CVE-2017-9313 in Webmin
Summary
by MITRE
Multiple Cross-site scripting (XSS) vulnerabilities in Webmin before 1.850 allow remote attackers to inject arbitrary web script or HTML via the sec parameter to view_man.cgi, the referers parameter to change_referers.cgi, or the name parameter to save_user.cgi. NOTE: these issues were not fixed in 1.840.
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Analysis
by VulDB Data Team • 12/09/2022
The vulnerability CVE-2017-9313 represents a critical cross-site scripting flaw affecting Webmin versions prior to 1.850, specifically targeting three distinct CGI scripts that handle user input without proper sanitization. This vulnerability falls under CWE-79 which defines cross-site scripting as a weakness where untrusted data is embedded into web pages viewed by other users, creating potential for malicious code execution. The affected parameters include the sec parameter in view_man.cgi, the referers parameter in change_referers.cgi, and the name parameter in save_user.cgi, all of which accept user-supplied data that can be manipulated to inject malicious scripts.
The technical exploitation of this vulnerability occurs through the manipulation of CGI parameters that are processed by Webmin's administrative interface without adequate input validation or output encoding. When an attacker crafts malicious payloads and injects them through these specific parameters, the vulnerable Webmin instances execute the injected scripts within the context of other users' browsers. This allows attackers to perform actions such as stealing session cookies, redirecting users to malicious sites, or executing arbitrary commands on behalf of authenticated users. The vulnerability is particularly dangerous because it affects core administrative functions that are frequently accessed by system administrators, creating a high-impact attack surface.
The operational impact of CVE-2017-9313 extends beyond simple script injection, as it enables attackers to escalate privileges and gain unauthorized access to administrative functions within the Webmin interface. According to ATT&CK framework technique T1059.007, this vulnerability facilitates code injection through web applications, while T1566.001 addresses the initial access vector through malicious web content. The fact that these issues were not addressed in version 1.840 indicates a prolonged window of exposure, allowing attackers to exploit the vulnerability for extended periods. System administrators who rely on Webmin for server management face significant risk of compromise, as successful exploitation can lead to complete system takeover and persistent backdoor access.
Mitigation strategies for CVE-2017-9313 require immediate implementation of version upgrades to Webmin 1.850 or later, as this represents the official fix for the identified XSS vulnerabilities. Organizations should also implement proper input validation and output encoding mechanisms at multiple layers, including web application firewalls and server-side sanitization routines. Network segmentation and privileged access controls can help limit the impact if exploitation occurs, while regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other web applications. Additionally, implementing content security policies and disabling unnecessary administrative functions can reduce the attack surface and prevent successful exploitation attempts. The vulnerability demonstrates the critical importance of timely patch management and proper input sanitization in web application security.