CVE-2017-2266 in FileCapsule Deluxe Portable
Summary
by MITRE
Untrusted search path vulnerability in Encrypted files in self-decryption format created by FileCapsule Deluxe Portable Ver.1.0.4.1 and earlier allows an attacker to gain privileges via a Trojan horse DLL in an unspecified directory.
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Analysis
by VulDB Data Team • 10/26/2019
The vulnerability identified as CVE-2017-2266 represents a critical untrusted search path weakness within FileCapsule Deluxe Portable version 1.0.4.1 and earlier implementations. This flaw specifically affects the self-decryption functionality of encrypted files created by the software, creating a pathway for privilege escalation attacks through malicious code injection. The vulnerability stems from the application's improper handling of dynamic link library loading sequences during the decryption process, where the software fails to validate the source and integrity of loaded modules.
This security weakness falls under the CWE-427 category of Untrusted Search Path, which is classified as a significant concern in software security practices. The vulnerability operates by leveraging the Windows dynamic loading mechanism where applications search for required libraries in a predetermined order including the current working directory. When FileCapsule Deluxe Portable processes encrypted files, it executes a self-decryption routine that loads necessary DLL components without properly validating their origins, creating an opportunity for attackers to place malicious DLLs in directories that are searched before system directories.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and data exfiltration. An attacker who gains write access to any directory that the application searches during decryption can place a malicious DLL with the same name as a legitimate dependency, causing the application to execute attacker-controlled code with the privileges of the user running the software. This creates a persistent threat vector where attackers can establish backdoors, steal credentials, or perform further exploitation within the compromised system.
The attack surface for this vulnerability is particularly concerning given the nature of file encryption software, which often operates with elevated privileges and handles sensitive data. The unspecified directory mentioned in the vulnerability description suggests that multiple potential attack vectors exist, including user home directories, temporary folders, or shared network locations that may be accessible to unprivileged users. This vulnerability directly maps to ATT&CK technique T1068 which covers the exploitation of local privileges through DLL injection and path manipulation attacks.
Mitigation strategies for CVE-2017-2266 should focus on implementing proper DLL loading practices and establishing secure search paths. Organizations should enforce the use of absolute paths for all dynamically loaded libraries, implement strict directory permissions, and utilize Windows security features such as AppLocker or Software Restriction Policies to prevent execution of unauthorized DLLs. Additionally, the affected software vendors should implement proper DLL verification mechanisms and ensure that all dynamically loaded components are properly signed and validated before execution. System administrators should conduct thorough security audits of all encryption software installations and implement monitoring for suspicious DLL loading activities. The vulnerability also underscores the importance of keeping encryption software updated and following secure coding practices that prevent untrusted search path exploitation patterns.