X-aspnet-version 4.0.3 Vulnerabilities

For custom applications, follow secure coding practices. This includes validating inputs to prevent SQL injection and XSS attacks.

When an ASP.NET application handles a request (e.g., .aspx , .ashx , or MVC routes), the runtime automatically appends a response header similar to:

A typical reconnaissance attack chain:

Exposing the version number is not a vulnerability per se , but it signals the presence of a known-weak platform. Below are critical vulnerabilities affecting .NET 4.0.3 (unpatched unless migrated to 4.5+).

Response.Headers.Remove("X-AspNet-Version"); x-aspnet-version 4.0.3 vulnerabilities

The X-AspNet-Version: 4.0.30319 HTTP header is a common sight in automated penetration testing reports. While it often triggers a "low" or "medium" severity alert for , the real danger lies in what this header reveals about the underlying system’s potential for critical exploits like Remote Code Execution (RCE) or Authentication Bypass . 1. What is X-AspNet-Version: 4.0.30319 ?

Though not a direct vulnerability of ASP.NET itself, applications built using ASP.NET 4.0.3 are susceptible to SQL injection attacks if they interact with databases in insecure ways. This can allow attackers to execute arbitrary SQL commands. For custom applications, follow secure coding practices

When an attacker sees this header, they know the server is running a version of .NET Framework 4.x. If the server is not regularly patched via Windows Update , it may be susceptible to legacy vulnerabilities tied to the 4.0 runtime. 2. Major Known Vulnerabilities

Certain systems using this CLR version, such as NetAdmin IAM , have been found to allow attackers to steal and inject session cookies for unauthorized access. 3. The Risk of Information Disclosure Below are critical vulnerabilities affecting