CVE-2025-67738: HIGH Severity Vulnerability | Secably CVE Database

Summary

CVE-2025-67738 is a high-severity vulnerability affecting Webmin versions prior to 2.600. It arises from improper argument quoting in the squid/cachemgr.cgi script, potentially allowing privilege escalation if specific conditions are met regarding Webmin's Squid module, Cache Manager feature, and user permissions.

An attacker with authenticated access to Webmin and certain Cache Manager permissions ('cms' security option) could exploit this vulnerability to execute arbitrary commands with elevated privileges.

Technical Details

The vulnerability stems from the squid/cachemgr.cgi script in Webmin not properly sanitizing or quoting arguments passed to underlying system commands. Specifically, when handling requests related to the Cache Manager feature within the Squid module, user-supplied input is incorporated into shell commands without adequate escaping.

This lack of proper quoting allows an attacker to inject malicious commands into the argument string. When the cachemgr.cgi script executes these commands, the injected code is executed with the privileges of the Webmin user, potentially leading to complete system compromise.

The 'cms' security option within Webmin's Squid module controls access to the Cache Manager feature. If an attacker has been granted this permission, they can manipulate the arguments passed to cachemgr.cgi and exploit the vulnerability.

Affected Products and Versions

Webmin versions prior to 2.600

Impact Assessment

Successful exploitation of CVE-2025-67738 can lead to a complete compromise of the Webmin server. An attacker could gain unauthorized access to sensitive data, modify system configurations, install malware, or use the compromised server as a launchpad for further attacks.

Data breach risk: Sensitive information stored on the Webmin server could be exposed.
System compromise: An attacker could gain complete control over the Webmin server.
Privilege Escalation: An attacker can escalate their privileges to root.

Remediation

Immediate Actions

Upgrade Webmin: Upgrade to Webmin version 2.600 or later to patch the vulnerability.
Review User Permissions: Carefully review and restrict access to the Cache Manager feature ('cms' security option) within Webmin's Squid module. Grant access only to trusted users who require it.
Monitor Webmin Logs: Monitor Webmin logs for suspicious activity, such as unusual commands being executed or unauthorized access attempts.

Long-term Solutions

Implement Input Validation: Ensure that all user-supplied input is properly validated and sanitized before being used in system commands.
Use Parameterized Queries: When interacting with databases, use parameterized queries to prevent SQL injection vulnerabilities.
Least Privilege Principle: Adhere to the principle of least privilege, granting users only the minimum necessary permissions to perform their tasks.

References

Detection & Scanning

This vulnerability can be detected by analyzing Webmin logs for suspicious activity related to the squid/cachemgr.cgi script. Specifically, look for unusual commands being executed or attempts to access the Cache Manager feature without proper authorization. Vulnerability scanners can also be used to identify vulnerable Webmin installations.

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