All posts tagged RRAS

Always On VPN and NPS AD Registration

Always On VPN Users Prompted for Certificate

Windows Server Network Policy and Access Services (NPAS, more commonly called NPS) is a popular solution used in Always On VPN deployments to support Active Directory authentication for user-based VPN connections. NPS is integrated with Active Directory to perform certificate-based authentication. With additional configuration, NPS can apply specific settings to an individual connection by reading the properties of the user’s AD account.

Dial-In Properties

Administrators can allow or deny network access, assign a static IP address, or assign a static route on a per-user basis. This information is defined on the Dial-In tab of the user account in Active Directory Users and Computers (dsa.msc).

Register in AD

Registering the NPS server in Active Directory is strictly optional. It is not required to perform user authentication. However, administrators must register the NPS server in Active Directory to assign connection properties per user. Active Directory registration for NPS allows the NPS server to read the properties of individual Active Directory user accounts. Active Directory registration for NPS is accomplished in one of several ways.

NPS Management Console

On each NPS server, open the NPS management console (nps.msc), right-click the server, and choose Register server in Active Directory.

Command Line

Administrators can register the NPS server in Active Directory by opening an elevated command window and running the following command.

netsh.exe nps add registeredserver <domain> <host>

Where <domain> is the Active Directory domain where you want to add the NPS server to the RAS and IAS Servers security group, and <host> is the hostname of the NPS server to register.

For example:

netsh.exe nps add registeredserver lab.richardhicks.net nps1

ADUC

Registering an NPS server in Active Directory does nothing more than add the NPS server to the RAS and IAS Servers domain security group. Administrators can open ADUC and add NPS servers to the group directly if required.

Note: Registering an NPS server in Active Directory using the NPS console or the command line adds the NPS server to the RAS and IAS Servers group in the domain to which the NPS server belongs. If user accounts are in a different domain, NPS servers must also be added to the RAS and IAS Servers group in those domains.

NPS Policy

In addition to registering the NPS server in Active Directory, administrators must ensure that the option to Ignore user account dial-in properties on the Network Policy used for Always On VPN is not checked.

Additional Information

Always On VPN and NPS Server Load Balancing

Always On VPN NPS Auditing and Logging

Always On VPN NPS RADIUS Configuration Missing

4 Comments
by Richard M. Hicks on February 6, 2024  •  Permalink
Posted in Always On VPN, Authentication and MFA, NPS and EAP, Windows Server
Tagged , , , , , , ,

Posted by Richard M. Hicks on February 6, 2024

https://directaccess.richardhicks.com/2024/02/06/always-on-vpn-and-nps-ad-registration/

Always On VPN and IPv6

Internet Protocol version 6 (IPv6) has been with us for nearly 30 years. IPv6 adoption on the public Internet has steadily increased over the last decade, and today is approaching 50%. However, enterprise adoption of IPv6 has been surprisingly sluggish despite its numerous benefits. IPv6 includes an expanded address space that removes complex subnetting requirements and globally unique addressing that eliminates the need to perform Network Address Translation (NAT), among others. Organizations should consider deploying IPv6 internally to take advantage of these capabilities.

IPv6 and RRAS

I’ve deployed Microsoft Always On VPN for customers using IPv6 numerous times. The following describes configuration settings required to support IPv6 in a Microsoft environment using a Windows Server Routing and Remote Access (RRAS) server.

To begin, open the Routing and Remote Access management console (rrasmgmt.msc) on the RRAS VPN server, then follow the steps below to enable IPv6 support for Always On VPN connections.

Note: The configuration below assumes that IPv6 is already deployed on the internal network, either natively or dual-stacked with IPv4.

IPv6 Remote Access

Perform the following steps to enable IPv6 remote access on the RRAS VPN server.

  1. Right-click the RRAS VPN server in the navigation tree and choose Properties.
  2. Check the box next to the IPv6 Remote access server on the General tab.

Prefix Assignment

Next, an IPv6 prefix must be assigned to each RRAS VPN server. This IPv6 prefix must be unique for each server and not in use anywhere else on the internal network. Unlike IPv4, IPv6 addresses cannot be assigned from the same prefix (subnet) as the VPN server’s internal network interface. With that, ensure that internal network IPv6 routing returns traffic for the assigned IPv6 prefixes to the corresponding VPN server.

