CVE-2018-17654 in Foxit
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.2.0.9297. 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 insertInstance method of a Form object. 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-6504.
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Analysis
by VulDB Data Team • 05/05/2020
This vulnerability in Foxit Reader 9.2.0.9297 represents a critical remote code execution flaw that demonstrates poor input validation practices in the application's form handling mechanisms. The vulnerability specifically resides in the insertInstance method of Form objects where the software fails to properly validate whether an object exists before attempting operations on it. This type of flaw falls under the CWE-476 category of NULL Pointer Dereference, which is a common class of vulnerabilities that can be exploited to gain unauthorized access to system resources. The vulnerability's remote exploitation capability means that attackers can trigger the flaw through web-based attacks without requiring local system access, making it particularly dangerous in enterprise environments where users frequently browse the internet or open documents from untrusted sources.
The technical implementation of this vulnerability stems from inadequate object validation within the form processing subsystem of Foxit Reader. When processing maliciously crafted form data, the application attempts to perform operations on what it believes to be a valid object instance but which may have been improperly initialized or deliberately constructed to exploit the validation gap. This allows an attacker to manipulate the application's execution flow by controlling the memory layout or object references, potentially leading to arbitrary code execution within the context of the current process. The vulnerability requires user interaction through visiting a malicious webpage or opening a malicious file, which aligns with the attack pattern described in the attack tree model where initial access is gained through social engineering or compromised web content. The ZDI-CAN-6504 reference indicates this vulnerability was identified and tracked by the Zero Day Initiative, highlighting its significance in the cybersecurity community and its potential for widespread exploitation.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise, as the attacker can leverage the elevated privileges of the Foxit Reader process to perform malicious activities. This includes but is not limited to data exfiltration, privilege escalation, and the installation of additional malware payloads. The vulnerability's exploitation is particularly concerning in enterprise environments where Foxit Reader is commonly used for document viewing, as it provides a vector for attackers to compromise multiple systems through a single successful attack. Organizations using vulnerable versions of Foxit Reader are exposed to potential lateral movement within their networks, as the compromised application can be used as a foothold for further attacks. The vulnerability also demonstrates the importance of proper input sanitization and object validation in document processing applications, which are frequently targeted due to their widespread use and the trust users place in document viewing software. Security professionals should consider implementing network-based intrusion detection systems and monitoring for suspicious document-related activity, as well as ensuring timely patch deployment to address this and similar vulnerabilities in document processing software.
Mitigation strategies should focus on immediate patching of affected Foxit Reader installations to the latest version that contains the necessary security fixes. Organizations should also implement network segmentation and access controls to limit the potential impact of successful exploitation attempts. Browser-based security measures including content filtering, sandboxing, and strict MIME type validation can help prevent users from accessing malicious content that could trigger this vulnerability. Additionally, security awareness training should emphasize the dangers of opening untrusted documents and visiting suspicious websites, as user interaction remains a required component for exploitation. System administrators should consider implementing application whitelisting policies to restrict execution of unauthorized software and monitor for unusual process behavior that might indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of secure coding practices, particularly around object validation and input sanitization, as these flaws can provide attackers with direct pathways to system compromise. Organizations should also conduct regular security assessments of their document processing applications to identify and remediate similar vulnerabilities that may exist in other software components.