CVE-2018-18940 in Netscape
Summary
by MITRE
servlet/SnoopServlet (a servlet installed by default) in Netscape Enterprise 3.63 has reflected XSS via an arbitrary parameter=[XSS] in the query string. A remote unauthenticated attacker could potentially exploit this vulnerability to supply malicious HTML or JavaScript code to a vulnerable web application, which is then reflected back to the victim and executed by the web browser. NOTE: this product is discontinued.
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Analysis
by VulDB Data Team • 07/04/2023
The vulnerability identified as CVE-2018-18940 resides within the Netscape Enterprise Server 3.63 web application, specifically in the default-installed SnoopServlet component. This servlet serves as a diagnostic tool that provides information about the server's configuration and environment. The flaw manifests as a reflected cross-site scripting vulnerability that occurs when arbitrary parameters containing malicious code are passed through the query string of the URL. The vulnerability is classified under CWE-79 which specifically addresses Cross-Site Scripting flaws, where the application fails to properly sanitize user input before reflecting it back to the web browser.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious URL containing XSS payload within the parameter value and delivers it to unsuspecting users. When a victim accesses the crafted URL, the SnoopServlet processes the parameter and reflects the malicious content directly back in the HTTP response without proper input validation or output encoding. This creates a classic reflected XSS scenario where the malicious script executes within the victim's browser context, potentially allowing attackers to steal session cookies, perform unauthorized actions on behalf of users, or redirect victims to malicious websites. The vulnerability affects the web application's security model by undermining the trust boundary between the server and client, as the server becomes a conduit for executing arbitrary code in user browsers.
The operational impact of this vulnerability is significant despite the product being discontinued, as it represents a persistent security risk for organizations that may still be running legacy systems or have not fully migrated away from Netscape Enterprise Server. Attackers could leverage this vulnerability to perform session hijacking attacks, steal sensitive information from authenticated users, or deploy additional malicious payloads through browser-based attacks. The unauthenticated nature of the exploit means that no prior access or credentials are required to attempt the attack, making it particularly dangerous. This vulnerability aligns with ATT&CK technique T1566 which covers social engineering tactics involving the delivery of malicious content through web-based attacks.
Mitigation strategies for this vulnerability should focus on immediate remediation efforts including the complete removal or disabling of the SnoopServlet component from the web application, as well as implementing proper input validation and output encoding mechanisms. Organizations should ensure that all user-supplied input is properly sanitized before being reflected back to the browser, utilizing techniques such as HTML encoding, context-specific output escaping, and implementing Content Security Policy headers to limit script execution. Given the discontinued nature of Netscape Enterprise Server 3.63, the most effective long-term solution involves migrating to modern web application platforms that provide built-in protections against XSS vulnerabilities and receive regular security updates and patches. Additionally, network-level protections such as web application firewalls should be considered to provide an additional layer of defense against similar attacks.