Microsoft Net Framework 4.0 V 30319 Vulnerabilities

This article provides a deep dive into the security standing of .NET Framework 4.0, why the version number "30319" persists, and how to protect applications in the current threat landscape. 1. What is .NET Framework 4.0 v4.0.30319?

When an automated scanner detects this specific header, it often cross-references the string with legacy CVE databases compiled for the raw, unpatched 2010 release of .NET Framework 4.0. This superficial check results in a if the host server actually runs a modern, patched version of the framework that simply utilizes the same legacy CLR engine.

While the runtime receives continual updates through the Windows Update system, the original —the specific product released in 2010—has reached its End of Life (EOL) . According to Microsoft's lifecycle policy, mainstream support for .NET Framework 4.0 ended on January 12, 2016 . This means that Microsoft will no longer release security updates specifically for the standalone .NET Framework 4.0 installer.

5.0 (Medium) Vector: Information Disclosure microsoft net framework 4.0 v 30319 vulnerabilities

An attacker submits a malicious XML file containing a reference to an external URI.

Every subsequent release in the .NET 4.x family—.NET 4.5, 4.6, 4.7, and 4.8—continues to run on top of .

When a web server emits the header X-AspNet-Version: 4.0.30319 , it confirms the server runs the , but it does not specify whether the framework layer is the deprecated .NET 4.0 or a fully patched, modern version like .NET 4.8. This article provides a deep dive into the

If you see 4.0.30319 in a production environment today, it is to all patched .NET Framework issues from 2016 onward.

Over the years, numerous Common Vulnerabilities and Exposures (CVEs) have targeted the components housed inside the v4.0.30319 architecture:

If .NET 4.0 is obsolete, why does it remain a primary target in threat reports? When an automated scanner detects this specific header,

| CVE | Impact | Exploitability on 4.0 RTM | |------|--------|----------------------------| | CVE-2017-8759 | RCE | High | | CVE-2017-8585 | EoP | High | | CVE-2015-2545 | RCE | High | | CVE-2017-11770 | RCE | High | | CVE-2018-8260 | RCE | Medium-High | | CVE-2019-0545 | RCE | High | | CVE-2017-0283 | RCE | Medium |

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\.NETFramework\v4.0.30319 Harden Application Code

Analysis of Microsoft .NET Framework 4.0 (v4.0.30319) Security Vulnerabilities Executive Summary

Legacy .NET web applications (ASP.NET) running on version 4.0 are vulnerable to XML External Entity (XXE) injections and hash collision attacks. An attacker can send a specially crafted HTTP request or XML payload that forces the CPU utilization to 100%, effectively crashing the web service for legitimate users. 4. Security Feature Bypass

registry key, which meant their legacy app was still trying to communicate over weak, outdated TLS protocols.