CVE-2000-0935 in Samba
Summary
by MITRE
Samba Web Administration Tool (SWAT) in Samba 2.0.7 allows local users to overwrite arbitrary files via a symlink attack on the cgi.log file.
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Analysis
by VulDB Data Team • 12/07/2024
The vulnerability identified as CVE-2000-0935 resides within the Samba Web Administration Tool (SWAT) component of Samba version 2.0.7, representing a critical security flaw that enables local attackers to manipulate file system permissions and potentially execute unauthorized operations. This issue specifically targets the handling of log file operations within the web administration interface, creating an avenue for privilege escalation and data corruption. The vulnerability demonstrates a fundamental flaw in how the system manages file creation and access control during web-based administrative tasks, particularly when dealing with symbolic link exploitation techniques that bypass normal file system protections.
The technical implementation of this vulnerability stems from improper handling of file creation operations within the SWAT interface, where the application fails to properly validate or sanitize file paths when writing to the cgi.log file. Attackers can exploit this weakness by creating a symbolic link with a carefully crafted name that points to a target file of their choice, then triggering the log writing process through the web interface. When the system attempts to write to the log file, it follows the symbolic link and writes data to the target file instead of the intended log location. This type of attack falls under the category of symlink-based file manipulation attacks, which are categorized under CWE-59 and specifically relate to improper handling of symbolic links in file operations. The vulnerability directly impacts the integrity and confidentiality of system files, as malicious users can overwrite critical system files, configuration data, or sensitive log information with arbitrary content.
The operational impact of CVE-2000-0935 extends beyond simple file overwriting, as it provides attackers with a mechanism to compromise the entire Samba service and potentially gain elevated privileges on the affected system. Local users who can access the SWAT interface can leverage this vulnerability to modify system files, inject malicious code, or corrupt critical operational data, leading to potential service disruption, data loss, or complete system compromise. The attack vector is particularly dangerous because it requires minimal privileges and can be executed through standard web browser interactions with the SWAT interface. This vulnerability aligns with ATT&CK technique T1059.007 for execution through web shells and T1490 for data destruction, as it enables attackers to manipulate system files and potentially cause service interruptions. The impact is amplified in environments where SWAT is configured with default settings or where local user access is not properly restricted, making the attack surface larger and more accessible to potential adversaries.
Mitigation strategies for this vulnerability must address both the immediate security flaw and broader system hardening practices. The most effective immediate solution involves applying the official security patch released by the Samba development team, which corrects the file handling logic and implements proper validation of file paths before log operations. System administrators should also implement strict access controls on the SWAT interface, ensuring that only authorized personnel can access the web administration tools, and that the interface is properly secured behind firewalls or authentication mechanisms. Additionally, monitoring for suspicious file system activities and log file modifications should be implemented to detect potential exploitation attempts. The vulnerability highlights the importance of proper input validation and file system security practices, particularly in web-based administrative interfaces. Organizations should also consider implementing automated security scanning tools to identify similar weaknesses in other applications and systems, as this type of symlink attack is a common pattern that affects many web applications. Regular security audits and penetration testing should be conducted to ensure that such vulnerabilities are identified and remediated before they can be exploited by malicious actors.