CVE-2018-3965 in Foxit
Summary
by MITRE
An exploitable use-after-free vulnerability exists in the JavaScript engine of Foxit Software's Foxit PDF Reader version 9.1.0.5096. A specially crafted PDF document can trigger a previously freed object in memory to be reused, resulting in arbitrary code execution. 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.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 03/29/2020
The vulnerability identified as CVE-2018-3965 represents a critical use-after-free flaw within the JavaScript engine of Foxit PDF Reader version 9.1.0.5096, classified under CWE-416 as use of freed memory. This vulnerability exposes the application to potential arbitrary code execution scenarios where an attacker can manipulate the memory state of the running process. The flaw specifically manifests when processing specially crafted PDF documents that contain malicious JavaScript code designed to exploit the memory management error. The vulnerability operates through a sophisticated memory corruption mechanism that allows attackers to reuse previously freed memory objects, creating a pathway for code injection and system compromise. This type of vulnerability is particularly dangerous because it can be triggered through multiple attack vectors including direct file execution and web-based exploitation when the browser plugin extension is enabled.
The technical exploitation of this vulnerability relies on the JavaScript engine's improper handling of memory allocation and deallocation processes within the PDF rendering environment. When a malicious PDF document is processed, the engine allocates memory for JavaScript objects and subsequently frees them during normal execution flow. However, the flawed implementation allows for subsequent access to these freed memory regions, enabling attackers to manipulate the memory contents and redirect execution flow. The attack requires careful crafting of PDF content that includes JavaScript code capable of triggering the specific memory corruption pattern. The vulnerability is particularly concerning because it operates at the core rendering engine level, where memory management errors can have cascading effects on the entire application security posture. This flaw demonstrates a fundamental weakness in the memory management subsystem that affects the integrity of the application's execution environment.
The operational impact of CVE-2018-3965 extends beyond simple code execution to encompass complete system compromise potential when exploited successfully. Attackers can leverage this vulnerability to gain unauthorized access to user systems, execute malicious payloads, and potentially escalate privileges depending on the execution context. The vulnerability's exploitation requires user interaction through opening malicious files or visiting compromised websites, making it a prime candidate for social engineering attacks. The browser plugin extension component adds another attack surface that can be exploited through web-based delivery methods, expanding the attack vectors significantly. Organizations using Foxit PDF Reader are particularly vulnerable as this flaw affects the widely deployed PDF viewing application, potentially exposing thousands of endpoints to exploitation. The vulnerability's severity is further amplified by the fact that it can be triggered through multiple delivery mechanisms, increasing the probability of successful exploitation.
Mitigation strategies for CVE-2018-3965 should focus on immediate patch management and operational security enhancements. The most effective solution involves applying the vendor-provided security update that addresses the memory management flaw in the JavaScript engine. Organizations should implement strict file access controls and user education programs to prevent opening suspicious PDF documents. Network-based defenses including web application firewalls and content filtering systems can help block malicious PDF content before it reaches end users. Security teams should monitor for exploitation attempts through network traffic analysis and endpoint detection systems that can identify anomalous JavaScript execution patterns. Additionally, disabling the browser plugin extension when not required can reduce the attack surface, though this may impact functionality. The vulnerability highlights the importance of regular security assessments and maintaining updated software versions to protect against known memory corruption flaws. Organizations should also consider implementing sandboxing mechanisms and privilege separation to limit the impact of successful exploitation attempts. The ATT&CK framework categorizes this vulnerability under the T1059.007 technique for JavaScript-based execution, emphasizing the need for comprehensive endpoint protection strategies.