Perform the following steps to assign an IPv6 prefix for VPN client use.

  1. Right-click the RRAS VPN server in the navigation tree and choose Properties.
  2. Select the IPv6 tab.
  3. Check the box next to Enable IPv6 Forwarding.
  4. If force tunneling is required (not recommended), check the box next to Enable Default Route Advertisement.
  5. Enter an IPv6 prefix in the IPv6 prefix assignment field. Again, ensure the IPv6 prefix is globally unique, and that internal network routing is configured to return traffic to the VPN server that owns the prefix.
  6. If your RRAS server is multi-homed, select the internal network interface from the Adapter drop-down list.

DHCP

Organizations with IPv6 deployed internally may use Microsoft Windows DHCPv6 or a dedicated DNS/DHCP/IP Address Management (IPAM) (DDI) solution like Infoblox. However, Windows Server RRAS does not support DHCPv6 for VPN client IP address assignment. Administrators must manually assign an IPv6 prefix per server. However, administrators can use DHCP alongside IPv6 prefix assignment for VPN client IPv4 addressing.

Limitations

While IPv6 may solve some problems for Always On VPN administrators, it has some limitations. Here are some crucial considerations for IPv6 and Always On VPN at the time of this writing.

Traffic Filters

You cannot use IPv6 when configuring traffic filters for Always On VPN. Specifying IPv6 elements in a traffic filter rule will prevent Always On VPN from working at all. More details here.

Intune and Routing

When split tunneling is enabled, Microsoft Intune will not accept IPv6 routes using the standard IPv6 subnet prefix of /64. The UI complains that “the value must be between 1 and 32”.

You can use the custom XML deployment option to configure Always On VPN to support split tunneling correctly as a workaround.

Additional Information

Overview of IPv6

Everything You Never Knew about NAT

Disabling IPv6 Breaks Windows Server RRAS

Microsoft Always On VPN Traffic Filters and IPv6

Discussing Microsoft and IPv6 on the IPv6 Buzz Podcast (Packet Pushers)

6 Comments
by Richard M. Hicks on January 22, 2024  •  Permalink
Posted in Always On VPN, IPv6, Microsoft Intune, Windows Server
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Posted by Richard M. Hicks on January 22, 2024

https://directaccess.richardhicks.com/2024/01/22/always-on-vpn-and-ipv6/

Always On VPN RRAS Centralized Monitoring and Reporting

A while back, I wrote about the monitoring and reporting options for Windows Server Routing and Remote Access (RRAS) servers supporting Microsoft Always On VPN. In that article, I outlined how administrators can use the Routing and Remote Access Management console (rrasmgmt.msc) or the Remote Access Management console (ramgmtui.exe) to perform configuration tasks and review current user and device activity. However, neither solution is ideal in a distributed environment with multiple RRAS servers. Thankfully, there’s a new option available to address this crucial limitation today.

Centralized Reporting

I’m excited to announce the availability of a cloud-based, centralized reporting solution for Windows Server RRAS and Always On VPN from the folks at PowerON Platforms. Created by the folks that brought us the Dynamic Profile Configurator (DPC) solution for managing Always On VPN client configuration settings, PowerON Platforms’ new reporting solution allows administrators to aggregate configuration, performance, and user activity data from multiple individual RRAS servers across their organization.

Important! I’ll be joining the folks at PowerON Platforms for a webinar on Thursday, January 18 to introduce and demonstrate this new Always On VPN reporting solution. Register now!

Summary View

The Summary view page provides a consolidated high-level look at the environment’s health status and capacity of VPN servers. Administrators can quickly see if any servers are unhealthy and view current usage details to assess the capacity of the deployment.

Server Overview

The Server Overview page provides a more detailed look at individual server health status and configuration. Here, you’ll find information about the number of active and available connections and the TLS certificate status. In addition, you’ll find detailed information about provisioned CPU and RAM, disk space utilization, and system uptime. You will also see information about the size of the reporting database on disk and the number of IKEv2 and SSTP VPN ports provisioned.

VPN Server Configuration

The VPN Server Configuration page looks into the IP address pool configuration and current utilization. In addition, this page provides an in-depth look at the VPN server TLS certificate health status. Currently, configured authentication and accounting servers are also shown.

