Install and Renew Certificates on ASA Managed by CLI

Introduction

This document describes how to request, install, trust, and renew, certain types of certificates on Cisco ASA Software managed with CLI.

Prerequisites

Requirements

Cisco recommends that you have knowledge of these topics:

• Verify that the Adaptive Security Appliance (ASA) has the correct clock time, date, and time zone. With certificate authentication, it is recommended to use a Network Time Protocol (NTP) server to synchronize the time on the ASA. Check Related Information for reference.
• To request a certificate that uses Certificate Signing Request (CSR), it requires access to a trusted internal or third-party Certificate Authority (CA). Examples of third-party CA vendors include, but are not limited to, Entrust, Geotrust, GoDaddy, Thawte, and VeriSign.

Components Used

The information in this document is based on these software and hardware versions:

• ASAv 9.18.1
• For PKCS12 creation, OpenSSL is used.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, ensure that you understand the potential impact of any command.

Background Information

The type of certificates this document addresses are self-signed certificates, certificates signed by a 3rd party Certificate Authority, or internal CA, on Cisco Adaptive Security Appliance Software managed with Command Line Interface (CLI).

Trusted CA Security Considerations

Certificate Authentication Risks and Recommendations

Default Trustpoint Validation-Usage Behavior

When a trusted CA certificate is installed, with crypto ca trustpoint authenticate,it can be used to authenticate different types of VPN connections using certificate authentication. It is controlled with validation-usage trustpoint command. The validation-usage types are:

• ipsec-client: Validates IPsec client connections.
• ssl-client: Validates SSL client connections.
• ssl-server: Validates SSL server certificates.

By default, the command allows validation for ipsec-client and ssl-client.

Default Configuration Risks

• Any CA certificate installed as trusted can be used by default to authenticate incoming client identity certificates for any tunnel group using certificate authentication.
• This default setting can be a security risk if you are not aware of it.

Recommended Action

Disable validation-usage for unintended trustpoints. If a CA certificate is not meant to authenticate VPN peers or users, disable validation-usage for that trustpoint.

Example Configuration

trustpoint public-root-ca
 no validation-usage

Authorization Risks and Recommendations

By default, a trusted CA certificate can be used to authenticate VPN peer or user connecting to any tunnel-group. Proper authorization needs to be designed.

Recommended Action

Use certificate maps and tunnel-group maps to ensure only authorized certificates are used for specific tunnel groups. Set a default tunnel group map rule, that points to a no-access tunnel group to restrict unauthorized access.

Example Configuration

Certificate authentication is only allowed for:

• Machines with certificate issued by cn=example.com and having OU=machines in certificate subject.
• Users with certificate issued by cn=example.com and having OU=users in certificate subject.

Users with other certificates are assigned to no_access tunnel-group by default, thanks to tunnel-group-map default-group no_access command. The Certificate Map Rules have priority over group-url thanks to tunnel-group-map enable rules command. Knowing group-url does not help to bypass the Certificate Map Rules.

! Configure group-policy preventing VPN access:

group-policy no_access_gp internal
group-policy no_access_gp attributes
 banner value NO ACCESS GROUP POLICY
 (...)
 vpn-simultaneous-logins 0
!

! Configure tunnel-groups for users:

tunnel-group mgmt-tunnel type remote-access
tunnel-group mgmt-tunnel general-attributes
 address-pool vpn_pool
 default-group-policy mgmt-tunnel
tunnel-group mgmt-tunnel webvpn-attributes
 authentication certificate
 group-url https://ftd.example.com/mgmt enable
!
tunnel-group users_access type remote-access
tunnel-group users_access general-attributes
 default-group-policy user_access_gp
 address-pool vpn_pool
tunnel-group users_access webvpn-attributes
 authentication certificate
 group-url https://ftd.example.com/users enable
!

! Configure tunnel-group preventing VPN access:

tunnel-group no_access type remote-access
tunnel-group no_access general-attributes
 default-group-policy no_access_gp
 address-pool vpn_pool
tunnel-group no_access webvpn-attributes
 authentication certificate
!

! Create certificate maps for users:

crypto ca certificate map mgmt_tunnel_map 10
 issuer-name attr cn eq example.com
 subject-name attr ou eq machines
!
crypto ca certificate map users_access_map 10
 issuer-name attr cn eq example.com
 subject-name attr ou eq users
!

! Configure webvpn to use the certificate maps for tunnel-group mapping:

webvpn
 (...)
 certificate-group-map mgmt_tunnel_map 10 mgmt-tunnel
 certificate-group-map users_access_map 10 users_access
!

! Enable tunnel-group maps and set the default tunnel-group preventing access if a user certificate did not match any other certificate map:

tunnel-group-map enable rules
tunnel-group-map default-group no_access
!

Additional Resources

For more detailed configuration instructions, refer to Cisco documentation:

• Validation Usage Configuration - Cisco Secure Firewall ASA Series Command Reference, T - Z Commands
• Certificate Map Configuration - Cisco Secure Firewall ASA Series Command Reference, T - Z Commands
• Tunnel-Group Map Configuration - Cisco Secure Firewall ASA Series Command Reference, T - Z Commands
• Tunnel-Group-Map Enable Configuration - Cisco Secure Firewall ASA Series Command Reference, T - Z Commands
• Cisco ASA Software and FTD Software Trustpoint Configuration Defaults

Certificate Installation

Self-Signed Certificate Enrollment

1. (Optional) Create a named keypair with specific key size.

