CVE-2006-3274 in Webmin
Summary
by MITRE
Directory traversal vulnerability in Webmin before 1.280, when run on Windows, allows remote attackers to read arbitrary files via \ (backslash) characters in the URL to certain directories under the web root, such as the image directory.
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Analysis
by VulDB Data Team • 03/13/2021
This vulnerability represents a classic directory traversal flaw that specifically affected Webmin versions prior to 1.280 when operating on Windows systems. The issue stems from inadequate input validation mechanisms within the web application's URL processing logic, allowing malicious actors to manipulate file paths through backslash character sequences. Attackers can exploit this weakness by crafting specially formatted URLs that target directories under the web root, particularly the image directory, enabling them to access files that should remain protected from remote retrieval.
The technical exploitation occurs when the web application fails to properly sanitize or validate user-supplied input containing backslash characters in the URL path. This allows attackers to traverse the file system hierarchy beyond the intended boundaries of the web root directory, potentially accessing sensitive configuration files, system files, or other restricted resources that should not be accessible through the web interface. The vulnerability specifically manifests on Windows systems due to differences in path handling between Windows and Unix-like operating systems, where backslash characters are interpreted differently in file system navigation.
From an operational impact perspective, this vulnerability creates significant security risks for systems running vulnerable Webmin versions, as it allows remote attackers to potentially access sensitive system information without authentication. The ability to read arbitrary files through the image directory access point could expose configuration files containing database credentials, encryption keys, or other sensitive data that could be leveraged for further attacks. This type of vulnerability directly violates the principle of least privilege and can enable attackers to escalate their access within the compromised system.
The vulnerability 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 attack framework perspective, this weakness maps to multiple ATT&CK techniques including T1083 (File and Directory Discovery) and T1566 (Phishing with Malicious Attachment) as attackers can use this vulnerability to discover and extract sensitive files from the target system. The attack chain typically involves initial reconnaissance to identify vulnerable Webmin installations followed by crafting malicious URLs to access restricted files.
Mitigation strategies for this vulnerability include immediate patching of Webmin to version 1.280 or later, which contains the necessary input validation fixes. Organizations should also implement network segmentation and access controls to limit exposure of Webmin interfaces to trusted networks only. Additionally, regular security auditing of web applications should include validation of input handling mechanisms, particularly for path-related operations. The implementation of web application firewalls and proper logging of file access attempts can provide additional layers of protection and detection capabilities for such attacks.