CVE-2018-16294 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-2018-16291, CVE-2018-16292, CVE-2018-16293, 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 applications, affecting versions prior to 9.3. The flaw occurs when processing specially crafted PDF documents that manipulate memory allocation patterns within the JavaScript interpreter. The vulnerability specifically targets the improper handling of object lifecycles where memory previously allocated to an object is freed but subsequently accessed or reallocated, creating a scenario where an attacker can control the memory layout to execute arbitrary code. This type of vulnerability falls under the CWE-416 category for use-after-free conditions and aligns with the ATT&CK technique T1059.007 for JavaScript-based execution.
The technical exploitation mechanism relies on the ability to manipulate the JavaScript engine's garbage collection behavior and memory management routines. When a malicious PDF document is processed, it triggers a sequence where an object reference is maintained beyond its intended lifetime, allowing the attacker to overwrite the freed memory with controlled data. The attacker can then leverage this condition to redirect execution flow, typically through return-oriented programming or jump-oriented programming techniques, effectively taking control of the application's execution context. The vulnerability's impact is amplified when the browser plugin extension is enabled, as it allows remote exploitation through web-based attacks rather than requiring local user interaction.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete system compromise, as the JavaScript engine in PDF readers typically operates with the privileges of the user who opened the document. Attackers can leverage this to execute malicious payloads, establish persistent backdoors, or escalate privileges to system-level access. The vulnerability's exploitation requires social engineering to convince users to open malicious PDF files, but the browser plugin extension enables more sophisticated attack vectors including drive-by downloads and cross-site scripting scenarios. This vulnerability demonstrates the inherent risks of complex JavaScript engines embedded within document processing applications, where the interaction between memory management and script execution can create dangerous conditions for attackers. Organizations using these applications should prioritize immediate patching, implement strict document filtering policies, and consider sandboxing mechanisms to limit potential damage from such exploits. The vulnerability also highlights the importance of maintaining up-to-date security patches and implementing network-based protections to prevent exploitation through web-based attack vectors.