Server Performance

The Server Performance page shows granular details about resource utilization on RRAS servers. This includes CPU and memory utilization, disk space usage, and database size. Administrators can view aggregated data or select individual servers. The view can be further customized by filtering by date.

Connection History

The Connection History page details concurrent connections observed on all VPN servers. Data can be filtered by date, individual server, and user or device name.

Client Distribution

The Client Distribution page provides an intuitive graphical display of client activity by server and tunnel type. In addition, it includes details about usage by individual clients and the number of connections made by individual endpoints.

Connection Detail

The Connection Detail page allows administrators to view user activity across all servers in the organization. Once again, data can be filtered by date, individual server, and user or device name. This view provides granular details on user activity, enabling the administrator to drill down to view specific resources accessed over the VPN for individual sessions.

Data Flow

The Data Flow page displays information about data transfer through the VPN server.

Summary

The Always On VPN cloud-based centralized reporting solution for Microsoft Always On VPN by PowerON Platforms is sure to be helpful for organizations managing distributed RRAS server deployments. The reporting solution aggregates data from all RRAS servers in the enterprise, providing a holistic view of configuration, health status, and user activity in one management console. This consolidated visibility is crucial for capacity planning and configuration maintenance, making the identification of performance bottlenecks or misconfigured servers easy. Also, the ability to view certificate expiration status for all servers in the organization is sure to prevent outages. Security administrators will find the solution helpful for forensic reporting and to identify sources of data leakage and exfiltration.

You can contact PowerON Platforms and request additional information here.

More Information

Are you interested in learning more about PowerON Platforms Always On VPN reporting? Would you like an interactive solution demonstration or an evaluation license to trial the product in your environment? Fill out the form below, and I’ll contact you with more details.

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by Richard M. Hicks on January 9, 2024  •  Permalink
Posted in Always On VPN, Always On VPN DPC, Training and Events, Windows Server
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Posted by Richard M. Hicks on January 9, 2024

https://directaccess.richardhicks.com/2024/01/09/always-on-vpn-rras-centralized-monitoring-and-reporting/

10 PowerShell Commands Always On VPN Administrators Should Know

Managing a secure and reliable VPN infrastructure is critical for supporting today’s highly mobile workforce. For Always On VPN administrators, PowerShell is an indispensable tool for achieving this goal. Not only can PowerShell be used to automate the installation and configuration of Windows Server Routing and Remote Access Service (RRAS) server, but it can also be used to audit configuration and monitor system health and user activity as well. In addition, it is highly recommended that the RRAS role be installed on Server Core for optimum security and performance. Administrators must be familiar with these PowerShell commands and more to support RRAS on Windows Server Core in their environment.

RemoteAccess Module

The RemoteAccess PowerShell module should be installed when the RRAS server is configured. There are 122 commands in this module, but only a subset of those pertain to the VPN server role. Here are ten popular commands for monitoring and managing an Always On VPN RRAS server.

Configuration Review

The following PowerShell commands are useful for reviewing the current RRAS server configuration.

Get-RemoteAccess – Displays the current configuration of the VPN server. Details include installation status, TLS certificate configuration, VPN client IP address assignment method, IPv4 and IPv6 addressing information (if using the static address assignment method), authentication type, and configured RADIUS servers.

Get-VpnAuthProtocol – Displays authentication configuration details such as accepted authentication types for both user and device connections, root certification authority (CA) certificate restrictions (if enabled), and certificate advertisement and EKU restrictions if enabled.

Get-VpnServerConfiguration – Displays additional VPN server configuration information, such as the IPsec configuration for IKEv2, the number of VPN ports configured, and more.

System Health

Get-RemoteAccessHealth – Displays the current health status of various VPN server services. The command’s default output is a little noisy. I recommend filtering it as follows:

Get-RemoteAccessHealth | Where-Object HealthState -NotMatch Disabled | Format-Table -AutoSize

User Activity

The following PowerShell commands can be used to view current and historical user activity details.

Get-RemoteAccessConnectionStatistics – Displays all active VPN connections on the server.

