CVE-2018-3958 in Foxit
Summary
by MITRE
A use-after-free vulnerability exists in the JavaScript engine of Foxit Software's Foxit PDF Reader version 9.1.0.5096. A use-after-free condition can occur when accessing the Subject property of the this.info object. 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 • 07/30/2024
The vulnerability CVE-2018-3958 represents a critical use-after-free flaw within Foxit Software's PDF Reader application, specifically affecting version 9.1.0.5096. This issue resides in the JavaScript engine component that processes PDF documents containing embedded scripts. The vulnerability manifests when the application attempts to access the Subject property of the this.info object within a PDF's JavaScript context, creating a scenario where memory previously allocated to an object is accessed after that memory has been freed. This fundamental memory management error creates a dangerous condition that can be exploited by malicious actors to execute arbitrary code on affected systems.
The technical exploitation of this vulnerability follows a well-established pattern that aligns with CWE-416, which specifically addresses use-after-free conditions in software implementations. When a PDF document is processed, the JavaScript engine initializes an object containing document information including the Subject property. Under normal circumstances, this object maintains valid memory references throughout its lifecycle. However, in the vulnerable implementation, a race condition or improper memory management allows the object's memory to be freed while still referenced by subsequent JavaScript operations. The attacker must first convince the user to open a specially crafted malicious PDF file, which contains JavaScript code designed to trigger the memory corruption. This user interaction requirement places the vulnerability in the category of client-side attacks that rely on social engineering techniques to achieve successful exploitation.
The operational impact of CVE-2018-3958 extends beyond simple code execution, potentially enabling full system compromise through the ATT&CK framework's technique T1059.007, which covers scripting languages. Once successfully exploited, attackers can leverage this vulnerability to gain arbitrary code execution privileges, potentially leading to complete system compromise, data exfiltration, or deployment of additional malware. The vulnerability's trigger mechanism through browser plugin extensions creates an additional attack surface that aligns with ATT&CK technique T1203, where adversaries use malicious websites to deliver payloads. This dual exploitation vector increases the attack surface and makes the vulnerability particularly dangerous in enterprise environments where users frequently interact with web content and PDF documents.
Mitigation strategies for this vulnerability should address both the immediate security risk and the underlying memory management issues. Organizations should prioritize immediate patching of Foxit PDF Reader to versions that have addressed this specific use-after-free condition, following the remediation guidance provided by Foxit Software and security vendors. Additionally, implementing content filtering solutions that scan PDF documents for malicious JavaScript patterns can provide defense-in-depth protection. Network administrators should consider disabling the browser plugin extension for Foxit PDF Reader when it's not actively required, as this reduces the attack surface by eliminating the web-based exploitation vector. Security monitoring should include detection of suspicious PDF file access patterns and JavaScript execution behaviors that may indicate exploitation attempts, while also maintaining regular vulnerability assessments to identify similar memory corruption issues in other PDF processing software components.