SSL built-in actions and user-defined actions

Unless you need only the built-in actions in your policies, you have to create the actions before creating the policies, so that you can specify the actions when you create the policies. The built-in actions are of two types, control actions and data actions. You use control actions in control policies, and data actions in data policies.

The built-in control actions are:

• CLIENTAUTH—Perform client certificate authentication.
• NOCLIENTAUTH—Do not perform client certificate authentication.

The built-in data actions are:

• RESET—Close the connection by sending a RST packet to the client.
• DROP—Drop all packets from the client. The connection remains open until the client closes it.
• NOOP—Forward the packet without performing any operation on it.

You can create user-defined data actions. For example, if you enable client authentication, you can create an SSL action to insert client-certificate data into the request header before forwarding the request to the web server.

If a policy evaluation results in an undefined state, an UNDEF action is performed. For either a data policy or a control policy, you can specify RESET, DROP, or NOOP as the UNDEF action. For a control policy, you also have the option of specifying CLIENTAUTH or NOCLIENTAUTH.

Examples of built-in actions in a policy

In the following example, if the client sends a cipher other than an EXPORT category cipher, the Citrix ADC appliance requests client authentication. The client has to provide a valid certificate for a successful transaction.

add ssl policy pol1 -rule CLIENT.SSL.CIPHER_EXPORTABLE.NOT -reqAction CLIENTAUTH 

The following examples assume that client authentication is enabled.

If the version in the certificate provided by the user matches the version in the policy, no action is taken and the packet is forwarded:

add ssl policy pol1 -rule CLIENT.SSL.CLIENT_CERT.VERSION.EQ(2) -reqAction NOOP 

If the version in the certificate provided by the user matches the version in the policy, the connection is dropped:

add ssl policy pol1 -rule CLIENT.SSL.CLIENT_CERT.VERSION.EQ(2) -reqAction DROP 

If the version in the certificate provided by the user matches the version in the policy, the connection is reset:

add ssl policy pol1 -rule CLIENT.SSL.CLIENT_CERT.VERSION.EQ(2) -reqAction RESET 

User-defined SSL actions

In addition to built-in actions, you can also configure other SSL actions depending on your deployment. These are called user-defined actions.

Configure a user-defined SSL action by using the CLI

At the command prompt, type the following commands to configure an action and verify the configuration:

add SSL action  -clientAuth(DOCLIENTAUTH | NOCLIENTAUTH) -clientCert (ENABLED | DISABLED) certHeader  -clientHeader  -clientCertSerialNumber (ENABLED | DISABLED) -certSerialHeader  -clientCertSubject (ENABLED | DISABLED) -certSubjectHeader  -clientCertHash (ENABLED | DISABLED) -certHashHeader  -clientCertIssuer (ENABLED | DISABLED) -certIssuerHeader  -sessionID (ENABLED | DISABLED) -sessionIDheader  -cipher (ENABLED | DISABLED) -cipherHeader  -clientCertNotBefore (ENABLED | DISABLED) -certNotBeforeHeader  -clientCertNotAfter (ENABLED | DISABLED) -certNotAfterHeader  -OWASupport (ENABLED | DISABLED) 

show ssl action [] 

Example:

add ssl action Action-SSL-ClientCert -clientCert ENABLED -certHeader "X-Client-Cert" 

show ssl action Action-SSL-ClientCert 1) Name: Action-SSL-ClientCert Data Insertion Action: Cert Header: ENABLED Cert Tag: X-Client-Cert Done 

Configure a user-defined SSL action by using the GUI

导航到交通管理> > SSL策略d, on the Actions tab, click Add.

配置SSL行动向前端traffic to another virtual server

Note: This feature is available in release 12.1 build 49.x and later.

Admins can configure an SSL action to forward the client traffic received on an SSL virtual server to another virtual server to avoid SSL offloading or terminating the connection on the ADC appliance. For example, if the appliance does not have a certificate or it does not support a specific cipher, instead of terminating the connection, admins can choose to forward the request to another virtual server for further action. This virtual server can be of type: SSL, TCP, or SSL_BRIDGE.

To achieve the above, a new bind point ‘CLIENTHELLO_REQ’ is added to evaluate client traffic when a client hello is received. If the policy bound to the virtual server receiving client traffic evaluates to true after parsing the client hello, the traffic is forwarded to another virtual server. If this virtual server is of type SSL, it performs the handshake. If this virtual server is of type TCP or SSL_BRIDGE, the backend server performs the handshake.