   Note: By default, the RSA key with the name of Default-RSA-Key and a size of 2048 is used; however, it is recommended to use a unique name for each certificate so that they do not use the same private/public keypair.

   ASAv(config)# crypto key generate rsa label SELF-SIGNED-KEYPAIR modulus 2048
   INFO: The name for the keys will be: SELF-SIGNED-KEYPAIR
   Keypair generation process begin. Please wait...

   The generated keypair can be seen with command show crypto key mypubkey rsa.

   ASAv# show crypto key mypubkey rsa
   (...)
   Key pair was generated at: 14:52:49 CEDT Jul 15 2022
   Key name: SELF-SIGNED-KEYPAIR
   Usage: General Purpose Key
   Key Size (bits): 2048
   Storage: config
   Key Data:
   
   30820122 300d0609 2a864886 f70d0101 01050003 82010f00 3082010a 02820101
   ...
   59dcd7d7 c3ee77f5 bbd0988d 515e390e b8d95177 dfaf6b94 a9df474b 1ec3b4a4
   af020301 0001

2. Create a trustpoint with a specific name. Configure enrollment type self.

   ASAv(config)# crypto ca trustpoint SELF-SIGNED
   ASAv(config-ca-trustpoint)# enrollment self

3. Configure the Fully Qualified Domain Name (FQDN) and Subject Name.

   Caution: The FQDN parameter must match the FQDN or the IP address of the ASA interface that the certificate is used for. This parameter sets the Subject Alternative Name (SAN) for the certificate.

   ASAv(config-ca-trustpoint)# fqdn asavpn.example.com
   ASAv(config-ca-trustpoint)# subject-name CN=asavpn.example.com,O=Example Inc,C=US,St=California,L=San Jose

4. (Optional) Configure keypair name created in Step 1. Not required if the default keypair is used.

   ASAv(config-ca-trustpoint)# keypair SELF-SIGNED-KEYPAIR
   ASAv(config-ca-trustpoint)# exit

5. Enroll the trustpoint and generate the certificate.

   ASAv(config)# crypto ca enroll SELF-SIGNED
   WARNING: The certificate enrollment is configured with an fqdn
   that differs from the system fqdn. If this certificate will be
   used for VPN authentication this may cause connection problems.
   
   Would you like to continue with this enrollment? [yes/no]: yes
   % The fully-qualified domain name in the certificate will be: asa.example.com
   % Include the device serial number in the subject name? [yes/no]: no
   Generate Self-Signed Certificate? [yes/no]: yes
   ASAv(config)# exit

6. Once completed, the new self-signed certificate can be seen with command show crypto ca certificates <truspoint name>.

   ASAv# show crypto ca certificates SELF-SIGNED
   Certificate
   Status: Available
   Certificate Serial Number: 62d16084
   Certificate Usage: General Purpose
   Public Key Type: RSA (2048 bits)
   Signature Algorithm: RSA-SHA256
   Issuer Name:
   unstructuredName=asa.example.com
   L=San Jose
   ST=California
   C=US
   O=Example Inc
   CN=asa.example.com
   Subject Name:
   unstructuredName=asa.example.com
   L=San Jose
   ST=California
   C=US
   O=Example Inc
   CN=asa.example.com
   Validity Date:
   start date: 15:00:58 CEDT Jul 15 2022
   end date: 15:00:58 CEDT Jul 12 2032
   Storage: config
   Associated Trustpoints: SELF-SIGNED

Enrollment By Certificate Signing Request (CSR)

1. (Optional) Create a named keypair with specific key size.

   Note: By default, the RSA key with the name of Default-RSA-Key and a size of 2048 is used; however, it is recommended to use a unique name for each certificate so that they do not use the same private/public keypair.

   ASAv(config)# crypto key generate rsa label CA-SIGNED-KEYPAIR modulus 2048
   INFO: The name for the keys will be: CA-SIGNED-KEYPAIR
   Keypair generation process begin. Please wait...

   The generated keypair can be seen with command show crypto key mypubkey rsa.

   ASAv# show crypto key mypubkey rsa
   (...)
   Key pair was generated at: 14:52:49 CEDT Jul 15 2022
   Key name: CA-SIGNED-KEYPAIR
   Usage: General Purpose Key
   Key Size (bits): 2048
   Storage: config
   Key Data:
   
   30820122 300d0609 2a864886 f70d0101 01050003 82010f00 3082010a 02820101
   ...
   59dcd7d7 c3ee77f5 bbd0988d 515e390e b8d95177 dfaf6b94 a9df474b 1ec3b4a4
   af020301 0001

2. Create a trustpoint with a specific name. Configure enrollment type terminal.

   ASAv(config)# crypto ca trustpoint CA-SIGNED
   ASAv(config-ca-trustpoint)# enrollment terminal

3. Configure the Fully Qualified Domain Name and Subject Name. The FQDN and the Subject CN parameters must match the FQDN or IP address of the service for which the certificate is used.

