CVE-2012-0315 in ALFTP
Summary
by MITRE
Untrusted search path vulnerability in ALFTP before 5.31 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.
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Analysis
by VulDB Data Team • 11/30/2021
The vulnerability described in CVE-2012-0315 represents a classic untrusted search path issue affecting ALFTP software versions prior to 5.31. This flaw manifests when the application processes extensionless files, creating an opportunity for local attackers to execute malicious code through carefully placed Trojan horse executables. The vulnerability specifically exploits the application's handling of file access operations where it searches through multiple directories without proper validation of the file origins, leading to potential privilege escalation.
The technical implementation of this vulnerability involves the application's failure to properly validate file paths when processing extensionless files. When a user attempts to access a file such as README without an extension, the application searches through a predefined list of directories for any file matching that name. If an attacker places a malicious executable named README.exe in a directory that gets searched before the legitimate file location, the application will execute the malicious file instead of the intended extensionless file. This behavior directly violates the principle of least privilege and demonstrates a fundamental flaw in input validation and file resolution mechanisms.
From an operational impact perspective, this vulnerability enables local privilege escalation attacks where attackers can execute arbitrary code with the privileges of the target user. The attack vector is particularly concerning because it requires minimal user interaction beyond attempting to access a simple file, making it difficult to detect and prevent. The vulnerability affects any local user who has access to the affected system and can manipulate the file system to place malicious executables in directories that the application searches. This creates a persistent threat that can be exploited repeatedly without requiring additional authentication or network access.
The attack pattern aligns with several established threat methodologies including the use of Trojan horses and privilege escalation techniques. According to the ATT&CK framework, this vulnerability could be leveraged under the privilege escalation tactic, specifically using techniques such as trusted developer utilities and legitimate credentials. The vulnerability also maps to CWE-427 Uncontrolled Search Path Element, which describes how applications that search for files in a list of directories without proper validation can be exploited by placing malicious files in those directories. The flaw demonstrates poor security practices in path resolution and highlights the importance of proper file validation and secure coding practices.
Mitigation strategies for this vulnerability should focus on implementing secure file path resolution practices and restricting the directories that applications search for file operations. System administrators should ensure that ALFTP is updated to version 5.31 or later, which contains the necessary patches to address the untrusted search path issue. Additional protective measures include implementing proper file permissions, restricting write access to directories that applications search, and conducting regular security audits of file system access patterns. Organizations should also consider implementing application whitelisting policies and monitoring for suspicious file access patterns to detect potential exploitation attempts. The vulnerability serves as a reminder of the critical importance of secure coding practices and proper input validation in preventing privilege escalation attacks.