Microsoft Entra Global Secure Access

Last week Microsoft introduced new Security Service Edge (SSE) capabilities as part of the Microsoft Entra suite of technologies. Included in these announcements, Microsoft introduced the public preview of two new secure remote access technologies – Microsoft Entra Internet Access and Microsoft Entra Private Access. The latter of these will particularly interest Microsoft Always On VPN administrators in some deployment scenarios.

Microsoft Entra Internet Access

Microsoft Entra Internet Access is a new Secure Web Gateway (SWG) cloud service solution designed to protect users from threats on the public Internet. Features include web content filtering, malware inspection, TLS inspection, and more. In addition, Entra Internet Access can protect Microsoft 365 applications. Azure Conditional Access policies can be enforced for Internet traffic. Network conditions are now included with Azure Conditional Access, which can further protect against attacks by requiring access from specific trusted or compliant networks. Today, the public preview is available for Microsoft 365 scenarios only. Internet traffic and other SaaS applications will be available later this year.

Microsoft Entra Private Access

Microsoft Entra Private Access is a Zero Trust Network Access (ZTNA) cloud service solution that leverages the Azure Application Proxy access model. With Azure App Proxy, administrators can easily publish private, on-premises web applications by installing the connector on an on-premises server. Administrators can leverage Azure AD authentication and conditional access policies to ensure device compliance or enforce multifactor authentication (MFA), if required. Microsoft Entra Private Access extends the capabilities of the Azure Application Proxy to support TCP and UDP-based applications.

Private Access vs. Always On VPN

Microsoft Entra Private Access will be a compelling alternative to Always On VPN in the future. Specifically, organizations using native Azure AD join devices could benefit tremendously from this technology. Microsoft Entra Private Access is much simpler to implement than Always On VPN and requires no on-premises infrastructure other than the Azure Application Proxy connector. Using Microsoft Entra Private Access also means that no inbound access from the Internet is required, making the solution inherently more secure and reducing the public attack surface. For organizations using hybrid Azure AD join, Always On VPN continues to be the best Microsoft solution for these scenarios.

References

Microsoft Entra Expands into Security Service Edge (SSE)

Microsoft Entra – Secure Access for a Connected World

Microsoft Entra Internet Access Preview

Microsoft Entra Private Access Preview

What is Zero Trust?

What is Zero Trust Network Access?

What is Security Service Edge (SSE)?

What is Secure Access Service Edge (SASE)?

What’s the Difference Between SSE and SASE?

Contact Us

I’ve had the privilege of participating in the private preview for Microsoft Entra Internet Access and Private Access. If you’d like to learn more about these technologies and how they can help your organization, fill out the form below, and I’ll provide more information.

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)

Azure Conditional Access Certificates with SID Information Now Available

I recently wrote about changes to certificate-based authentication affecting Always On VPN implementations. These changes were introduced by Microsoft’s security update KB5014754. When the update is installed on domain controllers and enterprise Certification Authorities (CAs), administrators can perform strong user mapping for certificates used for Active Directory authentication. However, when first introduced, the update came with some serious limitations that prevented administrators from enabling full enforcement mode for certificate mapping.

Limitations

When KB5014754 is installed on an enterprise issuing CA, a new certificate extension (1.3.6.1.4.1.311.25.2) is added to the issued certificate that includes the principal’s (user or device) Security Identifier (SID). However, this only occurs when an online template is used. An online template is one with the subject name built from Active Directory information. The SID is not embedded in certificates issued using an offline template. Offline templates are templates where the subject name is supplied in the request. There are two scenarios where this causes problems for Always On VPN.

Microsoft Intune

Certificates delivered with Microsoft Intune via the Intune Certificate Connector use an offline template. This applies to certificates using PKCS or SCEP. Today, the SID is not embedded by issuing CAs using offline templates.

Azure Conditional Access

The short-lived certificate issued by Azure when Conditional Access is configured for Always On VPN did not include the SID. However, that recently changed.

Recent Updates

Today we can scratch Azure Conditional Access off the list of limitations for Always On VPN. Microsoft recently introduced support for the new SID extension in Azure Conditional Access certificates, as shown here.

Now when an Azure Conditional Access certificate is issued to an on-premises user or device account that is synced with Azure Active Directory, Azure Conditional Access will include the SID information in the issued short-lived certificate.

Intune

Unfortunately, we’re still waiting for Microsoft to address the limitation with certificates delivered using Microsoft Intune. Hopefully we’ll see an update for that later this year.  

Additional Information

Certificate-Based Authentication Changes and Always On VPN

Microsoft KB5014754

Digital Certificates and TPM

Microsoft Intune Certificate Connector Service Account and PKCS

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