   ASAv(config-ca-trustpoint)# fqdn asavpn.example.com
   ASAv(config-ca-trustpoint)# subject-name CN=asavpn.example.com,O=Example Inc,C=US,St=California,L=San Jose

4. (Optional) Configure keypair name created in step 1.

   ASAv(config-ca-trustpoint)# keypair CA-SIGNED-KEYPAIR

5. (Optional) Configure certificate revocation check method - with Certificate Revocation List (CRL) or with Online Certificate Status Protocol (OCSP). By default, certificate revocation check is disabled.

   ASAv(config-ca-trustpoint)# revocation-check ocsp

6. (Optional) Authenticate the trustpoint and install the CA certificate that is going to sign the identity certificate as trusted. If not installed at this step, the CA certificate can be installed later together with identity certificate.

   ASAv(config)# crypto ca authenticate CA-SIGNED
   Enter the base 64 encoded CA certificate.
   End with the word "quit" on a line by itself
   
   ASAv(config)# crypto ca authenticate CA-SIGNED
   Enter the base 64 encoded CA certificate.
   End with the word "quit" on a line by itself
   
   -----BEGIN CERTIFICATE-----
   MIIDXDCCAkSgAwIBAgIIDM/QY/h29+kwDQYJKoZIhvcNAQELBQAwRTELMAkGA1UE
   BhMCUEwxDzANBgNVBAoTBnd3LXZwbjEMMAoGA1UECxMDbGFiMRcwFQYDVQQDEw5j
   YS5leGFtcGxlLmNvbTAeFw0xNTAyMDYxNDEwMDBaFw0zMDAyMDYxNDEwMDBaMEUx
   CzAJBgNVBAYTAlBMMQ8wDQYDVQQKEwZ3dy12cG4xDDAKBgNVBAsTA2xhYjEXMBUG
   A1UEAxMOY2EuZXhhbXBsZS5jb20wggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEK
   AoIBAQDI6pth5KFFTB29LynOg9/CTiOGYa+WFTcZXSLHZA6WTUzLYM19IbSFHWa6
   gTeBnHqToLRnQoB51QlxEA45ArL2G98aew8BMD08GXkxWayforwLA3U9WZVTZsVN
   4noWaXH1boGGD7+5vk0esJfL2B7pEhGodLh7Gki1T4KoqL/lDM9LqkzOctZkCT7f
   SkXvFik1Z1cZEGn6b2umnIqaVZ81ewIuTHOX48ls3uxTPH8+B5QG0+d1waOsbCWk
   oK5sEPpHZ3IQuVxGiirp/zmomzxl4G/tel6eyMOpjpnVtDYjQ9HNkQdQT5LKwRsX
   Oj9xKnYCbPfg3p2FdH7wJh1lK3prAgMBAAGjUDBOMAwGA1UdEwQFMAMBAf8wHQYD
   VR0OBBYEFE55kZsbra9b9tLFV52U47em9uXaMB8GA1UdIwQYMBaAFE55kZsbra9b
   9tLFV52U47em9uXaMA0GCSqGSIb3DQEBCwUAA4IBAQArsXlFwK3jlNBwOsYh5mqT
   cGqeyDMRhs3Rs/wD25M2wkAF4AYZHgN9gK9VCK+ModKMQZy4X/uhj65NDU7oFf6f
   z9kqaRijsx153jV/YLk8E9oAIatnA/fQfX6V+h74yqucfF1js3d1FjyV14odRPwM
   0jRyjalH56BFlackNc7KRddtVxYB9sfEbFhN8odlBvnUedxGAJFHqxEQKmBE+h4w
   gW8YnHOvM08svyTXSLlJf0UCdmAY+lG0gqhUlSlkFBtLRt6Z2uCot00NoMHI0hh5
   dcVcovOi/PAxnrAlJ+Ng2jrWFN3MXWZO4S3CHYMGkWqHkaHChlqDOx9badgfsyzz
   -----END CERTIFICATE-----
   
   quit
   
   INFO: Certificate has these attributes:
   Fingerprint: e9ad165c 2673424c 6e7e0c5f b30b4a02
   Do you accept this certificate? [yes/no]: yes
   WARNING: CA certificates can be used to validate VPN connections,
   by default. Please adjust the validation-usage of this
   trustpoint to limit the validation scope, if necessary.
   
   Trustpoint CA certificate accepted.
   
   % Certificate successfully imported

7. Enroll the certificate and generate a CSR that can be copied and sent to a CA for signing. The CSR includes the public key from the keypair used by trustpoint. The signed certificate can only be used by devices that have that keypair.

   Note:   CA can alter the FQDN and Subject Name parameters defined in the trustpoint when signing the CSR and creating signed identity certificate.

   ASAv(config)# crypto ca enroll CA-SIGNED
   WARNING: The certificate enrollment is configured with an fqdn
   that differs from the system fqdn. If this certificate will be
   used for VPN authentication this may cause connection problems.
   
