CVE-2020-18467 in BigTree
Summary
by MITRE • 08/27/2021
Cross Site Scripting (XSS) vulnerabilty exists in BigTree-CMS 4.4.3 in the tag name field found in the Tags page under the General menu via a crafted website name by doing an authenticated POST HTTP request to admin/tags/create.
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Analysis
by VulDB Data Team • 09/01/2021
This cross site scripting vulnerability in BigTree CMS 4.4.3 represents a critical security flaw that allows authenticated attackers to inject malicious scripts into the application's tag management system. The vulnerability specifically affects the tag name field within the Tags page accessible through the General menu, making it a server-side input validation issue that can be exploited by users with valid credentials. The attack vector requires an authenticated POST HTTP request to the admin/tags/create endpoint, which means that an attacker must first obtain legitimate user credentials or exploit a separate authentication bypass to reach this vulnerable functionality.
The technical implementation of this vulnerability stems from insufficient sanitization of user input in the tag name field, which fails to properly filter or escape special characters that could be interpreted as executable script code by web browsers. When a crafted malicious payload is submitted through the tag creation form, the application stores this unvalidated input without proper encoding, allowing the malicious script to execute in the context of other users' browsers who view the affected tag listings. This classic XSS flaw operates under CWE-79 which categorizes improper neutralization of input during web page generation as a fundamental web application security weakness.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform session hijacking, steal sensitive user data, redirect victims to malicious sites, or even execute administrative actions if the victim is an administrator. The authenticated nature of the attack means that the exploitation requires legitimate user access, but this access can be obtained through credential theft, social engineering, or other initial compromise techniques. The vulnerability affects the core content management functionality and could potentially allow attackers to escalate privileges or gain unauthorized access to sensitive administrative features. According to ATT&CK framework, this represents a privilege escalation technique through web application vulnerabilities that can be leveraged for persistent access and data exfiltration.
Organizations using BigTree CMS 4.4.3 should implement immediate mitigations including input validation and output encoding for all user-supplied data in the tag management system, proper sanitization of special characters, and implementation of Content Security Policy headers to limit script execution. The recommended solution involves upgrading to a patched version of BigTree CMS where input validation has been strengthened and all user inputs are properly escaped before being stored or displayed in web pages. Additionally, administrators should consider implementing web application firewalls to detect and block suspicious POST requests to the vulnerable endpoint, and conduct regular security assessments to identify similar input validation flaws in other parts of the application.