CVE-2018-3961 in Foxit
Summary
by MITRE
A use-after-free vulnerability exists in the JavaScript engine of Foxit Software's Foxit PDF Reader version 9.1.0.5096. A use-after-free condition can occur when accessing the Creator property of the this.info object. An attacker needs to trick the user to open the malicious file to trigger this vulnerability. If the browser plugin extension is enabled, visiting a malicious site can also trigger the vulnerability.
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Analysis
by VulDB Data Team • 07/31/2024
The vulnerability identified as CVE-2018-3961 represents a critical use-after-free flaw within Foxit Software's PDF Reader application, specifically affecting version 9.1.0.5096. This type of vulnerability falls under the broader category of memory safety issues and is classified as CWE-416 according to the Common Weakness Enumeration framework. The flaw manifests in the JavaScript engine component of the PDF reader, which is commonly used for interactive document features and scripting capabilities. When processing PDF documents, the application fails to properly manage memory references, creating opportunities for malicious exploitation through improper memory access patterns.
The technical execution of this vulnerability occurs when the JavaScript engine attempts to access the Creator property of the this.info object within a PDF document. This particular access pattern creates a scenario where freed memory locations are still referenced, potentially allowing attackers to manipulate the application's memory state. The vulnerability requires user interaction to be exploited, either through opening a malicious PDF file or visiting a compromised website when the browser plugin extension is enabled. This user interaction requirement aligns with the ATT&CK technique T1203 - Exploitation for Client Execution, which describes how adversaries leverage application vulnerabilities to execute code on victim systems through user engagement with malicious content.
The operational impact of this vulnerability extends beyond simple code execution, as it can potentially allow attackers to achieve arbitrary code execution within the context of the PDF reader application. This represents a significant security risk since PDF readers often run with elevated privileges and have access to system resources. The vulnerability's exploitation can lead to complete system compromise, data exfiltration, or the installation of additional malware. The fact that the vulnerability can be triggered through web browsing activities when the browser plugin is enabled expands the attack surface significantly, making it more accessible to threat actors who may not need to rely on social engineering to deliver malicious PDF files directly.
Organizations and users should prioritize immediate remediation through updating to patched versions of Foxit PDF Reader, as the vulnerability represents a serious threat that can be exploited remotely. Security teams should implement network monitoring to detect potential exploitation attempts and consider disabling the browser plugin extension if it is not essential for business operations. The vulnerability demonstrates the importance of proper memory management in software applications and highlights the need for regular security assessments of commonly used applications, particularly those that process untrusted content. Additionally, implementing sandboxing mechanisms for PDF processing and employing multi-layered security controls can help mitigate the risk associated with such vulnerabilities in environments where the software cannot be immediately updated.