Source: cve@mitre.org
NetBox through 2.6.2 allows an Authenticated User to conduct an XSS attack against an admin via a GFM-rendered field, as demonstrated by /dcim/sites/add/ comments.
NetBox versions up to 2.6.2 are vulnerable to a Cross-Site Scripting (XSS) attack, allowing an authenticated user to inject malicious JavaScript code into the application. This vulnerability enables attackers to potentially steal user credentials, redirect users to malicious websites, or compromise the integrity of the NetBox instance, impacting data center infrastructure management.
Step 1: Authentication: The attacker authenticates to the NetBox instance with valid credentials.
Step 2: Payload Injection: The attacker crafts a malicious payload containing JavaScript code (e.g., <script>alert('XSS')</script>) and inserts it into the 'comments' field when adding a new site via the /dcim/sites/add/ endpoint.
Step 3: Data Storage: The malicious payload is stored in the NetBox database associated with the site's comments.
Step 4: Administrator Interaction: An administrator views the site details, including the comments section.
Step 5: Payload Execution: The NetBox application renders the comments using GFM, which processes the user-supplied input. Because the input wasn't properly sanitized, the embedded JavaScript code executes within the administrator's browser.
Step 6: Attack Outcome: The malicious JavaScript code executes, potentially leading to credential theft, session hijacking, or other malicious actions.
The vulnerability stems from insufficient sanitization of user-supplied input within GFM (GitHub Flavored Markdown) rendered fields, specifically the 'comments' field within the /dcim/sites/add/ endpoint. The application fails to properly escape or filter HTML tags and JavaScript code embedded within the comments. When an administrator views the comments, the malicious JavaScript executes within their browser, leading to the XSS attack. The root cause is a lack of input validation and output encoding on the server-side, allowing unsanitized user input to be rendered directly in the administrator's browser.
While no specific APT groups are directly linked to this CVE, XSS vulnerabilities are commonly exploited by various threat actors. This vulnerability could be leveraged as part of a broader attack chain. This vulnerability is not listed on the CISA KEV list.
Monitor web server logs for suspicious HTTP requests containing JavaScript payloads in the 'comments' field or other GFM-rendered fields.
Analyze network traffic for unusual JavaScript execution or redirects originating from the NetBox instance.
Implement a Web Application Firewall (WAF) to detect and block XSS attempts.
Monitor for changes in user sessions, especially administrator sessions, that may indicate a compromise.
Review the NetBox database for unusual or unexpected entries in the 'comments' field.
Upgrade to NetBox version 2.6.3 or later, which includes a fix for this vulnerability.
Implement proper input validation and output encoding (e.g., HTML escaping) for all user-supplied input, especially within GFM-rendered fields.
Use a Content Security Policy (CSP) to restrict the execution of JavaScript from untrusted sources.
Regularly scan the NetBox instance for vulnerabilities.
Implement a WAF to filter malicious requests.
Review and harden the server configuration to minimize the attack surface.