All posts in category Protected EAP

Always On VPN and the PSPKI PowerShell Module

Certificates are a crucial part of a secure Always On VPN implementation. Certificates are phishing-resistant forms of authentication that, when configured correctly, provide robust and multifactor authentication for remote access users and devices.

AD CS

Most commonly, certificates are issued by an on-premises Microsoft Active Directory Certificate Services (AD CS) server. Administrators configure and deploy a Certification Authority infrastructure to issue and manage user and device authentication certificates in their organization. CA certificates are also required on the VPN server to support Always On VPN device tunnel connections and IKEv2 user tunnel connections. The NPS server also requires an enterprise CA certificate. Of course, the CA can issue certificates for other purposes, including Wi-Fi authentication, document signing, and code signing, just to name a few.

PSPKI

PSPKI is a PowerShell module available in the PowerShell Gallery for configuring, managing, and troubleshooting Microsoft AD CS. Created by Vadims Podans of PKI Solutions, PSPKI includes over 100 functions for various AD CS and certificate-related tasks. Always On VPN administrators will find this PowerShell module helpful when configuring and troubleshooting certificate-related issues for their Always On VPN deployments.

Note: The AD CS remote server administration tools (RSAT) must be installed to access all of the PSPKI module’s functionality.

Installation

Run the following PowerShell command to install the PSPKI PowerShell module.

Install-Module -Name PSPKI

Always On VPN and PSPKI

Always On VPN Administrators will immediately find a few PSPKI functions helpful when implementing and supporting Always On VPN.

Test-WebServerSSL – This function will connect to a remote web server and display details about the TLS certificate included in the response. This can be especially helpful when troubleshooting SSTP VPN connections.

Convert-PfxToPem – This is a handy utility for converting a PFX file to the PEM format. This is commonly required when importing CA certificates on non-Microsoft platforms, security devices, and load balancers.

Convert-PemToPfx – Occasionally, administrators must convert a certificate and private key in PEM format to PFX to install on a Windows server. This tool allows administrators to perform this task easily.

Get-CertificationAuthority – This function quickly enumerates all enterprise CA servers and displays information about their hostname, accessibility, service status, and type.

Ping-ICertInterface – This function helps troubleshoot CA connectivity issues. Administrators can quickly determine if a CA is reachable and capable of issuing a certificate using this command.

Get-CaTemplate – This command displays a list of certificate templates published on the specified target CA server. The certificate template’s display name and the minimum support CA version are provided. In addition, the output indicates if certificate autoenrollment is enabled on the template.

Much More

The PSPKI PowerShell module for AD CS has many tools for configuring and managing AD CS. PSPKI recently received a major update to version 4.0. Download and install PSPKI today. It will make your life easier, I can assure you!

Additional Information

PSPKI PowerShell Module – PowerShell Gallery

PSPKI PowerShell Module – GitHub

AOVPNTools PowerShell Module – PowerShell Gallery

AOVPNTools PowerShell Module – GitHub

InboxAccountingDatabaseManagement PowerShell Module

InboxAccontingDatabaseManagement – PowerShell Gallery

InboxAccountingDatabaseManagement – GitHub

4 Comments
by Richard M. Hicks on June 20, 2023  •  Permalink
Posted in Active Directory, administration, Always On VPN, AOVPN, authentication, certificates, Deployment, Encryption, Enterprise, enterprise mobility, GitHub, IKEv2, Infrastructure, Microsoft, Mobility, Multifactor Authentiction, NPS, Operational Support, PEAP, PKI, PowerShell, Protected EAP, public key infrastructure, Remote Access, routing and remote access service, RRAS, Secure Socket Tunneling Protocol, Security, SSL, SSL and TLS, SSTP, systems management, TLS, Transport Layer Security, troubleshooting, Update, user tunnel, VPN, Windows 10, Windows 11, Windows Server 2012 R2, Windows Server 2016, Windows Server 2019, Windows Server 2022
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Posted by Richard M. Hicks on June 20, 2023

https://directaccess.richardhicks.com/2023/06/20/always-on-vpn-and-the-pspki-powershell-module/

Always On VPN NPS and PEAP Vulnerabilities

The February 2023 security updates for Windows Server address multiple vulnerabilities that affect Microsoft Always On VPN administrators. This latest update addresses multiple critical and important vulnerabilities in the Network Policy Server (NPS), commonly used to perform RADIUS authentication for Always On VPN servers. Specifically, there are several Remote Code Execution (RCE) and Denial of Service (DoS) vulnerabilities with Protected Extensible Authentication Protocol (PEAP). PEAP with user authentication certificates is the authentication protocol of choice for Always On VPN user tunnel authentication.