   Would you like to continue with this enrollment? [yes/no]: yes
   % Start certificate enrollment ..
   % The subject name in the certificate will be: CN=asavpn.example.com,O=Example Inc,C=US,St=California,L=San Jose
   
   % The fully-qualified domain name in the certificate will be: asavpn.example.com
   
   % Include the device serial number in the subject name? [yes/no]: no
   
   Display Certificate Request to terminal? [yes/no]: yes
   Certificate Request follows:
   -----BEGIN CERTIFICATE REQUEST-----
   MIIDHzCCAgcCAQAwgYsxGzAZBgNVBAMMEmFzYXZwbi5leGFtcGxlLmNvbTEUMBIG
   A1UECgwLRXhhbXBsZSBJbmMxCzAJBgNVBAYTAlVTMRMwEQYDVQQIDApDYWxpZm9y
   bmlhMREwDwYDVQQHDAhTYW4gSm9zZTEhMB8GCSqGSIb3DQEJAgwSYXNhdnBuLmV4
   YW1wbGUuY29tMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA5cvZVr1j
   Me8Mz4T3vgT1Z8DAAR0avs/TBdYiqGdjyiV/3K92IIT/0r8cuAUe5rR4sjTvaXYC
   SycSbwKc4kZbr3x120ss8Itd5g4kBdrUSCprl+VMiTphQgBTAqRPk0vFX4rC8k/T
   0PFDE+2gjT1wMn9reb92jYrolGK4MWZdCzqowLPjEj5cCwu8Pv5h4hqTpudms+v4
   g3R1OODmeyv4uEMYLS/noPxZXZ8YiQMiG2EP2Bg0KOT3Fzx0mVuekonQtRhiZt+c
   zyyfSRoqyBSakEZBwABod8q1Eg5J/pH130JlitOUJEyIlFoVHqv3jL7zfA9ilInu
   NaHkir062VQNXwIDAQABoE4wDwYJKoZIhvcNAQkHMQITADA7BgkqhkiG9w0BCQ4x
   LjAsMAsGA1UdDwQEAwIFoDAdBgNVHREEFjAUghJhc2F2cG4uZXhhbXBsZS5jb20w
   DQYJKoZIhvcNAQELBQADggEBAM3Q3zvp9G3MWP7R4wkpnBOH2CNUmPENIhHNjQjH
   Yh08EOvWyoo9FaLfHKVDLvFXh0vn5osXBmPLuVps6Ta4sBRUNicRoAmmA0pDWL9z
   Duu8BQnBGuN08T/H3ydjaNoPJ/f6EZ8gXY29NXEKb/+A2Tt0VVUTsYreGS+84Gqo
   ixFOtW8R50IXg+afAVOAh81xVUFOvuAi9DsiuvufMb4wdngQSOel/B9Zgp/BfGMl
   l0ApgejACoJAGmyrn9Tj6Z/6/lbpKBKpf4VE5UXdj7WLAjw5JF/X2NrH3/cQsczi
   G2Yg2dr3WpkTIY2W/kVohTiohVRkgXOMCecUaMlYxJyLTRQ=
   -----END CERTIFICATE REQUEST-----
   
   Redisplay enrollment request? [yes/no]: no

8. Import the identity certificate. Once the CSR has been signed, an identity certificate is provided.

   ASAv(config)# crypto ca import CA-SIGNED certificate
   WARNING: The certificate enrollment is configured with an fqdn
   that differs from the system fqdn. If this certificate will be
   used for VPN authentication this may cause connection problems.

   Would you like to continue with this enrollment? [yes/no]: yes
   
   % The fully-qualified domain name in the certificate will be: asavpn.example.com
   
   Enter the base 64 encoded certificate.
   End with the word "quit" on a line by itself
   -----BEGIN CERTIFICATE-----
   MIIDoTCCAomgAwIBAgIIKbLY8Qt8N5gwDQYJKoZIhvcNAQELBQAwRTELMAkGA1UE
   BhMCUEwxDzANBgNVBAoTBnd3LXZwbjEMMAoGA1UECxMDbGFiMRcwFQYDVQQDEw5j
   (...)
   kzAihRuFqmYYUeQP2Byp/S5fNqUcyZfAczIHt8BcPmVO9l6iSF/ULGlzXMSOUX6N
   d/LHXwrcTpc1zU+7qx3TpVDZbJlwwF+BWTBlxgM0BosJx65u/n75KnbBhGUE75jV
   HX2eRzuhnnSVExCoeyed7DLiezD8
   -----END CERTIFICATE-----
   quit
   INFO: Certificate successfully imported

9. Verify the certificate chain. Once completed, the new identity certificate and the CA certificate can be seen with command show crypto ca certificates <trustpoint name>.

   ASAv# show crypto ca certificates CA-SIGNED
   CA Certificate
   Status: Available
   Certificate Serial Number: 0ccfd063f876f7e9
   Certificate Usage: General Purpose
   Public Key Type: RSA (2048 bits)
   Signature Algorithm: RSA-SHA256
   Issuer Name:
   CN=ca.example.com
   OU=lab
   O=ww-vpn
   C=PL
   Subject Name:
   CN=ca.example.com
   OU=lab
   O=ww-vpn
   C=PL
   Validity Date:
   start date: 15:10:00 CEST Feb 6 2015
   end date: 15:10:00 CEST Feb 6 2030
   Storage: config
   Associated Trustpoints: CA-SIGNED
   
   Certificate
   Status: Available
   Certificate Serial Number: 29b2d8f10b7c3798
   Certificate Usage: General Purpose
   Public Key Type: RSA (2048 bits)
   Signature Algorithm: RSA-SHA256
   Issuer Name:
   CN=ca.example.com
   OU=lab
   O=ww-vpn
   C=PL
   Subject Name:
   unstructuredName=asavpn.example.com
   L=San Jose
   ST=California
   C=US
   O=Example Inc
   CN=asavpn.example.com
   Validity Date:
   start date: 15:33:00 CEDT Jul 15 2022
   end date: 15:33:00 CEDT Jul 15 2023
   Storage: config
   Associated Trustpoints: CA-SIGNED

PKCS12 Enrollment

Enroll with the PKCS12 file that contains keypair, identity certificate, and optionally CA certificate(s) chain, received from your CA.

