CVE-2011-4266 in FFFTP
Summary
by MITRE
Untrusted search path vulnerability in FFFTP before 1.98d allows local users to gain privileges via a Trojan horse executable file in a directory that is accessed for reading an extensionless file, as demonstrated by executing the README.exe file when a user attempts to access the README file, a different vulnerability than CVE-2011-3991.
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Analysis
by VulDB Data Team • 02/13/2019
The vulnerability described in CVE-2011-4266 represents a classic untrusted search path issue affecting FFFTP versions prior to 198d. This type of vulnerability falls under CWE-426 which specifically addresses the execution of untrusted code due to improper handling of search paths. The flaw occurs when an application fails to properly validate or sanitize the directories it searches for files, creating opportunities for attackers to place malicious executables in locations that the application will subsequently execute without proper verification.
The technical implementation of this vulnerability exploits the way FFFTP handles file access operations, particularly when dealing with extensionless files. When a user attempts to access a file such as README without an explicit file extension, the application searches through various directories in its configured search path. If the application does not properly verify the authenticity or source of files found in these directories, an attacker can place a malicious executable named README.exe in a directory that will be searched before the legitimate file location. This creates a privilege escalation scenario where local users can execute arbitrary code with the privileges of the target application.
The operational impact of this vulnerability is significant for systems running affected versions of FFFTP. Local attackers can leverage this weakness to execute malicious payloads without requiring elevated privileges, potentially leading to complete system compromise. The vulnerability specifically targets the application's file reading functionality and demonstrates how seemingly innocuous file access patterns can create security risks. Attackers can exploit this by placing malicious executables in directories that are commonly searched by the application, making the attack relatively straightforward to implement. The vulnerability is distinct from CVE-2011-3991, indicating it affects different aspects of the application's security model and requires separate mitigation approaches.
Mitigation strategies for CVE-2011-4266 should focus on implementing proper input validation and secure file handling practices. Organizations should immediately upgrade to FFFTP version 1.98d or later where this vulnerability has been addressed. Additionally, system administrators should review and restrict the directories that applications can access during file operations, implementing strict path validation to prevent execution of unauthorized binaries. The principle of least privilege should be applied to limit the directories that applications can search, and security monitoring should be enhanced to detect unauthorized file placements in application search paths. This vulnerability demonstrates the importance of secure coding practices and proper validation of file access operations, aligning with ATT&CK technique T1059.001 for execution through command and scripting interpreters, and T1548.001 for privilege escalation through abuse of system permissions.