All posts in category routing and remote access service

Always On VPN July 2023 Security Updates

Hello, Always On VPN administrators! It’s the second Tuesday of the month, so you know what that means. Yes, it’s Patch Tuesday! This month’s security updates include several fixes for vulnerabilities potentially affecting Microsoft Always On VPN deployments.

RRAS Vulnerabilities

Microsoft’s July 2023 security updates include fixes affecting Windows Servers with the Routing and Remote Access Service (RRAS) role installed. Security vulnerabilities CVE-2023-35365, CVE-2023-35366, and CVE-2023-35367 are all Remote Code Execution (RCE) vulnerabilities with a Critical security rating and a CVSS score of 9.8. These security vulnerabilities in Windows Server RRAS are particularly troublesome due to the nature of the workload. RRAS servers are, by design, exposed to the public Internet. Although there are no known exploits in the wild at this time, this attack requires no special privileges other than network access. Administrators running Windows Server with RRAS installed are encouraged to update as soon as possible.

AD CS Vulnerabilities

Most Always On VPN implementations leverage enterprise PKI certificates for user and device authentication. Administrators commonly deploy Microsoft Active Directory Certificate Services (AD CS) to support this. This month there are two security vulnerabilities in AD CS marked as Important. CVE-2023-35350 and CVE-2023-35351 address RCE vulnerabilities that exploit a race condition on the server. However, AD CS servers are not exposed to untrusted networks. In addition, attackers would require administrative rights on the server to exploit these vulnerabilities.

Network Load Balancing

Finally, of importance to Always On VPN administrators using Windows Network Load Balancing (NLB) to provide load balancing for their RRAS servers, there is a vulnerability in the NLB service. CVE-2023-33163 addresses an RCE vulnerability in NLB identified as Important.

Additional Information

Microsoft July 2023 Security Updates

Windows Server 2022 KB5028171 (Build 20348.1850)

Windows Server 2019 KB5028168 (Build 17763.4645)

Windows Server 2016 KB 5028169 (Build 14393.6085)

Windows 11 22H2 KB8028185 (Build 22621.1992)

Windows 11 21H2 KB5028182 (Build 22000.2176)

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by Richard M. Hicks on July 11, 2023  •  Permalink
Posted in Active Directory, Active Directory Certificate Services, AD CS, administration, Always On VPN, AOVPN, Certificate Services, certificates, CVE, Deployment, Device Management, Enterprise, enterprise mobility, Hotfix, Infrastructure, Load Balancing, Microsoft, Mobility, Operational Support, PKI, public key infrastructure, Remote Access, routing and remote access service, RRAS, Security, Security Update, Update, VPN, Vulnerability, Windows 10, Windows 11, Windows Server 2016, Windows Server 2019, Windows Server 2022
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Posted by Richard M. Hicks on July 11, 2023

https://directaccess.richardhicks.com/2023/07/11/always-on-vpn-july-2023-security-updates/

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

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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 May 2023 Security Updates

Hey, Always On VPN administrators! It’s the second Tuesday of the month, which means security updates for Windows have been released. This month’s batch includes an update to address a critical vulnerability likely to affect many Always On VPN implementations using Windows Server.

SSTP Vulnerability

CVE-2023-24903 documents a vulnerability on Windows Servers with the Routing and Remote Access Service (RRAS) configured to support Secure Socket Tunneling Protocol (SSTP) for VPN connections. This is a remote code execution (RCE) vulnerability that can be exploited when an attacker sends a specifically crafted malicious packet to the server. Administrators are encouraged to update as soon as possible.

Mitigation

SSTP is commonly used for Always On VPN user tunnels. However, if administrators have configured user tunnels using IKEv2, or are using the device tunnel only, consider blocking inbound TCP 443 at the edge firewall to prevent attacks from the Internet. In addition, if SSTP is not in use, consider disabling support for SSTP by opening an elevated PowerShell command window and running the following commands.

netsh.exe RAS set wanports device = “WAN Miniport (SSTP)” rasinonly = disabled ddinout = disabled ddoutonly = disabled maxports = 0

Restart-Service RemoteAccess -PassThru

Alternatively, SSTP can be disabled in the RRAS management console by following the steps below.

  1. Open the RRAS management console (rrasmgmt.msc).
  2. Expand the server.
  3. Right-click Ports.
  4. Choose Properties.
  5. Highlight WAN Miniport (SSTP).
  6. Click Configure.
  7. Uncheck Remote access connections (inbound only).
  8. Uncheck Demand-dial routing connections (inbound and outbound).
  9. Enter 0 in the Maximum ports field.
  10. Click Ok.

Additional Information

Windows SSTP Remote Code Execution Vulnerability (CVE-2023-24903)

May 2023 Security Updates for Windows Server 2016 (KB5026363)

May 2023 Security Updates for Windows Server 2019 (KB5026362)

May 2023 Security Updates for Windows Server 2022 (KB5026370)

1 Comment
by Richard M. Hicks on May 9, 2023  •  Permalink
Posted in administration, Always On VPN, AOVPN, device tunnel, Enterprise, enterprise mobility, IKEv2, Infrastructure, Microsoft, Mobility, Operational Support, PowerShell, Remote Access, routing and remote access service, RRAS, Secure Socket Tunneling Protocol, Security, SSTP, TLS, Update, user tunnel, VPN, Windows 10, Windows 11, Windows Server 2016, Windows Server 2019, Windows Server 2022
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Posted by Richard M. Hicks on May 9, 2023

https://directaccess.richardhicks.com/2023/05/09/always-on-vpn-may-2023-security-updates/

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