If you are looking for a MFA solution for Cisco AnyConnect then there is a good chance that you have heard of Duo and Azure AD. In this blog post I will guide you through the configuration steps required to set up Azure MFA with Cisco AnyConnect. Having Cisco ISE is optional for this to work.
- You want to authenticate the AnyConnect users against Azure SSO/SAML to enforce MFA.
- Authorization should happen against Cisco ISE to provide role-based access using SGT tags << optional
- You already have a working ASA AnyConnect setup
- Authentication and authorization works with ISE
- Users and groups are already synced with Azure AD
- Cisco ISE is configured with Authorization policies for each AD group.
- ISE advertises SGT mappings to ASA via SXP
- ACLs are configured on ASA with SGs
- ASA running 9.8 or later code, and AnyConnect clients will be 4.6+
Adding Cisco AnyConnect from the gallery
To configure the integration of Cisco AnyConnect into Azure AD, you need to add Cisco AnyConnect from the gallery to your list of managed SaaS apps.
- Sign in to the Azure portal
- On the left navigation pane, select the Azure Active Directory service.
- Navigate to Enterprise Applications and then select All Applications.
- Select New Application
- type Cisco AnyConnect in the search box.
- Select Cisco AnyConnect from results
Configure Azure AD SSO
Configure Azure AD SSO
Go to AnyConnect application and then select Set up single sign on
Set up single sign-on with SAML page, enter the values for the following fields:
In the Identifier text box, type Cisco ASA RA VPN "Tunnel group" name
In the Reply URL text box, type Cisco ASA RA VPN "Tunnel group" name
On the Set up single sign-on with SAML page, in the SAML Signing Certificate section, find Certificate (Base64) and select Download to download the certificate file and save it on your computer.
On the Set up Cisco AnyConnect section, copy all three URLs.
Cisco ASA configuration
Assume the tunnel-group name is "company-vpn" , VPN url is "vpn.mycompany.com" and the trust-point of the identity certificate is "my-public-cert"
VPN Identity Certificate - Usually a wild card certificate for *.mycompany.com that you buy from a CA.
Create a trust-point and import the SAML certificate you downloaded in the previous step.
crypto ca trustpoint Azure-saml revocation-check none no id-usage no ca-check enrollment terminal crypto ca authenticate Azure-saml -----BEGIN CERTIFICATE----- ***certificate goes here*** -----END CERTIFICATE----- quit
Configure SAML IdP
webvpn enable OUTSIDE anyconnect-essentials anyconnect image disk0:/anyconnect-win-4.5.04029-webdeploy-k9.pkg 1 anyconnect image disk0:/anyconnect-linux64-4.5.04029-webdeploy-k9.pkg 5 anyconnect image disk0:/anyconnect-macos-4.5.04029-webdeploy-k9.pkg 6 anyconnect enable tunnel-group-list enable cache disable error-recovery disable saml idp https://sts.windows.net/fgg54-4fdd-ac56-3ad156472a14/ url sign-in https://login.microsoftonline.com/3d-ac563/saml2 url sign-out https://login.microsoftonline.com/common/wsfederation?wa=wsignout1.0 base-url https://vpn.mycompany.com trustpoint idp Azure-saml trustpoint sp my-public-cert no signature force re-authentication
For Service Provider (SP) certificate you can use the identity or wild card certificate associated with your VPN url (vpn.mycompany.com) This certificate is usually issued by public CA.
Apply SAML authentication to the VPN tunnel group
tunnel-group mycompany-vpn webvpn-attributes authentication saml group-alias mycompany-vpn enable saml identity-provider https://sts.windows.net/fgg54-4fdd-ac56-3ad156472a14/
Now users should be able to login to AnyConnect via SSO. But we want to make sure that ISE is performing the Authorization.
To achieve this we need to use the authorization feature on the ASA. This will enable ASA to authenticate users against Azure AD and authorize against ISE.
When the authorization request comes to ISE, it tries to process a full authentication + authorization. There is no password (because Azure handled it already) in the packet so the authentication fails.
To get around the issue we need to set the ISE authentication source to Internal Users, and told ISE to continue on both Auth fail and user not found. This allows ISE to process just authorization.
tunnel-group mycompany-vpn general-attributes authorization-server-group ISE
Cisco ISE configuration
This would allow ISE to process the authorization and everything should work correctly. You can enforce MFA using Azure "Conditional Access".
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