Restricting proxy users

The PingDirectory server provides a set of operational attributes that restrict the proxied authorization capabilities of a client application and its proxyable target entry.

When present in an entry, the PingDirectory server evaluates each operational attribute together to form a whitelist of potential users that can be proxied. If none of those attributes are present, the user can potentially proxy as anyone.

The PingDirectory server supports a two-tier provision system that can restrict specific users for proxied authorization:

The first tier is a set of ds-auth-may-proxy-as-* operational attributes on the client entry that binds to the server and carries out operations under the identity of another user.
The second tier is a set of ds-auth-is-proxyable-* operational attributes on the user entry that defines whether access is allowed, prohibited, or required through proxied authorization. If proxied authorization is allowed or required, the attributes define which client entries can proxy as the user.

Proxying operational attributes

For example, the following command demonstrates the client application uid=clientApp requesting to search the ou=People,dc=example,dc=com branch as the user uid=admin.

ldapsearch --bindDN uid=clientApp,dc=example,dc=com \
--bindPassword password \
--proxyAs uid=admin,dc=example,dc=com \
--baseDN ou=People,dc=example,dc=com \
"(object-class=*)

At bind, the PingDirectory server evaluates the list of users in the uid=clientApp entry based on the presence of any ds-auth-may-proxy-as-* attributes.

In the previous figure, the uid=clientApp entry has a ds-auth-may-proxy-as attribute with a value of uid=admin, meaning the client app user can proxy only as the uid=admin account.

Next, the server confirms that uid=admin is in the list of proxyable users and then evaluates the ds-auth-is-proxyable-* attributes present in the uid=admin entry. These attributes determine the list of restricted users that either are allowed, prohibited, or required to proxy as the uid=admin entry. In this case, the uid=admin entry has the ds-auth-is-proxyable attribute with a value of required, meaning the entry can only be accessed by means of proxied authorization.

The uid=admin entry also has the ds-auth-is-proxyable-by attribute with a value of uid=clientApp, meaning it can only be requested by the uid=clientApp entry. When both sets of attributes have been satisfied, the uid=clientApp can bind to the server as the authenticated user.

Next, the PingDirectory server performs access control instruction (ACI) evaluation on the branch and determines if the requested user has access rights to the branch. If the uid=clientApp entry can access the branch, the search request is processed.

About the ds-auth-may-proxy-as-* operational attributes

The PingDirectory server first evaluates the list of potential users that can be proxied for the authenticated user depending on the presence of the ds-auth-may-* operational attributes in the entry.

These operational attributes are multi-valued and are evaluated together if all are present in an entry:

ds-auth-may-proxy-as: Specifies the user distinguished names (DNs) that the associated user can proxy as. For example, you can specify in the uid=clientApp entry that it can proxy operations as uid=admin and uid=agent1.

dn: uid=clientApp,ou=Applications,dc=example,dc=com
objectClass: top
...
ds-privilege-name: proxied-auth
ds-auth-may-proxy-as: uid=admin,dc=example,dc=com
ds-auth-may-proxy-as: uid=agent1,ou=admins,dc=example,dc=com

ds-auth-may-proxy-as-group: Specifies the group DNs and its group members that the associated user can proxy as. For example, you can specify that the potential users that the uid=clientApp entry can proxy as are those members who are present in the group cn=Agents,ou=Groups,dc=example,dc=com. This attribute is multi-valued, so you can specify more than one group. Nested static and dynamic groups are also supported.

dn: uid=clientApp,ou=Applications,dc=example,dc=com
objectClass: top
...
ds-privilege-name: proxied-auth
ds-auth-may-proxy-as-group: cn=Agents,ou=Groups,dc=example,dc=com

ds-auth-may-proxy-as-url: Specifies the DNs that are returned based on the criteria defined in an LDAP URL that the associated user can proxy as. For example, the attribute specifies that the client can proxy as those entries that match the criteria in the LDAP URL. This attribute is multi-valued, so you can specify more than one LDAP URL.

dn: uid=clientApp,ou=Applications,dc=example,dc=com
objectClass: top
...
ds-privilege-name: proxied-auth
ds-auth-may-proxy-as-url: ldap:///ou=People,dc=example,dc=com??sub?(l=austin)

About the ds-auth-is-proxyable-* operational attributes

After the PingDirectory server evaluates the list of users that the authenticated user can proxy as, the server checks to see if the requested authorized user is in the list.

If the requested authorized user is present in the list, then the server continues processing the proxable attributes in the entry. If the requested authorized user is not present in the list, the bind fails.

The operational attributes on the proxying entry are as follows:

ds-auth-is-proxyable

Specifies whether the entry is proxyable or not. Possible values are:

allowed: Operations can be proxied as this user.
prohibited: Operations can’t be proxied as this user.
required: The account cannot authenticate directly but can only be accessed by some form of proxied authorization.

ds-auth-is-proxyable-as

Specifies any users allowed to use this entry as a target of proxied authorization.

ds-auth-is-proxyable-as-group

Specifies any groups allowed to use this entry as a target of proxied authorization. Nested static and dynamic groups are also supported.

ds-auth-is-proxyable-as-url

Specifies the LDAP URLs that are used to determine any users that are allowed to use this entry as a target of proxied authorization.