CVE-2017-16884 in MistServer
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in MistServer before 2.13 allows remote attackers to inject arbitrary web script or HTML via vectors related to failed authentication requests alerts.
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Analysis
by VulDB Data Team • 07/13/2025
The CVE-2017-16884 vulnerability represents a critical cross-site scripting flaw in MistServer versions prior to 2.13, specifically targeting the application's handling of failed authentication request alerts. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is classified as one of the most prevalent and dangerous web application security flaws in the CWE top 25 most dangerous software weaknesses. The vulnerability manifests when the system processes and displays error messages related to authentication failures without proper input sanitization or output encoding, creating an opportunity for malicious actors to inject arbitrary web scripts or HTML content into the application's response.
The technical exploitation of this vulnerability occurs through a carefully crafted authentication request that triggers an error response containing user-supplied input directly in the alert message. When MistServer processes failed authentication attempts, it fails to properly sanitize or encode the input parameters before including them in the error message display, allowing attackers to embed malicious scripts that execute in the context of other users' browsers. This type of vulnerability is particularly dangerous because it leverages the trust relationship between the web application and its users, enabling attackers to perform actions on behalf of authenticated users or steal sensitive information from their sessions.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with the capability to perform session hijacking, steal cookies, redirect users to malicious websites, or execute arbitrary commands within the victim's browser context. Attackers can craft malicious authentication requests that include script tags or other malicious payloads, which then get executed whenever legitimate users view the error messages. This vulnerability is particularly concerning in environments where MistServer handles sensitive user authentication data, as it could lead to unauthorized access to protected resources and potential data breaches. The vulnerability affects both authenticated and unauthenticated users who might encounter error messages during authentication attempts, making it a broad-spectrum threat that can be exploited through various attack vectors.
Mitigation strategies for CVE-2017-16884 should focus on implementing proper input validation and output encoding mechanisms throughout the application's authentication flow. Organizations should upgrade to MistServer version 2.13 or later, which includes the necessary patches to address this vulnerability. Additionally, implementing Content Security Policy headers, proper HTML encoding of all user-supplied input in error messages, and comprehensive input validation for authentication parameters can provide defense-in-depth measures. The vulnerability aligns with ATT&CK technique T1213 which covers credential access through the manipulation of authentication processes, and represents a classic example of how poor input handling can lead to severe security implications. Security teams should also consider implementing web application firewalls that can detect and block suspicious authentication request patterns, while maintaining regular security assessments to identify similar vulnerabilities in other components of the authentication infrastructure.