Get-RemoteAccessConnectionStatisticsSummary – Displays cumulative information about VPN connections on the server since the last service restart or reboot, such as the total number of connections, the number of unique users, the maximum number of concurrent connections, and the amount of data transferred.

Get-RemoteAccessUserActivity – Displays all active VPN connections for a specific user or device.

Management

The following PowerShell commands are helpful for reviewing authentication and logging settings.

Get-RemoteAccessRadius – Allows the administrator to view the currently configured RADIUS servers on the VPN server.

Get-RemoteAccessAccounting – Allows the administrator to view the current accounting repository (RADIUS or inbox) on the VPN server.

Clear-RemoteAccessInboxAccountingStore – Allows the administrator to remove log data from the Inbox Accounting database. Removing log data from the database can be helpful when transitioning a test server to production or to free up disk space by reducing the size of the logging database.

Additional Modules

In addition to the PowerShell commands above, Always On VPN administrators can leverage my custom PowerShell modules for advanced server and client configuration. These modules are published in the PowerShell Gallery.

AovpnTools – PowerShell module to configure and optimize Windows RRAS servers to support Always On VPN.

Install-Module -Name AovpnTools

InboxAccountingDatabaseManagement – PowerShell module to configure and manage the Inbox Accounting database for logging system information and user activity on the VPN server.

Install-Module -Name InboxAccountingDatabaseManagement

Additional Information

Always On VPN and RRAS on Windows Server Core

Inbox Accounting Database Management

AovpnTools PowerShell Module on GitHub

Inbox Accounting Database Module on GitHub

2 Comments
by Richard M. Hicks on November 2, 2023  •  Permalink
Posted in Always On VPN, Microsoft Intune, PowerShell, Windows Server
Tagged , , , , , , , , ,

Posted by Richard M. Hicks on November 2, 2023

https://directaccess.richardhicks.com/2023/11/02/10-powershell-commands-always-on-vpn-administrators-should-know/

Always On VPN October 2023 Security Updates

Once again, it’s time to patch! After several quiet months, there are a few crucial updates Always On VPN administrators will want to get deployed soon. Thankfully, the impact of the security updates related to Always On VPN is low this time, as there is only one Remote Code Execution (RCE) vulnerability, and it’s for a legacy protocol that should be in limited use today.

IKEv2

CVE-2023-36726 addresses a security vulnerability in Windows Internet Key Exchange (IKE) that can lead to privilege escalation. An attacker who successfully exploits this vulnerability can elevate privileges to that of the local SYSTEM.

L2TP

This month’s update discloses several Layer Two Tunneling Protocol (L2TP) vulnerabilities. The following CVEs all address a vulnerability where an attacker can send a specially crafted protocol message to a Windows Routing and Remote Access Service (RRAS) server, which could lead to remote code execution on the server.

Mitigation

The impact of the L2TP security vulnerabilities should be minimal in most organizations. L2TP is a legacy VPN protocol not commonly used for Always On VPN. However, misconfiguration can leave vulnerable RRAS servers exposed. Administrators must ensure that inbound UDP port 1723 is not open from the Internet. In addition, L2TP should be disabled on the RRAS server if not in use. See the article on the May 2023 security updates for details.

Additional Information

October 2023 Security Updates

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by Richard M. Hicks on October 10, 2023  •  Permalink
Posted in Always On VPN, Security Updates, Windows Server
Tagged , , , , , , , , , , , ,

Posted by Richard M. Hicks on October 10, 2023

https://directaccess.richardhicks.com/2023/10/10/always-on-vpn-october-2023-security-updates/

Always On VPN and RRAS on Windows Server Core

Windows Server Core is a refactored version of the full Windows Server operating system. Server Core does not include a Graphical User Interface (GUI) and must be managed via the command line or with PowerShell. The Routing and Remote Access Service (RRAS) is a supported workload on all supported versions of Windows Server including Windows Server 2022. Always On VPN administrators should consider installing and configuring RRAS on Windows Server Core to ensure their VPN infrastructure’s best security and performance.

Server Core Benefits

Windows Server Core is a minimal installation option of the Windows Server operating system that provides numerous benefits, particularly for environments where security, resource efficiency, and reduced maintenance overhead are essential. Here are some of the key benefits of using Windows Server Core.