1. Create a trustpoint with a specific name.

   ASAv(config)# crypto ca trustpoint Trustpoint-PKCS12
   ASAv(config-ca-trustpoint)# exit

   Note:   The imported keypair is named after the trustpoint name.

2. (Optional) Configure certificate revocation check method - with Certificate Revocation List (CRL) or with Online Certificate Status Protocol (OCSP). By default, certificate revocation check is disabled.

   ASAv(config-ca-trustpoint)# revocation-check ocsp

3. Import the certificate from a PKCS12 file.

   Note:   The PKCS12 file needs to be base64 encoded. If printable characters are seen when file is opened in text editor, then it is base64 encoded. To convert a binary file to base64 encoded form openssl can be used.

   openssl enc -base64 -in asavpnpkcs12chain.example.com.pfx -out asavpnpkcs12chain.example.com.pfx.txt

   Command:

   crypto ca import trustpoint pkcs12 passphrase [ nointeractive ]

   ASAv(config)# crypto ca import TP-PKCS12 pkcs12 cisco123
   
   Enter the base 64 encoded pkcs12.
   End with the word "quit" on a line by itself:
   MIIN4gIBAzCCDawGCSqGSIb3DQEHAaCCDZ0Egg2ZMIINlTCCCBcGCSqGSIb3DQEH
   BqCCCAgwgggEAgEAMIIH/QYJKoZIhvcNAQcBMBwGCiqGSIb3DQEMAQMwDgQIiK0c
   wqE3Tm0CAggAgIIH0NjxmJBuoPRuYl1VxTiawHzsL8kIl03lOj7tcWmECBwzsKKq
   (...)
   PXowMwYJKoZIhvcNAQkUMSYeJABhAHMAYQB2AHAAbgAuAGUAeABhAG0AcABsAGUA
   LgBjAG8AbTAtMCEwCQYFKw4DAhoFAAQUPXZZtBeqlh98wQljHW7J/hqoKcwECD05
   dnxCNJx6
   quit
   
   Trustpoint CA certificate accepted.
   WARNING: CA certificates can be used to validate VPN connections,
   by default. Please adjust the validation-usage of this
   trustpoint to limit the validation scope, if necessary.
   
   INFO: Import PKCS12 operation completed successfully.
   

4. Verify the installed certificate(s).

   ASAv# show crypto ca certificates TP-PKCS12
   
   Certificate
   Status: Available
   Certificate Serial Number: 2b368f75e1770fd0
   Certificate Usage: General Purpose
   Public Key Type: RSA (2048 bits)
   Signature Algorithm: RSA-SHA256
   Issuer Name:
   CN=ca.example.com
   OU=lab
   O=ww-vpn
   C=PL
   Subject Name:
   unstructuredName=asavpn.example.com
   CN=asavpnpkcs12chain.example.com
   O=Example Inc
   L=San Jose
   ST=California
   C=US
   Validity Date:
   start date: 15:33:00 CEDT Jul 15 2022
   end date: 15:33:00 CEDT Jul 15 2023
   Storage: config
   Associated Trustpoints: TP-PKCS12
   
   CA Certificate
   Status: Available
   Certificate Serial Number: 0ccfd063f876f7e9
   Certificate Usage: General Purpose
   Public Key Type: RSA (2048 bits)
   Signature Algorithm: RSA-SHA256
   Issuer Name:
   CN=ca.example.com
   OU=lab
   O=ww-vpn
   C=PL
   Subject Name:
   CN=ca.example.com
   OU=lab
   O=ww-vpn
   C=PL
   Validity Date:
   start date: 15:10:00 CEST Feb 6 2015
   end date: 15:10:00 CEST Feb 6 2030
   Storage: config
   Associated Trustpoints: TP-PKCS12

   In the previous example, the PKCS12 contained the identity and CA certificate - the two entries - Certificate and CA Certificate. Otherwise, only Certificate is present.

5. (Optional) Authenticate the trustpoint.

   If the PKCS12 did not contain the CA certificate, and the CA certificate was obtained separately in PEM format, then it can be installed manually.

