Appendix B Authentication in ACS 5.3

Certificate Attributes

Certificate Attributes

ACS parses the following client certificate’s attributes:

Certificate serial-number (in binary format)

Encoded certificate (in binary DER format)

Subject’s CN attribute

Subject’s O attribute (Organization)

Subject’s OU attribute (Organization Unit)

Subject’s L attribute (Location)

Subject’s C attribute (Country)

Subject’s ST attribute (State Province)

Subject’s E attribute (eMail)

Subject’s SN attribute (Subject Serial Number)

SAN (Subject Alternative Name)

You can define a policy to set the principle username to use in the TLS conversation, as an attribute that is taken from the received certificate.

The attributes that can be used as the principle username are:

Subject CN

Subject Serial-Number (SN)

SAN

Subject

SAN—Email

SAN—DNS

SAN—otherName

If the certificate does not contain the configured attribute, authentication fails.

Note ACS 5.3 supports short hard-coded attributes and certificate attribute verification for the only the EAP-TLS protocol.

Certificate Binary Comparison

You can perform binary comparison against a certificate that ACS receives from an external identity store and determine the identity store's parameters that will be used for the comparison.

Note In ACS 5.3, LDAP is the only external identity store that holds certificates.

ACS uses the configured principle username to query for the user's certificate and then perform binary comparison between the certificate received from external identity store and the one received from the client. The comparison is performed on a DER certificate format.

 

User Guide for Cisco Secure Access Control System 5.3

B-32

OL-24201-01

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Cisco Systems OL-24201-01 manual Certificate Attributes, Certificate Binary Comparison, San-Dns