In release 12.1-49.x, only the forward and reset actions are supported for CLIENTHELLO_REQ bind point. The following expression prefixes are available:

• CLIENT.SSL.CLIENT_HELLO.CIPHERS.HAS_HEXCODE
• CLIENT.SSL.CLIENT_HELLO.CLIENT_VERSION
• CLIENT.SSL.CLIENT_HELLO.IS_RENEGOTIATE
• CLIENT.SSL.CLIENT_HELLO.IS_REUSE
• CLIENT.SSL.CLIENT_HELLO.IS_SCSV
• CLIENT.SSL.CLIENT_HELLO.IS_SESSION_TICKET
• CLIENT.SSL.CLIENT_HELLO.LENGTH
• CLIENT.SSL.CLIENT_HELLO.SNI

For a description of these prefixes, seeAdvanced policy expressions: parsing SSL

A new parameter ‘forward’ is added to the ‘add SSL action’ command and new bind point ‘CLIENTHELLO_REQ’ is added to the ‘bind ssl vserver’ command.

Configuration using the CLI

At the command prompt, type:

add ssl action  -forward  add ssl policy  -rule  -action  bind ssl vserver  -policyName  -priority  -type  

EXAMPLE:

add ssl action act1 -forward v2 add ssl policy pol1 -rule client.ssl.client_hello.ciphers.has_hexcode(0x002f) -action act1 bind ssl vserver v1 -policyName pol1 -priority 1 -type CLIENTHELLO_REQ 

Configuration using the GUI

Navigate to Traffic Management > SSL > Policies.

Create SSL action:

1. InSSL Actions, clickAdd.
2. InCreate SSL Action, specify a name for the action.
3. InForward Action Virtual Server, select an existing virtual server or add a new virtual server to forward the traffic to.
4. Optionally, set other parameters.
5. ClickCreate.

Create SSL policy:

1. InSSL Policies, clickAdd.
2. InCreate SSL Policy, specify a name for the policy.
3. InAction, select the action that you created above.
4. InExpression Editor, enter the rule to evaluate.
5. ClickCreate.

Create or add a virtual server and bind policy:

1. Navigate toTraffic Management>Load Balancing>Virtual Servers.
2. Add or select a virtual server.
3. InAdvanced Settings, clickSSL Policies.
4. Click in the SSL Policy section.
5. InSelect Policy, select the policy that you created earlier.
6. InPolicy Binding, specify a priority for the policy.
7. InType, selectCLIENTHELLO_REQ.
8. ClickBind.
9. ClickDone.

For the end-to-end configuration for the most popular use cases, seeConfigure SSL action to forward client traffic if the appliance does not have a domain specific (SNI) certificateandConfigure SSL action to forward client traffic if a cipher is not supported on the ADC.

SSL action to selectively pick CAs based on SNI for client authentication

Citrix ADC版本12.1开始建造50。c x,你an send only the list of CAs based on SNI (domain) in the client certificate request rather than the list of all the CAs bound to an SSL virtual server. For example, when a client hello is received, only the CA certificates based on the SSL policy expression (for example, SNI) are sent. To send a specific set of certificates, you must create a CA certificates group, bind this group to an SSL action, and bind the action to an SSL policy. If the policy bound to the virtual server receiving client traffic evaluates to true after parsing the client hello, only a specific CA certificates group is sent in the client request certificate.

Earlier, you had to bind CA certificates to an SSL virtual server. With this enhancement, you can simply add CA certificate groups and associate them to an SSL action.

Note:Client authentication and SNI must be enabled on the SSL virtual server, and the correct SNI certificates must be bound to the virtual server.

Perform the following steps:

1. Add a CA certificate group.

2. Add certificate-key pairs.

3. Bind the certificate-key pairs to this group.

4. Add an SSL action.

5. Add an SSL policy. Specify the action in the policy.

6. Bind the policy to an SSL virtual server. Specify the bind point as CLIENTHELLO_REQ.

Configuration using the CLI

At the command prompt, type the following commands in a sequence:

添加ssl caCertGroup < caCertGroupName >添加ssl证书key  -cert  -key  bind ssl caCertGroup   add ssl action  -caCertGrpName  add ssl policy  -rule  -action  bind ssl vserver  -policyName  -priority  -type CLIENTHELLO_REQ 

