3.2 Set 'Require Client Certificates' to 'Required'

Information

Certificates can reside in the certificate store on a mobile device or on a smart card. A certificate authentication method uses the Extensible Authentication Protocol (EAP) and the Transport Layer Security (TLS) protocol. During EAP-TLS certificate authentication, the client and the server prove their identities to each other. For example, an Exchange ActiveSync client presents its user certificate to the Client Access server, and the Client Access server presents its computer certificate to the mobile device to provide mutual authentication.

Rationale:

The default behavior of Exchange is to only require Basic Authentication. This type of authentication occurs in plaintext, which increases the possibility that an attacker could capture a user's credentials. In addition to configuring this setting to require client certificates, you can further mitigate the risk that the default behavior poses by configuring IIS to require SSL or TLS user connections to the Exchange servers in your organization.

NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.

Solution

Please refer to the URL in the 'References' section below.

See Also

https://workbench.cisecurity.org/files/1512