   ASAv(config)# crypto ca authenticate TP-PKCS12
   Enter the base 64 encoded CA certificate.
   End with the word "quit" on a line by itself
   
   -----BEGIN CERTIFICATE-----
   MIIDXDCCAkSgAwIBAgIIDM/QY/h29+kwDQYJKoZIhvcNAQELBQAwRTELMAkGA1UE
   BhMCUEwxDzANBgNVBAoTBnd3LXZwbjEMMAoGA1UECxMDbGFiMRcwFQYDVQQDEw5j
   (...)
   gW8YnHOvM08svyTXSLlJf0UCdmAY+lG0gqhUlSlkFBtLRt6Z2uCot00NoMHI0hh5
   dcVcovOi/PAxnrAlJ+Ng2jrWFN3MXWZO4S3CHYMGkWqHkaHChlqDOx9badgfsyzz
   -----END CERTIFICATE-----
   quit
   
   INFO: Certificate has these attributes:
   Fingerprint: e9ad165c 2673424c 6e7e0c5f b30b4a02
   Do you accept this certificate? [yes/no]: yes
   
   WARNING: CA certificates can be used to validate VPN connections,
   by default. Please adjust the validation-usage of this
   trustpoint to limit the validation scope, if necessary.
   
   Trustpoint CA certificate accepted.
   
   % Certificate successfully imported
   

Certificate Renewal

Renew Self-Signed Certificate

1. Check the current certificate expiry date.

   # show crypto ca certificates SELF-SIGNED
   Certificate
   Status: Available
   Certificate Serial Number: 62d16084
   Certificate Usage: General Purpose
   Public Key Type: RSA (2048 bits)
   Signature Algorithm: RSA-SHA256
   Issuer Name:
   unstructuredName=asa.example.com
   L=San Jose
   ST=California
   C=US
   O=Example Inc
   CN=asa.example.com
   Subject Name:
   unstructuredName=asa.example.com
   L=San Jose
   ST=California
   C=US
   O=Example Inc
   CN=asa.example.com
   Validity Date:
   start date: 15:00:58 CEDT Jul 15 2022
   end date: 15:00:58 CEDT Jul 12 2032
   Storage: config
   Associated Trustpoints: SELF-SIGNED

2. Regenerate the certificate.

   ASAv# conf t
   ASAv(config)# crypto ca enroll SELF-SIGNED
   WARNING: The certificate enrollment is configured with an fqdn
   that differs from the system fqdn. If this certificate will be
   used for VPN authentication this may cause connection problems.
   Would you like to continue with this enrollment? [yes/no]: yes
   
   WARNING: Trustpoint TP has already enrolled and has
   a device cert issued to it.
   If you successfully re-enroll this trustpoint,
   the current certificate will be replaced.
   Do you want to continue with re-enrollment? [yes/no]: yes
   % The fully-qualified domain name in the certificate will be: asa.example.com
   % Include the device serial number in the subject name? [yes/no]: no
   Generate Self-Signed Certificate? [yes/no]: yes
   ASAv(config)# exit
   

3. Verify the new certificate.

   ASAv# show crypto ca certificates SELF-SIGNED
   Certificate
   Status: Available
   Certificate Serial Number: 62d16085
   Certificate Usage: General Purpose
   Public Key Type: RSA (2048 bits)
   Signature Algorithm: RSA-SHA256
   Issuer Name:
   unstructuredName=asa.example.com
   L=San Jose
   ST=California
   C=US
   O=Example Inc
   CN=asa.example.com
   Subject Name:
   unstructuredName=asa.example.com
   L=San Jose
   ST=California
   C=US
   O=Example Inc
   CN=asa.example.com
   Validity Date:
   start date: 15:09:09 CEDT Jul 20 2022
   end date: 15:09:09 CEDT Jul 17 2032
   Storage: config
   Associated Trustpoints: SELF-SIGNED
   

Renew Certificate Enrolled with Certificate Signing Request (CSR)

Note: If any of the new certificate elements (subject/fqdn, keypair) need to be changed for the new certificate, then create a new certificate. Refer to Enrollment using Certificate Signing Request (CSR) section. The next procedure just refreshes the certificate expiry date.

1. Check the current certificate expiry date.

   ASAv# show crypto ca certificates CA-SIGNED
   
   Certificate
   Status: Available
   Certificate Serial Number: 29b2d8f10b7c3798
   Certificate Usage: General Purpose
   Public Key Type: RSA (2048 bits)
   Signature Algorithm: RSA-SHA256
   Issuer Name:
   CN=ca.example.com
   OU=lab
   O=ww-vpn
   C=PL
   Subject Name:
   unstructuredName=asavpn.example.com
   L=San Jose
   ST=California
   C=US
   O=Example Inc
   CN=asavpn.example.com
   Validity Date:
   start date: 15:33:00 CEDT Jul 15 2022
   end date: 15:33:00 CEDT Jul 15 2023
   Storage: config
   Associated Trustpoints: CA-SIGNED
   
   Certificate
   Subject Name:
   Status: Pending terminal enrollment
   Key Usage: General Purpose
   Fingerprint: 790aa617 c30c6894 0bdc0327 0d60b032
   Associated Trustpoint: CA-SIGNED
   

2. Enroll the certificate. Generate a CSR that can be copied and sent to a CA for signing. The CSR includes the public key from the keypair used by trustpoint - the signed certificate can only be used by devices that have that keypair.

   Note: CA can alter the FQDN and Subject Name parameters defined in the trustpoint when signing the CSR and creating signed identity certificate.

   Note: For the same Trustpoint, with no changed subject/fqdn and keypair configuration, subsequent enrollments give the same CSR as the initial one.

