CVE-2019-8334 in SchoolCMS
Summary
by MITRE
An issue was discovered in SchoolCMS 2.3.1. There is an XSS vulnerability via index.php?a=Index&c=Channel&m=Home&viewid=[XSS].
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Analysis
by VulDB Data Team • 07/10/2023
The vulnerability identified as CVE-2019-8334 affects SchoolCMS version 2.3.1 and represents a cross-site scripting flaw that could enable attackers to execute malicious scripts in the context of a victim's browser. This issue manifests through the index.php endpoint with specific query parameters including a=Index&c=Channel&m=Home&viewid=[XSS], indicating that the application fails to properly sanitize user input when processing the viewid parameter. The vulnerability resides within the web application's input validation mechanisms, creating an opportunity for attackers to inject malicious code that persists in the application's output.
The technical flaw stems from insufficient output encoding and input validation within the SchoolCMS framework, specifically in how it handles the viewid parameter within the Channel controller's Home method. When the application processes this parameter without proper sanitization or encoding, it allows malicious payloads to be executed in the browser context of authenticated users who view the affected content. This represents a classic reflected cross-site scripting vulnerability where the malicious script is reflected off the web server and executed in the victim's browser, potentially leading to session hijacking, credential theft, or redirection to malicious sites. The vulnerability aligns with CWE-79 which defines cross-site scripting as a weakness where applications fail to properly validate or encode user-controllable data before including it in output that is sent to web browsers.
The operational impact of this vulnerability extends beyond simple script execution as it can facilitate more sophisticated attacks within the application's context. An attacker could leverage this vulnerability to steal session cookies, potentially gaining unauthorized access to user accounts with elevated privileges. The vulnerability affects the application's integrity and confidentiality by allowing unauthorized code execution in user browsers, which could lead to data exfiltration or further exploitation of the system. Given that SchoolCMS is typically used in educational environments, this vulnerability could compromise student and staff data, potentially leading to privacy violations and regulatory compliance issues.
Mitigation strategies for CVE-2019-8334 should focus on implementing proper input validation and output encoding mechanisms throughout the application. The most effective approach involves sanitizing all user inputs, particularly parameters like viewid, through proper encoding before they are processed or displayed in the application's output. This includes implementing context-specific encoding such as HTML entity encoding for content rendered in web pages. Additionally, the application should employ Content Security Policy (CSP) headers to prevent unauthorized script execution and implement proper parameter validation using allow-lists for acceptable input values. The vulnerability also maps to ATT&CK technique T1203 which involves exploiting web applications to gain access to user sessions, highlighting the need for comprehensive web application security controls. Organizations should also consider implementing web application firewalls and regular security testing to identify similar vulnerabilities in other components of the SchoolCMS system or related applications.