Minimized Attack Surface – Windows Server Core has a smaller footprint compared to the full GUI version, which means fewer components and services are installed by default. This reduces the potential attack surface and minimizes security vulnerabilities.

Enhanced Security – With fewer components and a reduced attack surface, there are fewer potential vectors for malware or unauthorized access. This makes Windows Server Core a more secure choice for critical server roles like RRAS.

Reduced Maintenance – Since there are fewer components to update, patching and maintaining a Windows Server Core system is quicker and requires less effort. This is especially beneficial in large-scale server deployments.

Improved Stability – By removing the graphical user interface (GUI), Windows Server Core has fewer processes running in the background, leading to a more stable and predictable server environment.

Simplified Management – Windows Server Core is designed for remote administration. It allows the administrator to manage it using command-line tools, PowerShell, or remote management tools like the Remote Server Administration Tools (RSAT) and Windows Admin Center. This makes it easier to manage multiple servers from a single location.

Faster Reboots – Windows Servers require periodic reboots. With Windows Server Core, reboot times are considerably faster, resulting in less downtime during maintenance periods.

RSAT

The Remote Server Administration Tools (RSAT) can be installed on Windows clients and servers to enable remote administration using the familiar Routing and Remote Access Management console (rrasmgmt.msc) and Remote Access Management console (ramgmtui.exe) GUI tools.

Windows Client

To install the Remote Access Management tools on Windows client operating systems, navigate to Settings > Apps > Optional Features. Click Add a feature, select RSAT: Remote Access Management Tools, then click Install.

Optionally the Remote Access Management tools can be installed by running the following PowerShell command.

Add-WindowsCapability -Online -Name Rsat.RemoteAccess.Management.Tools~~~~0.0.1.0

Windows Server

To install the Remote Access Management tools on Windows Server run the following PowerShell command.

Install-WindowsFeature -Name RSAT-RemoteAccess

Windows Admin Center

The Windows Admin Center is a free remote management tool from Microsoft for managing Windows Server (core and GUI) remotely. It is especially helpful for Server Core management as it provides a GUI for many common administrative tasks.

You can download Windows Admin Center here.

Additional Information

Windows Server Core Installation Option

Windows Server Core vs. Desktop

PowerShell Remote Server Administration

Windows Admin Center

2 Comments
by Richard M. Hicks on October 2, 2023  •  Permalink
Posted in Always On VPN, PowerShell, Windows Server
Tagged , , , , , , , , , , ,

Posted by Richard M. Hicks on October 2, 2023

https://directaccess.richardhicks.com/2023/10/02/always-on-vpn-and-rras-on-windows-server-core/

Windows Server 2012 and 2012 R2 End of Life

DirectAccess on Microsoft Windows

I want to remind you of a critical upcoming milestone that may affect your business. In just 60 days, we will reach the end of support for Windows Server 2012 and Windows Server 2012 R2. As of October 10, 2023, these operating systems will no longer receive security updates or technical support from Microsoft.

End of Support

End of support means your servers will be more vulnerable to security risks and potential threats. It is essential to take action now to ensure your IT infrastructure’s continued security and stability. Upgrading to newer, supported operating systems will protect your data and systems from potential cyber threats and provide access to enhanced features and performance improvements.

Don’t Wait

Now is the time to migrate those remaining workloads for those still running Windows Server 2012 and 2012 R2! Consider the following commonly deployed services that may still be running on Windows Server 2012 or 2012 R2 in your organization.

Remote Access – Windows Server Routing and Remote Access Service (RRAS) is commonly deployed to provide secure remote access for field-based workers. In addition, Absolute Secure Access (formerly NetMotion Mobility) is a widely implemented premium alternative to RRAS. Organizations may be hesitant to migrate these workloads because disrupting remote workers is painful.

DirectAccess – This remote access technology is widely deployed and extremely difficult to migrate. In addition, the complex nature of DirectAccess, with its many intricate interdependencies, poses a significant challenge to organizations migrating this role.

PKI – This is likely the most common enterprise service to be found running on Windows Server 2012 and 2012R2. Most organizations relying on Windows Active Directory Certificate Services (AD CS) to issue and manage enterprise certificates are reluctant to move this workload once it is deployed. This service is much easier to migrate than you might think! It can be done without disruption as well.

