CVE-2001-0139 in INN
Summary
by MITRE
inn 2.2.3 allows local users to overwrite arbitrary files via a symlink attack in some configurations.
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Analysis
by VulDB Data Team • 10/08/2025
The vulnerability described in CVE-2001-0139 affects the inn software version 2.2.3, which represents a significant security flaw that enables local users to potentially overwrite arbitrary files through a carefully crafted symlink attack. This issue stems from improper handling of symbolic links within the software's file operations, creating a path traversal vulnerability that can be exploited by malicious users with local access to the system. The vulnerability is particularly concerning because it allows attackers to manipulate file system operations in ways that could compromise system integrity and potentially lead to privilege escalation or data corruption.
The technical flaw resides in the software's failure to properly validate or sanitize symbolic link references during file operations. When inn 2.2.3 processes files, it does not adequately check whether the target of a symbolic link points to a legitimate location or whether the link itself has been manipulated by an attacker. This oversight creates a window where a local user can create malicious symbolic links that, when processed by the vulnerable software, result in arbitrary file overwrites. The vulnerability is classified as a path traversal issue that aligns with CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
From an operational impact perspective, this vulnerability represents a serious threat to system security as it allows local users to potentially overwrite critical system files, configuration files, or user data. The attack vector is particularly dangerous because it requires only local access to the system, making it accessible to users who may not have elevated privileges. An attacker could leverage this vulnerability to overwrite system binaries, modify configuration files, or inject malicious code into the software's execution path, potentially leading to privilege escalation or persistent access to the compromised system. The attack's effectiveness is further amplified by the fact that it can be executed without requiring network access or special permissions beyond local system access.
The exploitation of this vulnerability typically involves creating a symbolic link that points to a target file the attacker wishes to overwrite, then triggering the vulnerable software to process this link in a way that causes the software to write data to the target file instead of the intended location. This type of attack is categorized under the attack techniques described in the MITRE ATT&CK framework, specifically relating to privilege escalation and persistence mechanisms. Organizations should implement immediate mitigations including updating to a patched version of inn software, implementing proper file system permissions, and conducting thorough security audits to identify and remove any existing symbolic links that could be exploited. Additionally, system administrators should monitor for unusual file modification patterns and ensure that local user access is properly controlled and monitored to prevent unauthorized manipulation of critical system files.