CVE-2018-16291 in Foxit
Summary
by MITRE
An exploitable use-after-free vulnerability exists in the JavaScript engine of Foxit Reader before 9.3 and PhantomPDF before 9.3, a different vulnerability than CVE-2018-16292, CVE-2018-16293, CVE-2018-16294, CVE-2018-16295, CVE-2018-16296, and CVE-2018-16297. 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 • 07/31/2024
This vulnerability represents a critical use-after-free condition in the JavaScript engine of Foxit Reader and PhantomPDF products, affecting versions prior to 9.3. The flaw occurs when processing specially crafted PDF documents that cause the application to reuse memory previously freed by the JavaScript engine, creating a scenario where attacker-controlled data can be written to memory locations that were previously allocated for legitimate objects. This type of vulnerability falls under the CWE-416 category for use-after-free conditions, which are particularly dangerous because they can lead to arbitrary code execution when the freed memory is reallocated for malicious purposes. The vulnerability is distinct from several other related issues in the same product line, indicating a specific flaw in the memory management implementation within the JavaScript engine rather than a broader class of memory corruption problems.
The technical exploitation of this vulnerability requires an attacker to craft a malicious PDF document that triggers the JavaScript engine to perform operations on a previously freed object. When the JavaScript engine processes the malicious content, it may attempt to access or modify memory that was already released, leading to a situation where the freed memory can be overwritten with attacker-controlled data. This memory reuse allows for precise control over the execution flow, potentially enabling attackers to execute arbitrary code with the privileges of the victim user. The vulnerability is particularly concerning because it can be triggered through multiple attack vectors including opening malicious PDF files directly or visiting compromised websites when the browser plugin extension is enabled, making it a versatile threat that can be delivered through both file-based and web-based attack scenarios.
The operational impact of this vulnerability extends beyond simple code execution, as it can enable full system compromise when exploited successfully. Attackers can leverage the use-after-free condition to bypass modern security mitigations such as ASLR and DEP through techniques like return-oriented programming or just-in-time code generation. The vulnerability affects both desktop applications and browser plugins, increasing the attack surface significantly. Organizations using affected versions of Foxit Reader and PhantomPDF are exposed to potential exploitation through social engineering attacks, drive-by downloads, or targeted attacks where malicious PDF files are delivered via email or compromised websites. This vulnerability aligns with ATT&CK technique T1203 for Exploitation for Client Execution, where attackers leverage application vulnerabilities to execute code on victim systems.
Mitigation strategies should focus on immediate patching of affected versions to 9.3 or later, which addresses the underlying memory management issues in the JavaScript engine. Organizations should also implement strict file validation policies, disable the browser plugin extension if not required, and deploy web application firewalls to filter malicious PDF content. Security monitoring should include detection of unusual JavaScript engine behavior and memory access patterns that might indicate exploitation attempts. Additionally, user education regarding the dangers of opening untrusted PDF files and visiting suspicious websites remains crucial. The vulnerability highlights the importance of regular security updates and proper memory management practices in software development, particularly for applications that process untrusted content such as PDF documents. Organizations should also consider implementing sandboxing mechanisms and privilege separation to limit the potential impact of successful exploitation attempts.