CVE-2018-3842 in Foxit
Summary
by MITRE
An exploitable use of an uninitialized pointer vulnerability exists in the JavaScript engine in Foxit PDF Reader version 9.0.1.1049. A specially crafted PDF document can lead to a dereference of an uninitialized pointer which, if under attacker control, can result in arbitrary code execution. An attacker needs to trick the user to open a 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 • 03/03/2023
The vulnerability identified as CVE-2018-3842 represents a critical security flaw in Foxit PDF Reader version 9.0.1.1049 within its JavaScript engine implementation. This issue manifests as an uninitialized pointer dereference that can be exploited to achieve arbitrary code execution on affected systems. The vulnerability resides in the way the JavaScript engine processes PDF documents, specifically when handling certain malformed or crafted PDF files that contain malicious JavaScript code. The flaw demonstrates characteristics consistent with CWE-476 which describes NULL pointer dereferences, though in this case the pointer is uninitialized rather than explicitly null, creating a similar exploitable condition where memory access occurs without proper initialization.
The technical exploitation of this vulnerability requires a user to interact with a maliciously crafted PDF document or webpage containing embedded malicious JavaScript code. When the PDF reader processes such content, the uninitialized pointer causes unpredictable behavior during memory access operations. This condition allows attackers to potentially control program execution flow through memory corruption techniques, enabling them to execute arbitrary code with the privileges of the victim user. The attack vector is particularly concerning because it can be delivered through multiple channels including direct file attachment or web-based delivery when the browser plugin extension is enabled, expanding the potential attack surface significantly.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise when successfully exploited. An attacker who successfully exploits this vulnerability can gain full control over the victim's system, potentially leading to data exfiltration, persistence mechanisms installation, or further network reconnaissance activities. The vulnerability affects the core functionality of the PDF reader application and demonstrates a fundamental flaw in input validation and memory management within the JavaScript engine component. This type of vulnerability aligns with ATT&CK technique T1059.007 which covers JavaScript and VBScript execution, and T1203 which covers Exploitation for Client Execution, representing a classic client-side exploitation scenario that leverages user interaction for successful compromise.
Mitigation strategies for CVE-2018-3842 should prioritize immediate patching of the Foxit PDF Reader application to the latest available version that addresses this specific vulnerability. Organizations should implement strict file validation policies that prevent execution of potentially malicious PDF files from untrusted sources. Security teams should consider disabling JavaScript execution within PDF readers as an additional defensive measure, though this may impact legitimate document functionality. Network-based defenses such as web application firewalls and content filtering solutions can help detect and block malicious PDF content before it reaches end users. Regular security assessments should include verification that all PDF reader installations are patched and that appropriate security configurations are in place. The vulnerability also underscores the importance of keeping all software components updated and maintaining robust security monitoring to detect potential exploitation attempts.