topic EAP-FAST With MFA in Wireless

EAP-FAST With MFA

NETAD — Mon, 05 Jul 2021 15:49:41 GMT

Hi, is it possible to deploy EAP-FAST without the anyconnect NAM module? I'm trying to use the option from the windows drop down list for the authentication methods but getting the attached error message and ISE complaining about not finding the authentication method.

Thanks

Re: EAP-FAST With MFA

Flavio Miranda — Mon, 09 Jul 2018 21:03:58 GMT

From Cisco docs:

EAP-FAST Error Messages and Prompts

Error Message    Automatic PAC provisioning is enabled for this profile. However, a 
valid PAC that matches the server to which the client adapter is connecting could 
not be found. Do you wish to obtain a new security credential (PAC)?

Recommended Action Click Yes to provision a new PAC for this server using your existing credentials or click No to cancel the operation. If you click No, the client adapter will fail the authentication."

https://www.cisco.com/c/en/us/td/docs/wireless/wlan_adapter/cb21ag/user/vista/1-0/configuration/guide/cb21ag10vistaconfigguide/messages_ap.html

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Re: EAP-FAST With MFA

NETAD — Mon, 09 Jul 2018 22:00:54 GMT

Hi Flavio, thanks. Is the anyconnect client necessary to configure EAP-FAST?

Re: EAP-FAST With MFA

Flavio Miranda — Mon, 09 Jul 2018 22:54:29 GMT

Don't think so. However, looks like this EAP method is not used anymore. Are you using Windows XP? Windows 7 and 10 seems not support anymore.

Looks like EAP TLS or PEAP is currently available.

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Re: EAP-FAST With MFA

NETAD — Mon, 09 Jul 2018 23:10:58 GMT

We're using Windows 7 and Windows 10. you mean EAP-Fast isn't supported on those anymore with or without the anyconnect client?

Re: EAP-FAST With MFA

stsargen — Tue, 17 Jul 2018 17:55:37 GMT

If you are not currently using NAM and using the Native supplicant for EAP-Fast you most likely have the EAP-Plugins that were provided to Microsoft years ago. You can still download them from a few different location, one of which is in the Surface bundle here.

https://www.microsoft.com/en-us/download/details.aspx?id=46703

That said, for multi-factor auth you will probably want the inner method of EAP-Fast to use GTC, and not MSCHAPv2. From the screenshot you provided the inner method sent to ISE was MSCHAPv2, and ISE tried to send this off to presumably your MFA server, and the server rejected it. I suspect the server is expecting GTC. I don't know your entire setup, but going off what you said this is my best guess.

Thanks,

Steve S.

Re: EAP-FAST With MFA

NETAD — Tue, 17 Jul 2018 18:35:37 GMT

This windows native supplicant kept doing mschapv2 for the inner tunnel. I ended up using the anyconnect profile editor to create a profile for EAP-FAST with EAP-GTC and it worked.

One last question. Does EAP-FAST require a cert on ISE or this is just with PEAP?

Thanks

Re: EAP-FAST With MFA

stsargen — Tue, 17 Jul 2018 18:55:16 GMT

EAP-Fast does not require the use of client or server certificates when performing unauthenticated provisioning. The tunnel is established using anonymous DH (Diffie Hellman) exchange (less secure, not recommended). If you use authenticated provisioning the TLS tunnel is established using the ISE server certificate.

This doc explains a lot of this in detail.

https://www.cisco.com/c/en/us/support/docs/wireless-mobility/eap-fast/200322-Understanding-EAP-FAST-and-Chaining-imp.html

PEAP always requires the server certificate.