Neto CMS CRLF Injection Vulnerability Allowing Arbitrary Code Execution

A CRLF injection vulnerability has been identified in Neto CMS versions 6.313.0 prior to 6.314.0. This vulnerability allows attackers to execute arbitrary code by sending a crafted HTTP request. The issue arises from improper handling of user-supplied paths and headers, which can be exploited to manipulate HTTP response headers and inject malicious content into the response body. This exploitation leads to reflected cross-site scripting (XSS) and other security issues such as CORS violations and account takeover.

Impact

Exploitation of this vulnerability allows for reflected cross-site scripting, which can be used to hijack sessions and accounts. It also bypasses web application firewalls like Cloudflare, enabling the execution of injected scripts that could be chained with other client-side vulnerabilities.

Reproduction

To reproduce this vulnerability, inject CRLF sequences into a URL path. When the server processes the request, it incorrectly handles the CRLF injection by storing the path as a cookie. This allows for the injection of arbitrary headers, such as Content-Type, and the embedding of malicious payloads into the response body. The injected content is then executed by the browser, resulting in reflected XSS.

Remediation

Users are advised to upgrade to Neto CMS version 6.3.15.0 or later. After updating, it is recommended to apply strict input validation for URL paths and parameters, ensuring CRLF characters are sanitized before being included in HTTP responses. Additionally, enforce Content-Type headers on error pages and deploy Content Security Policy (CSP) headers to prevent script injection.