CVE-2018-3992 in Foxit
Summary
by MITRE
An exploitable use-after-free vulnerability exists in the JavaScript engine of Foxit Software's Foxit PDF Reader, version 9.2.0.9297. 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.
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Analysis
by VulDB Data Team • 05/23/2023
The vulnerability identified as CVE-2018-3992 represents a critical use-after-free flaw within the JavaScript engine of Foxit PDF Reader version 9.2.0.9297, classified under CWE-416 as use of freed memory. This vulnerability resides in the browser plugin extension functionality of the software, creating a significant attack surface that can be exploited through multiple vectors including malicious PDF files and compromised websites. The flaw occurs when the JavaScript engine fails to properly manage memory references, allowing an attacker to manipulate freed memory objects and potentially execute arbitrary code with the privileges of the user running the vulnerable software.
The technical exploitation of this vulnerability requires careful crafting of PDF documents that can trigger specific memory management conditions within the Foxit PDF Reader's JavaScript engine. When processing malicious content, the engine performs operations that cause objects to be freed from memory while maintaining references to them. Subsequent access to these freed memory locations results in undefined behavior that attackers can manipulate to redirect execution flow. This particular implementation flaw demonstrates poor memory management practices where the JavaScript engine does not properly invalidate object references after deallocation, creating opportunities for attackers to overwrite freed memory with controlled data and subsequently execute malicious code.
The operational impact of CVE-2018-3992 extends beyond simple privilege escalation as it enables full system compromise when exploited successfully. The vulnerability can be triggered through user interaction with malicious PDF files or through web-based attacks when the browser plugin is enabled, making it particularly dangerous in enterprise environments where users frequently access untrusted websites. Attackers can leverage this vulnerability to install malware, steal sensitive data, or establish persistent access to compromised systems. The attack vector through browser plugins particularly increases the exploitability as users may inadvertently visit malicious websites without realizing the risk, making this vulnerability particularly effective in phishing campaigns and drive-by download attacks.
Mitigation strategies for CVE-2018-3992 should include immediate software updates from Foxit to patch the memory management flaws in the JavaScript engine. Organizations should implement strict content filtering policies and disable browser plugin extensions when possible to reduce attack surface. Security teams should monitor for exploitation attempts through network traffic analysis and endpoint detection systems. The vulnerability aligns with ATT&CK technique T1203 (Exploitation for Client Execution) and T1059.007 (Command and Scripting Interpreter: JavaScript) as it leverages browser-based execution and JavaScript engine exploitation. Additionally, implementing application whitelisting policies and user education about suspicious PDF files can provide additional defense layers. Regular security assessments of PDF processing capabilities and browser plugin configurations should be conducted to identify similar memory management vulnerabilities in other software components.
The vulnerability demonstrates the importance of proper memory management in complex software applications and highlights the risks associated with JavaScript engines in PDF readers. This flaw serves as a reminder of the critical need for thorough security testing of memory management operations and proper validation of object lifecycles in software applications. Organizations should prioritize patch management processes and maintain awareness of similar vulnerabilities in other PDF processing software to ensure comprehensive protection against memory corruption attacks.