CVE-2018-20850 in Network Security
Summary
by MITRE
Stormshield Network Security 2.0.0 through 2.13.0 and 3.0.0 through 3.7.1 has self-XSS in the command line interface of the SNS web server.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 10/17/2023
The vulnerability identified as CVE-2018-20850 represents a critical self-cross-site scripting flaw within the Stormshield Network Security web interface. This issue affects versions 2.0.0 through 2.13.0 and 3.0.0 through 3.7.1 of the SNS platform, specifically within the command line interface of the web server component. The vulnerability stems from inadequate input validation and output encoding mechanisms that fail to properly sanitize user-supplied data before rendering it within the web interface context. This self-XSS vulnerability allows authenticated attackers with access to the command line interface to inject malicious scripts that execute in the context of the victim's browser session, potentially compromising the integrity of the administrative interface and enabling further exploitation.
The technical implementation of this vulnerability occurs when administrators interact with the command line interface of the Stormshield Network Security web server. The flaw manifests as the web server failing to properly escape or filter user input before displaying it in the web interface, creating a scenario where malicious payloads can be executed within the browser context of authenticated users. This self-XSS condition is particularly dangerous because it leverages the trust relationship between the user and the administrative interface, allowing attackers to execute code in the context of the victim's session with elevated privileges. The vulnerability directly maps to CWE-79 which defines Cross-Site Scripting as a weakness where untrusted data is sent to a web browser without proper validation or encoding, and aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter. The attack vector requires an authenticated session to the web interface, making it particularly concerning for environments where administrative access is limited but still exists.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to hijack administrative sessions, modify configuration settings, or escalate privileges within the network security infrastructure. An attacker could potentially use this vulnerability to inject malicious scripts that redirect users to phishing sites, steal session cookies, or manipulate the web interface to hide malicious activities. The self-XSS nature means that the vulnerability can be exploited by an attacker who already has access to the administrative interface, making it a particularly insidious threat for environments where administrative access is granted to multiple users. This vulnerability undermines the security posture of the entire Stormshield Network Security deployment, as it provides a vector for attackers to maintain persistence and conduct further reconnaissance or exploitation activities.
Mitigation strategies for CVE-2018-20850 should focus on immediate remediation through official patches provided by Stormshield, while also implementing additional security controls to reduce the attack surface. Organizations should enforce strict input validation and output encoding practices across all web interfaces, particularly for administrative components. The implementation of Content Security Policy headers can provide additional protection against XSS attacks by restricting script execution within the browser context. Network segmentation and privilege separation should be enforced to limit the potential impact of compromised administrative sessions. Regular security assessments and vulnerability scanning should include verification of proper input sanitization mechanisms. The vulnerability also highlights the importance of following secure coding practices and adhering to OWASP secure coding guidelines, particularly for web applications that handle privileged user input. Organizations should consider implementing web application firewalls and additional monitoring to detect and prevent exploitation attempts. The remediation process should include comprehensive testing to ensure that the patch does not introduce regressions in functionality while effectively addressing the XSS vulnerability in the command line interface component.