   ASAv# conf t
   ASAv(config)# crypto ca enroll CA-SIGNED
   
   WARNING: The certificate enrollment is configured with an fqdn
   that differs from the system fqdn. If this certificate will be
   used for VPN authentication this may cause connection problems.
   Would you like to continue with this enrollment? [yes/no]: yes
   
   % Start certificate enrollment ..
   % The subject name in the certificate will be: CN=asavpn.example.com,O=Example Inc,C=US,St=California,L=San Jose
   % The fully-qualified domain name in the certificate will be: asavpn.example.com
   % Include the device serial number in the subject name? [yes/no]: no
   Display Certificate Request to terminal? [yes/no]: yes
   Certificate Request follows:
   
   -----BEGIN CERTIFICATE REQUEST-----
   MIIDHzCCAgcCAQAwgYsxGzAZBgNVBAMMEmFzYXZwbi5leGFtcGxlLmNvbTEUMBIG
   A1UECgwLRXhhbXBsZSBJbmMxCzAJBgNVBAYTAlVTMRMwEQYDVQQIDApDYWxpZm9y
   bmlhMREwDwYDVQQHDAhTYW4gSm9zZTEhMB8GCSqGSIb3DQEJAgwSYXNhdnBuLmV4
   YW1wbGUuY29tMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA5cvZVr1j
   Me8Mz4T3vgT1Z8DAAR0avs/TBdYiqGdjyiV/3K92IIT/0r8cuAUe5rR4sjTvaXYC
   SycSbwKc4kZbr3x120ss8Itd5g4kBdrUSCprl+VMiTphQgBTAqRPk0vFX4rC8k/T
   0PFDE+2gjT1wMn9reb92jYrolGK4MWZdCzqowLPjEj5cCwu8Pv5h4hqTpudms+v4
   g3R1OODmeyv4uEMYLS/noPxZXZ8YiQMiG2EP2Bg0KOT3Fzx0mVuekonQtRhiZt+c
   zyyfSRoqyBSakEZBwABod8q1Eg5J/pH130JlitOUJEyIlFoVHqv3jL7zfA9ilInu
   NaHkir062VQNXwIDAQABoE4wDwYJKoZIhvcNAQkHMQITADA7BgkqhkiG9w0BCQ4x
   LjAsMAsGA1UdDwQEAwIFoDAdBgNVHREEFjAUghJhc2F2cG4uZXhhbXBsZS5jb20w
   DQYJKoZIhvcNAQELBQADggEBAM3Q3zvp9G3MWP7R4wkpnBOH2CNUmPENIhHNjQjH
   Yh08EOvWyoo9FaLfHKVDLvFXh0vn5osXBmPLuVps6Ta4sBRUNicRoAmmA0pDWL9z
   Duu8BQnBGuN08T/H3ydjaNoPJ/f6EZ8gXY29NXEKb/+A2Tt0VVUTsYreGS+84Gqo
   ixFOtW8R50IXg+afAVOAh81xVUFOvuAi9DsiuvufMb4wdngQSOel/B9Zgp/BfGMl
   l0ApgejACoJAGmyrn9Tj6Z/6/lbpKBKpf4VE5UXdj7WLAjw5JF/X2NrH3/cQsczi
   G2Yg2dr3WpkTIY2W/kVohTiohVRkgXOMCecUaMlYxJyLTRQ=
   -----END CERTIFICATE REQUEST-----
   
   Redisplay enrollment request? [yes/no]: no
   

3. Import the identity certificate. Once the CSR has been signed, an identity certificate is provided.

   ASAv(config)# crypto ca import CA-SIGNED certificate
   
   WARNING: The certificate enrollment is configured with an fqdn
   that differs from the system fqdn. If this certificate will be
   used for VPN authentication this may cause connection problems.
   Would you like to continue with this enrollment? [yes/no]: yes
   
   % The fully-qualified domain name in the certificate will be: asavpn.example.com
   
   Enter the base 64 encoded certificate.
   End with the word "quit" on a line by itself
   
