CVE-2017-2265 in FileCapsule Deluxe Portable
Summary
by MITRE
Untrusted search path vulnerability in 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-2017-2265 represents a critical untrusted search path issue affecting FileCapsule Deluxe Portable version 1.0.4.1 and earlier. This type of vulnerability falls under the broader category of dynamic link library (dll) hijacking attacks and is classified as CWE-426 according to the Common Weakness Enumeration catalog. The flaw stems from the application's improper handling of dynamic library loading mechanisms, where the software fails to validate or properly secure the search paths used to locate required dll modules.
The technical implementation of this vulnerability exploits the Windows dynamic loading mechanism by placing a malicious dll file in a directory that is searched before the legitimate application directories. When FileCapsule Deluxe Portable executes, it attempts to load a required dll component but inadvertently loads the attacker-controlled malicious dll from a directory with higher precedence in the search order. This behavior creates an opportunity for privilege escalation as the malicious code executes with the same privileges as the legitimate application. The vulnerability is particularly concerning because it does not require elevated privileges to exploit, making it accessible to unauthenticated attackers.
From an operational perspective, this vulnerability presents significant risk to end-user systems as it allows attackers to execute arbitrary code within the context of the FileCapsule Deluxe Portable application. The attack vector relies on social engineering or pre-positioning of malicious files in directories that the application will traverse during normal operation. The impact extends beyond simple code execution to potential privilege escalation, as the malicious dll could be designed to perform actions such as creating backdoors, exfiltrating data, or establishing persistent access to the compromised system. This vulnerability aligns with techniques documented in the attack pattern taxonomy under the MITRE ATT&CK framework, specifically relating to privilege escalation and persistence mechanisms.
Mitigation strategies for this vulnerability should focus on implementing proper dll loading practices and addressing the underlying search path issues. Organizations should ensure that all applications implement secure dll loading by using absolute paths for dll resolution or by explicitly setting the search path to include only trusted directories. The recommended approach involves modifying the application's behavior to use LoadLibraryEx with the LOAD_WITH_ALTERED_SEARCH_PATH flag or by implementing proper path validation before dll loading operations. Additionally, system administrators should implement application whitelisting policies and monitor for suspicious dll loading activities. The vulnerability highlights the importance of following secure coding practices and adhering to the principle of least privilege in application design. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other applications that may be susceptible to similar search path manipulation attacks.