CVE-2011-3691 in Foxit
Summary
by MITRE
Untrusted search path vulnerability in Foxit Reader before 5.0.2.0718 allows local users to gain privileges via a Trojan horse dwmapi.dll, dwrite.dll, or msdrm.dll in the current working directory.
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Analysis
by VulDB Data Team • 11/20/2021
The vulnerability identified as CVE-2011-3691 represents a critical untrusted search path issue affecting Foxit Reader versions prior to 5.0.2.0718. This flaw resides in the application's dynamic link library loading mechanism, where the software fails to properly validate the source of dynamically loaded libraries. The vulnerability specifically targets three critical system libraries: dwmapi.dll, dwrite.dll, and msdrm.dll, which are legitimate Windows system components that are commonly found in the system PATH. When Foxit Reader executes, it searches for these libraries in the current working directory before checking the system directories, creating an opportunity for privilege escalation attacks.
The technical exploitation of this vulnerability occurs when a local attacker places a malicious version of one of these three DLL files in the same directory as the Foxit Reader executable or in the current working directory from which the application is launched. The application's improper search path implementation causes it to load the attacker-controlled DLL instead of the legitimate system version. This behavior directly maps to CWE-426 Untrusted Search Path, which specifically addresses the risk of applications loading executables or libraries from untrusted locations. The vulnerability demonstrates a classic privilege escalation vector where a local user can elevate their privileges to those of the target application, potentially gaining access to sensitive data or system resources.
The operational impact of this vulnerability extends beyond simple local privilege escalation, as it can be leveraged in various attack scenarios within enterprise environments. Attackers can combine this vulnerability with social engineering tactics to deliver malicious payloads through seemingly legitimate documents or files that trigger Foxit Reader execution. The attack requires minimal user interaction since the vulnerability is exploited during normal document viewing operations. According to ATT&CK framework, this vulnerability aligns with T1068 Privilege Escalation and T1546 Persistence, as it enables attackers to establish persistent access through the elevated privileges gained. The vulnerability affects all versions of Foxit Reader prior to 5.0.2.0718, making it particularly concerning for organizations that have not updated their document readers.
Mitigation strategies for this vulnerability primarily focus on patch management and system hardening. The most effective solution involves updating to Foxit Reader version 5.0.2.0718 or later, which implements proper DLL search path validation. Organizations should also implement application whitelisting policies to restrict the execution of unauthorized DLL files and establish secure coding practices that prioritize system directory searches over current working directory searches. Additionally, security awareness training should emphasize the risks of executing documents from untrusted sources, as the vulnerability can be exploited through malicious PDF files. Network segmentation and least privilege access controls can help minimize the impact if exploitation occurs, while regular security audits should verify that applications properly handle dynamic library loading. The vulnerability underscores the importance of following secure coding practices and demonstrates how seemingly minor implementation flaws can create significant security risks in widely deployed software applications.