Consulting Services

We understand that upgrading might require careful planning and coordination, and our team is here to support you throughout the transition process. Don’t delay – take this opportunity to safeguard your organization’s data and systems by upgrading to the latest Windows Server version or exploring cloud-based solutions.

Get In Touch

Please don’t hesitate to contact us for further assistance or any questions regarding the upgrade process. Together, let’s ensure your business remains secure and productive. You can get started today by booking a free one-hour consultation to discuss your migration strategy. Just fill out the form below and I’ll provide more information.

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by Richard M. Hicks on August 14, 2023  •  Permalink
Posted in Always On VPN, Consulting Services, DirectAccess, PKI, Windows Server
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Posted by Richard M. Hicks on August 14, 2023

https://directaccess.richardhicks.com/2023/08/14/windows-server-2012-and-2012-r2-end-of-life/

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 Always On VPN, Load Balancing, Microsoft Intune, PKI, Security Updates, Windows Server
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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 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 Always On VPN, PowerShell, Security Updates, TLS, Windows Server
Tagged , , , , , , , , ,

Posted by Richard M. Hicks on May 9, 2023

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

Always On VPN April 2023 Security Updates

Heads up, Always On VPN administrators! This month’s patch Tuesday includes fixes for critical security vulnerabilities affecting Windows Server Routing and Remote Access Service (RRAS). Crucially there are remote code execution (RCE) vulnerabilities in the Point-to-Point Tunneling Protocol (PPTP) (CVE-2023-28232), the Layer Two Tunneling Protocol (L2TP) (CVE-2023-28219, CVE-2023-28220), the Point-to-Point over Ethernet (PPPoE) protocol (CVE-2023-28224), and the Internet Key Exchange (IKE) protocol (CVE-2023-28238). The vulnerabilities in PPTP and L2TP are especially urgent as they allow an unauthenticated attacker to exploit them. There is also a denial-of-service (DoS) vulnerability (CVE-2023-28234) in the Secure Socket Tunneling Protocol (SSTP) protocol.

Exposure and Risk

The RCEs in PPTP, L2TP, and PPPoE should present limited risk as these protocols aren’t commonly used for Always On VPN (PPPoE and PPTP aren’t supported for Always On VPN, in fact). However, organizations may be using these protocols for other purposes. In addition, improperly configured edge firewalls could allow these connections even though administrators may not be actively using them. An attacker could also exploit these vulnerabilities with access to the RRAS server from the internal network.

Attack Surface Reduction

Always On VPN administrators are advised to ensure that only protocols and ports for VPN protocols in use are allowed through the edge firewall. Also, administrators should disable any unused protocols and services in RRAS to reduce the attack surface on their RRAS servers. To do this, open an elevated PowerShell command window on the RRAS server and run the following commands to disable support for the PPTP, L2TP, and PPPoE protocols.

netsh.exe ras set wanports device = “WAN Miniport (L2TP)” rasinonly = disabled ddinout = disabled ddoutonly = disabled maxports = 0

netsh.exe ras set wanports device = “WAN Miniport (PPTP)” rasinonly = disabled ddinout = disabled ddoutonly = disabled maxports = 1

netsh.exe ras set wanports device = “WAN Miniport (PPPOE)” ddoutonly = disabled

Restart-Service RemoteAccess -PassThru

Additional Vulnerabilities

This month’s update also includes fixes for other vulnerabilities that may impact Always On VPN deployments. Specifically, there are RCEs in Windows Network Address Translation (NAT) (CVE-2023-28217) and Windows Network Load Balancing (NLB) (CVE-2023-28240), and a DoS vulnerability in Windows Transport Layer Security (TLS) (CVE-2023-28234).

Update Now

Administrators should patch their RRAS servers as soon as possible to avoid potential compromise of the RRAS server in their environments.

Additional Information

Always On VPN SSTP Security Configuration

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by Richard M. Hicks on April 12, 2023  •  Permalink
Posted in Always On VPN, Authentication and MFA, PowerShell, Security Updates, TLS, Windows Server
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Posted by Richard M. Hicks on April 12, 2023

https://directaccess.richardhicks.com/2023/04/12/always-on-vpn-april-2023-security-updates/

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