Vulnerabilities

The following is a list of vulnerabilities in PEAP addressed in the February 2023 security update.

  • CVE-2023-21689 – Microsoft PEAP Remote Code Execution Vulnerability (critical)
  • CVE-2023-21690 – Microsoft PEAP Remote Code Execution Vulnerability (critical)
  • CVE-2023-21691 – Microsoft PEAP Information Disclosure vulnerability (important)
  • CVE-2023-21692 – Microsoft PEAP Remote Code Execution Vulnerability (critical)
  • CVE-2023-21695 – Microsoft PEAP Remote Code Execution Vulnerability (important)
  • CVE-2023-21701 – Microsoft PEAP Denial of Service Vulnerability (important)

Mitigation

Unauthenticated attackers can exploit the RCE vulnerabilities in PEAP on Microsoft Windows NPS servers. However, NPS servers should not be exposed directly to the Internet and would require an attacker to have access to the internal network already. However, administrators are advised to apply this update to their NPS servers as soon as possible. In addition, organizations that deploy the NPS role on enterprise domain controllers should update immediately.

Additional Information

February 2023 Update for Windows Server 2022 (KB5022842)

February 2023 Update for Windows Server 2019 (KB022840)

February 2023 Update for Windows Server 2016 (KB5022838)

2 Comments
by Richard M. Hicks on February 16, 2023  •  Permalink
Posted in Active Directory, administration, Always On VPN, AOVPN, authentication, certificates, Cryptography, Device Management, EAP, Encryption, Enterprise, enterprise mobility, extensible authentication protocol, Hotfix, Infrastructure, Microsoft, Mobility, network policy server, NPS, Operational Support, PEAP, Protected EAP, Remote Access, Security, Update, user tunnel, VPN, Vulnerability, Windows Server 2016, Windows Server 2019, Windows Server 2022
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Posted by Richard M. Hicks on February 16, 2023

https://directaccess.richardhicks.com/2023/02/16/always-on-vpn-nps-and-peap-vulnerabilities/

Always On VPN Error 853 on Windows 11

Recently I did some validation testing with Always On VPN on Windows 11, and I’m happy to report that everything seems to work without issue. However, a few readers have reported 853 errors when establishing an Always On VPN connection after upgrading to Windows 11.

Can’t Connect

After upgrading to Windows 11, an Always On VPN connection may fail with the following error message.

“The remote access connection completed, but authentication failed because the certificate that authenticates the client to the server is not valid. Ensure the certificate used for authentication is valid.”

Error 853

In addition, the Application event log records an event ID 20227 from the RasClient source that includes the following message.

“The user <username> dialed a connection name <connection name> which has failed. The error code returned on failure is 853.”

Server Identity

This error will occur when using Protected Extensible Authentication Protocol (PEAP) authentication. Specifically, it can happen when the option to verify NPS server validity by its certificate is selected, and an explicit list of NPS servers is defined, as shown here.

Case Sensitive

In this specific scenario, Windows 11 now appears to be case-sensitive when it compares the NPS server name entered in the NPS configuration to the Subject Name on the certificate returned by the server. For example, if the Subject Name (or Subject Alternative Name, if present) entry on the NPS server certificate is nps.lab.richardhicks.net, using NPS.lab.richardhicks.net will not match and return an 853 error.

Windows 11

Case matching when validating the NPS server certificate is a change in behavior from Windows 10. Before Windows 11, this comparison was case-insensitive, and any combination of case would match if the entire hostname matched. Going forward, it appears Microsoft has also decided to require case matching to validate the server certificate.

Recommendations

Administrators should look carefully at the server certificate issued to the NPS server and ensure their client configuration accurately reflects the hostname in a case-sensitive manner to ensure a smooth migration from Windows 10 to Windows 11.

Additional Information

Troubleshooting Windows 10 Always On VPN Error 853

Windows 10 Always On VPN Network Policy Server (NPS) Load Balancing

22 Comments
by Richard M. Hicks on September 23, 2021  •  Permalink
Posted in Always On VPN, AOVPN, authentication, certificates, EAP, Enterprise, enterprise mobility, extensible authentication protocol, Mobility, Name Resolution, network policy server, NPS, PEAP, Protected EAP, Remote Access, Security, troubleshooting, VPN, Windows 11
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Posted by Richard M. Hicks on September 23, 2021

https://directaccess.richardhicks.com/2021/09/23/always-on-vpn-error-853-on-windows-11/

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