which aligns with the attack pattern described in the ZDI-CAN-5569 advisory.
The operational impact of CVE-2018-9965 extends beyond simple code execution, as successful exploitation allows attackers to operate within the security context of the currently running Foxit Reader process. This privilege escalation capability can potentially lead to complete system compromise depending on the user's privileges and the system configuration. The vulnerability's remote nature makes it particularly attractive to threat actors who can deploy exploits through web-based attack vectors, including phishing campaigns or compromised websites. Organizations using Foxit Reader in enterprise environments face significant risk as this vulnerability could enable attackers to establish persistent access points, escalate privileges, or deploy additional malware components. The vulnerability's classification as a remote code execution flaw means that network-based attacks can be launched without requiring physical access to target systems, making it a high-priority concern for security teams managing document processing environments.
Mitigation strategies for this vulnerability should focus on immediate patching of affected Foxit Reader installations to version 9.0.1.1050 or later, which contains the necessary fixes for the object validation issue. Security administrators should implement network-based controls such as web application firewalls and content filtering solutions to block access to known malicious PDF content. Additionally, user education programs should emphasize the importance of only opening PDF files from trusted sources and avoiding suspicious web links that may lead to compromised content. The vulnerability demonstrates the importance of input validation and object safety checks in document processing software, reinforcing the need for robust security practices in PDF rendering engines. Organizations should also consider implementing sandboxing mechanisms for PDF processing and monitoring for unusual process behavior that might indicate exploitation attempts, particularly in environments where PDF documents are frequently processed or shared.