All posts tagged update

Always On VPN Device Tunnel Issues with April 2024 Security Update

Always On VPN administrators may find that their device tunnel connections no longer connect automatically after applying the April 2024 security updates. The device tunnel connection is optional and only required under specific conditions, so end users may not be immediately impacted. However, administrators should be aware of this issue.

Note: The issues outlined in this post have been resolved with the May 14, 2024, security updates.

Error Messages

When manually establishing an Always On VPN device tunnel connection using rapshone.exe or rasdial.exe, you may receive one of the following error messages.

Rasphone.exe

Error 0x80070057: The parameter is incorrect.

Rasdial.exe

Connecting to <Name of Device Tunnel>…The parameter is incorrect.

Affected Devices

The issue affects all supported versions of Windows with an Always On VPN device tunnel connection configured to require a specific Enhanced Key Usage (EKU) OID. Administrators can run the following PowerShell command to identify this configuration.

Get-VpnConnection -AllUserConnection -Name <Name of Device Tunnel> | Select-Object MachineCertificateEkuFilter

If the output of this PowerShell command returns data, it is affected by this issue.

Workaround

To restore Always On VPN device tunnel functionality on devices with the April 2024 security updates installed, open an elevated PowerShell command window and run the following command.

Set-VpnConnection -AllUserConnection -Name ‘Always On VPN Device Tunnel’ -MachineCertificateEKUFilter $Null

After running this command, the output should now be blank.

Caveat

The problem with implementing the workaround described here is that you likely enabled this configuration to address an issue where the wrong certificate was selected for use with the device tunnel. In this case, the workaround may result in unexpected behavior and may not restore full functionality.

Known Issue Rollback

Currently, Microsoft is aware of the issue and is actively working to resolve it. If you are experiencing this issue, open a support case with Microsoft, and they will provide you with more information and possibly a private Known Issue Rollback (KIR). I will update this post as soon as Microsoft publishes a permanent fix.

Additional Information

Always On VPN Device Tunnel Operation and Best Practices

Always On VPN Device Tunnel Only Deployment Considerations

Considerations for Always On VPN with Azure VPN Gateway and Virtual WAN

2 Comments
by Richard M. Hicks on April 23, 2024  •  Permalink
Posted in Always On VPN, AOVPN, Certificate Authentication, certificates, device tunnel, Enterprise, enterprise mobility, IKEv2, Microsoft, Mobility, Operational Support, PowerShell, Remote Access, Security, Security Update, troubleshooting, Update, VPN, Windows 10, Windows 11
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Posted by Richard M. Hicks on April 23, 2024

https://directaccess.richardhicks.com/2024/04/23/always-on-vpn-device-tunnel-issues-with-april-2024-security-update/

Always On VPN April 2024 Security Updates

Microsoft has released its security updates for April 2024. This month, a few vulnerabilities are potentially impacting Always On VPN administrators. Specifically, three updates address issues with the Windows Server Routing and Remote Access Service (RRAS). In addition, vulnerabilities affect the Remote Access Connection Manager (RasMan) service, affecting both VPN servers and clients.

RRAS

Windows Server Routing and Remote Access (RRAS) has three security updates available this month. All three are Remote Code Execution (RCE) vulnerabilities but require user interaction to exploit the vulnerability. All three updates are rated as Important.

CVE-2024-26179

CVE-2024-26200

CVE-2024-26205

RasMan

In addition to the vulnerabilities in RRAS, Microsoft announced numerous updates for vulnerabilities discovered in the Remote Access Connection Manager (RasMan) service. These vulnerabilities are related to information disclosure via buffer overruns. These updates affect both Windows RRAS servers and Windows Always On VPN clients. All updates are rated as Important.

CVE-2024-26207

CVE-2024-26211

CVE-2024-26217

CVE-2024-26255

CVE-2024-28900

CVE-2024-28901

CVE-2024-28902

Recommendations

While none of these vulnerabilities are critical, Always On VPN administrators are urged to update their affected systems soon.

Additional Information

April 2024 Security Updates

6 Comments
by Richard M. Hicks on April 9, 2024  •  Permalink
Posted in Always On VPN, AOVPN, CVE, Enterprise, enterprise mobility, Hotfix, Infrastructure, Microsoft, Mobility, Operational Support, 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
Tagged , , , , , , , ,

Posted by Richard M. Hicks on April 9, 2024

https://directaccess.richardhicks.com/2024/04/09/always-on-vpn-april-2024-security-updates/

Always On VPN November 2023 Security Updates

Microsoft has released its security updates for November 2023. For Always On VPN administrators, it’s a light month, with just a single CVE affecting Always On VPN infrastructure.

PEAP

CVE-2023-36028 addresses a remote code execution (RCE) vulnerability in the Microsoft Protected Extensible Authentication Protocol (PEAP). An attacker could exploit this vulnerability by sending a specially crafted PEAP packet to a Windows Network Policy Server (NPS). This attack does not require authentication or user interaction.

Affected Systems

This PEAP vulnerability affects only NPS servers configured to support PEAP authentication explicitly. PEAP authentication is a best practice configuration for Always On VPN deployments and is widely deployed. NPS servers deployed to support other services, such as Wi-Fi or router and switch access that are configured to allow PEAP authentication, are also affected.

Exposure

NPS servers are not (or should not be!) exposed directly to the public Internet. This limits the attack surface to adversaries already on the internal network.

Mitigation

Microsoft suggests disabling PEAP authentication support on NPS servers until the update is applied. However, this would break the majority of Always On VPN deployments today. Since disabling PEAP isn’t a viable option, administrators can reduce their attack surface by updating the NPS firewall rules to restrict access only to authorized VPN servers or other network devices until their systems are fully updated.

Additional Information

November 2023 Security Updates

CVE-2023-36028 PEAP Remote Code Execution Vulnerability

4 Comments
by Richard M. Hicks on November 14, 2023  •  Permalink
Posted in Active Directory, administration, Always On VPN, AOVPN, authentication, CVE, EAP, Enterprise, enterprise mobility, Infrastructure, Microsoft, Mobility, network policy server, NPS, Operational Support, PEAP, Protected EAP, Remote Access, Security, Security Update, Update, user tunnel, VPN, Windows Server 2016, Windows Server 2019, Windows Server 2022
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Posted by Richard M. Hicks on November 14, 2023

https://directaccess.richardhicks.com/2023/11/14/always-on-vpn-november-2023-security-updates/

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