CVE-2019-5145 in Foxit
Summary
by MITRE
An exploitable use-after-free vulnerability exists in the JavaScript engine of Foxit PDF Reader, version 9.7.0.29435. 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 • 03/24/2024
The vulnerability identified as CVE-2019-5145 represents a critical use-after-free flaw within the JavaScript engine of Foxit PDF Reader version 9.7.0.29435. This type of vulnerability falls under the common weakness enumeration CWE-416 which specifically addresses the use of freed memory conditions. The flaw manifests when a maliciously crafted PDF document is processed by the vulnerable software, creating a scenario where previously deallocated memory objects are accessed and reused, potentially leading to arbitrary code execution. The vulnerability exists at the intersection of memory management and script execution within the PDF rendering engine, making it particularly dangerous as it can be triggered through standard PDF document processing activities.
The technical exploitation of this vulnerability occurs through the JavaScript engine's handling of memory allocation and deallocation processes. When the PDF reader processes a specially crafted document, it executes JavaScript code that inadvertently causes a memory object to be freed from the heap while references to it remain in the system. Subsequently, when the application attempts to access this freed memory location, it can be overwritten with attacker-controlled data, leading to a situation where the program continues execution with malicious instructions in memory. This particular flaw demonstrates the classic use-after-free pattern where the timing and memory management sequence creates an exploitable condition that can be leveraged for privilege escalation or complete system compromise.
The operational impact of CVE-2019-5145 extends beyond simple code execution to encompass potential full system compromise when exploited successfully. The vulnerability requires user interaction through opening a malicious PDF file or visiting a malicious website when browser plugin extensions are enabled, making it particularly dangerous in phishing scenarios or when users browse untrusted websites. Attackers can leverage this vulnerability to execute arbitrary code with the privileges of the victim user, potentially leading to data theft, system reconnaissance, or establishment of persistent backdoors. The attack surface is particularly broad given that PDF readers are commonly installed across enterprise environments and personal computing devices, making this vulnerability particularly attractive to threat actors.
Mitigation strategies for CVE-2019-5145 should prioritize immediate patching of the affected Foxit PDF Reader version 9.7.0.29435 to address the underlying memory management flaw. Organizations should implement defensive measures including email filtering to prevent malicious PDF attachments, web application firewalls to detect and block malicious content, and user education to avoid opening suspicious PDF files. The vulnerability aligns with ATT&CK technique T1203 which covers exploitation of remote services, and T1059 which covers execution through scripting. Network segmentation and application whitelisting can provide additional layers of protection, while monitoring for unusual PDF processing activities or memory access patterns can help detect potential exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify similar memory corruption issues in other PDF rendering engines and browser components.