CVE-2011-3991 in FFFTP
Summary
by MITRE
Untrusted search path vulnerability in FFFTP 1.98a and earlier allows local users to execute arbitrary code via unspecified functions.
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Analysis
by VulDB Data Team • 02/13/2019
The vulnerability identified as CVE-2011-3991 represents a critical untrusted search path issue affecting FFFTP version 1.98a and earlier. This type of vulnerability falls under the broader category of path traversal and dynamic link library injection flaws that have been consistently categorized by CWE-426 as "Untrusted Search Path" or "Path Traversal" vulnerabilities. The flaw exists within the file transfer protocol client software that is commonly used for ftp operations on windows systems.
The technical implementation of this vulnerability stems from improper handling of system search paths during the execution of file operations. When FFFTP processes certain file operations or loads dynamic libraries, it fails to properly validate or sanitize the search paths used to locate required components. This allows a local attacker to manipulate the system's library loading sequence by placing malicious executables or DLL files in directories that are searched before the legitimate system directories. The vulnerability specifically affects unspecified functions within the application, suggesting that multiple code paths may be susceptible to this type of manipulation.
From an operational impact perspective, this vulnerability creates a significant risk for local users who can leverage it to execute arbitrary code with the privileges of the FFFTP process. The attack vector requires local system access, which means that the vulnerability cannot be exploited remotely, but it does represent a privilege escalation risk for users who already have access to the system. This type of vulnerability is particularly dangerous in environments where multiple users share systems or where FFFTP is run with elevated privileges. The potential for privilege escalation through DLL injection or executable replacement attacks aligns with techniques documented in the MITRE ATT&CK framework under T1059 for command and scripting interpreter and T1546 for exploitation for persistence.
The exploitation of this vulnerability typically involves creating malicious files in directories that FFFTP searches before legitimate system locations, allowing attackers to inject code that will be executed when the application performs file operations. This attack pattern is consistent with common privilege escalation techniques where attackers manipulate the execution environment to achieve unauthorized code execution. Security professionals should note that this vulnerability represents a classic example of poor input validation and insecure library loading practices that have been addressed through various mitigation strategies including proper path validation, use of absolute paths, and implementation of secure coding practices. Organizations should prioritize updating FFFTP to versions that address this vulnerability, as well as implementing monitoring for suspicious file creation patterns in system directories.