Example:

add ssl cacertGroup ca_cert_group add ssl certkey ca_certkey1 -cert cacert1 -key cakey1 add ssl certkey ca_certkey2 -cert cacert2 -key cakey2 add ssl certkey snicert -cert snicert -key snikey bind ssl cacertGroup ca_cert_group ca_certkey1 bind ssl caCertGroup ca_cert_group ca_certkey2 

sh ssl caCertGroup ca_cert_group CA GROUP NAME: ca_cert_group ACTIONS REFERRING: 1 1) CertKey Name: ca_certkey1 CA Certificate CRLCheck: Optional CA_Name Sent 2) CertKey Name: ca_certkey2 CA Certificate CRLCheck: Optional CA_Name Sent 

add ssl action pick_ca_group -cacertGrpName ca_cert_group 

sh ssl action pick_ca_group 1) Name: sniaction Type: Data Insertion PickCaCertGroup: ca_cert_group Hits: 0 Undef Hits: 0 Action Reference Count: 1 

add ssl policy snipolicy -rule client.ssl.client_hello.sni.contains("abc") -action pick_ca_group bind ssl vserver v_SSL -policyName snipolicy -type CLIENTHELLO_REQ -priority 10 

sh ssl policy snipolicy Name: pol1 Rule: client.ssl.client_hello.sni.contains("abc") Action: pick_ca_group UndefAction: Use Global Hits: 0 Undef Hits: 0 Policy is bound to following entities 1) Bound to: CLIENTHELLO_REQ VSERVER v_SSL Priority: 10 

set ssl vserver v_SSL -clientauth ENABLED -SNIEnable ENABLED bind ssl vserver v_SSL -certkeyName snicert -sniCert 

sh ssl vserver v_SSL Advanced SSL configuration for VServer v_SSL: DH: DISABLED DH Private-Key Exponent Size Limit: DISABLED Ephemeral RSA: ENABLED Refresh Count: 0 Session Reuse: ENABLED Timeout: 120 seconds Cipher Redirect: DISABLED SSLv2 Redirect: DISABLED ClearText Port: 0 Client Auth: ENABLED Client Cert Required: Mandatory SSL Redirect: DISABLED Non FIPS Ciphers: DISABLED SNI: ENABLED OCSP Stapling: DISABLED HSTS: DISABLED HSTS IncludeSubDomains: NO HSTS Max-Age: 0 SSLv2: DISABLED SSLv3: ENABLED TLSv1.0: ENABLED TLSv1.1: ENABLED TLSv1.2: ENABLED TLSv1.3: DISABLED Push Encryption Trigger: Always Send Close-Notify: YES Strict Sig-Digest Check: DISABLED Zero RTT Early Data: DISABLED DHE Key Exchange With PSK: NO Tickets Per Authentication Context: 1 ECC Curve: P_256, P_384, P_224, P_521 1) CertKey Name: snicert Server Certificate for SNI Data policy 1) Policy Name: snipolicy Priority: 10 1) Cipher Name: DEFAULT Description: Default cipher list with encryption strength >= 128bit 

Configuration using the GUI

Create CA certificates group and bind certificates to the group:

1. Navigate to Traffic Management > SSL > CA Certificates Group.
2. Click Add and specify a name for the group.
3. Click Create.
4. Select the CA certificate group and then click Show Bindings.
5. Click Bind.
6. In the CA Certificate Binding page, select an existing certificate or click Add to add a new certificate.
7. Click Select and then click Bind.
8. To bind another certificate, repeat steps 5 through 7.
9. Click Close.

Navigate to Traffic Management > SSL > Policies.

Create SSL action:

1. InSSL Actions, clickAdd.
2. InCreate SSL Action, specify a name for the action.
3. InForward Action Virtual Server, select an existing virtual server or add a new virtual server to forward the traffic to.
4. Optionally, set other parameters.
5. ClickCreate.

Create SSL policy:

1. InSSL Policies, clickAdd.
2. InCreate SSL Policy, specify a name for the policy.
3. InAction, select the action that you created above.
4. InExpression Editor, enter the rule to evaluate.
5. ClickCreate.

Create or add a virtual server and bind policy:

1. Navigate toTraffic Management>Load Balancing>Virtual Servers.
2. Add or select a virtual server.
3. InAdvanced Settings, clickSSL Policies.
4. Click in the SSL Policy section.
5. InSelect Policy, select the policy that you created earlier.
6. InPolicy Binding, specify a priority for the policy.
7. InType, selectCLIENTHELLO_REQ.
8. ClickBind.
9. ClickDone.

Unbind a CA certificate group by using the GUI

1. Navigate to Traffic Management > SSL > CA Certificates Group.
2. Select a certificate group and click Show Bindings.
3. Select the certificate to remove from the group and click Unbind.
4. If prompted for confirmation, click Yes.
5. Click Close.

Remove a CA certificate group by using the GUI

1. Navigate to Traffic Management > SSL > CA Certificates Group.
2. Select a certificate group and click Delete.
3. If prompted for confirmation, click Yes.