CVE-2012-2983 in Webmin
Summary
by MITRE
file/edit_html.cgi in Webmin 1.590 and earlier does not perform an authorization check before showing a file s unedited contents, which allows remote attackers to read arbitrary files via the file field.
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Analysis
by VulDB Data Team • 04/22/2025
The vulnerability identified as CVE-2012-2983 represents a critical authorization bypass flaw in Webmin version 1.590 and earlier, specifically within the file/edit_html.cgi component. This issue stems from inadequate access control mechanisms that fail to verify user permissions before exposing file contents, creating a pathway for unauthorized information disclosure. The flaw exists in the web-based system administration interface that many organizations rely upon for managing their servers, making it particularly dangerous in enterprise environments where sensitive configuration files and system data are commonly stored.
The technical implementation of this vulnerability resides in the file/edit_html.cgi script which processes file editing requests without performing proper authentication checks. When an attacker submits a request containing a malicious file path in the file field parameter, the system retrieves and displays the contents of that file without verifying whether the requesting user possesses adequate privileges to access it. This represents a classic case of insufficient authorization control, where the system assumes that any legitimate request should be fulfilled regardless of user credentials or role-based access restrictions. The vulnerability essentially allows for arbitrary file reading capabilities, enabling attackers to access sensitive system files, configuration data, and potentially confidential information that should remain protected.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to gather intelligence about the target system, identify system configurations, and potentially discover credentials or other sensitive data stored in accessible files. Attackers could leverage this vulnerability to read system configuration files, log files, and other sensitive data that may contain passwords, encryption keys, or other valuable information for further exploitation. This flaw directly violates the principle of least privilege and can be classified under CWE-284, which addresses improper access control. The vulnerability also aligns with ATT&CK technique T1005, where adversaries collect data from local systems, and T1083, which involves discovering files and directories, making it a significant concern for defenders monitoring system integrity and access controls.
Mitigation strategies for CVE-2012-2983 primarily involve upgrading to Webmin version 1.591 or later, where the authorization check has been properly implemented. Organizations should also implement network segmentation to limit access to Webmin interfaces, deploy strong authentication mechanisms including multi-factor authentication, and regularly audit access logs for suspicious activities. Additional protective measures include configuring firewall rules to restrict access to Webmin ports, implementing intrusion detection systems to monitor for exploitation attempts, and conducting regular security assessments of web-based administration interfaces. The vulnerability demonstrates the critical importance of proper access control implementation in web applications and serves as a reminder of the need for comprehensive security testing, particularly around authentication and authorization mechanisms that protect sensitive system resources.