   -----BEGIN CERTIFICATE-----
   MIIDgTCCAmmgAwIBAgIIMA+aIxCtNtMwDQYJKoZIhvcNAQELBQAwRTELMAkGA1UE
   BhMCUEwxDzANBgNVBAoTBnd3LXZwbjEMMAoGA1UECxMDbGFiMRcwFQYDVQQDEw5j
   YS5leGFtcGxlLmNvbTAeFw0yMjA3MjAxNDA5MDBaFw0yMzA3MjAxNDA5MDBaMIGL
   MRswGQYDVQQDDBJhc2F2cG4uZXhhbXBsZS5jb20xFDASBgNVBAoMC0V4YW1wbGUg
   SW5jMQswCQYDVQQGEwJVUzETMBEGA1UECAwKQ2FsaWZvcm5pYTERMA8GA1UEBwwI
   U2FuIEpvc2UxITAfBgkqhkiG9w0BCQIMEmFzYXZwbi5leGFtcGxlLmNvbTCCASIw
   DQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAOXL2Va9YzHvDM+E974E9WfAwAEd
   Gr7P0wXWIqhnY8olf9yvdiCE/9K/HLgFHua0eLI072l2AksnEm8CnOJGW698ddtL
   LPCLXeYOJAXa1Egqa5flTIk6YUIAUwKkT5NLxV+KwvJP09DxQxPtoI09cDJ/a3m/
   do2K6JRiuDFmXQs6qMCz4xI+XAsLvD7+YeIak6bnZrPr+IN0dTjg5nsr+LhDGC0v
   56D8WV2fGIkDIhthD9gYNCjk9xc8dJlbnpKJ0LUYYmbfnM8sn0kaKsgUmpBGQcAA
   aHfKtRIOSf6R9d9CZYrTlCRMiJRaFR6r94y+83wPYpSJ7jWh5Iq9OtlUDV8CAwEA
   AaMuMCwwCwYDVR0PBAQDAgWgMB0GA1UdEQQWMBSCEmFzYXZwbi5leGFtcGxlLmNv
   bTANBgkqhkiG9w0BAQsFAAOCAQEAfQUchY4UjhjkySMJAh7NT3TT5JJ4NzqW8qHa
   wNq+YyHR+sQ6G3vn+6cYCU87tqWlY3fXC27TwweREwMbq8NsJrr80hsChYby8kwE
   LnTkrN7dJBl7u5OVQ3DRjfmFrJ9LEUaYZx1HYvcS1kAeEeVB4VJwVzeujWepcmEM
   p7cB6veTcF9rulDVRImd0KYEOx+HYav2INT2udc0G1yDwml/mqdf0/ON2SpBBpnE
   gtiKshtsST/NAw25WjkrDIfN8uR2z5xpzxnEDUBoHOipGlgb1I6G1ARXWO+LwfBl
   n1QD5b/RdQOUbLCpfKNPdE/9wNnoXGDlJ7qfZxrO4T7ld2Idug==
   -----END CERTIFICATE-----
   quit
   
   INFO: Certificate successfully imported

4. Verify the new certificate expiry date.

   ASAv# show crypto ca certificates CA-SIGNED
   Certificate
   Status: Available
   Certificate Serial Number: 300f9a2310ad36d3
   Certificate Usage: General Purpose
   Public Key Type: RSA (2048 bits)
   Signature Algorithm: RSA-SHA256
   Issuer Name:
   CN=ca.example.com
   OU=lab
   O=ww-vpn
   C=PL
   Subject Name:
   unstructuredName=asavpn.example.com
   L=San Jose
   ST=California
   C=US
   O=Example Inc
   CN=asavpn.example.com
   Validity Date:
   start date: 16:09:00 CEDT Jul 20 2022
   end date: 16:09:00 CEDT Jul 20 2023
   Storage: config
   Associated Trustpoints: CA-SIGNED
   

PKCS12 Renewal

It is not possible to renew a certificate in trustpoint enrolled using PKCS12 file. To install a new certificate, a new trustpoint needs to be created.

1. Create a trustpoint with a specific name.

   ASAv(config)# crypto ca trustpoint Trustpoint-PKCS12-2022
   ASAv(config-ca-trustpoint)# exit

2. (Optional) Configure certificate revocation check method - with Certificate Revocation List (CRL) or with Online Certificate Status Protocol (OCSP). By default, certificate revocation check is disabled.

   ASAv(config-ca-trustpoint)# revocation-check ocsp

3. Import the new certificate from a PKCS12 file.

   Note:   The PKCS12 file needs to be base64 encoded. If printable characters are seen when file is opened in text editor, then it is base64 encoded. To convert a binary file to base64 encoded form, openssl can be used.

   openssl enc -base64 -in asavpnpkcs12chain.example.com.pfx -out asavpnpkcs12chain.example.com.pfx.txt

   ASAv(config)# crypto ca import TP-PKCS12-2022 pkcs12 cisco123
   
   Enter the base 64 encoded pkcs12.
   End with the word "quit" on a line by itself:
   MIIN4gIBAzCCDawGCSqGSIb3DQEHAaCCDZ0Egg2ZMIINlTCCCBcGCSqGSIb3DQEH
   BqCCCAgwgggEAgEAMIIH/QYJKoZIhvcNAQcBMBwGCiqGSIb3DQEMAQMwDgQIiK0c
   wqE3Tm0CAggAgIIH0NjxmJBuoPRuYl1VxTiawHzsL8kIl03lOj7tcWmECBwzsKKq
   (...)
   PXowMwYJKoZIhvcNAQkUMSYeJABhAHMAYQB2AHAAbgAuAGUAeABhAG0AcABsAGUA
   LgBjAG8AbTAtMCEwCQYFKw4DAhoFAAQUPXZZtBeqlh98wQljHW7J/hqoKcwECD05
   dnxCNJx6
   quit
   
   Trustpoint CA certificate accepted.
   WARNING: CA certificates can be used to validate VPN connections,
   by default. Please adjust the validation-usage of this
   trustpoint to limit the validation scope, if necessary.
   
   INFO: Import PKCS12 operation completed successfully.
   

   Note:   If the new PKCS12 file contains an identity certificate with the same keypair that was used with the old certificate, the new trustpoint refers to old keypair name.
   Example:

   ASAv(config)# crypto ca import TP-PKCS12-2022 pkcs12 cisco123
   
   Enter the base 64 encoded pkcs12. End with the word "quit" on a line by itself:
   
   MIIN4gIBAzCCDawGCSqGSIb3DQEHAaCCDZ0Egg2ZMIINlTCCCBcGCSqGSIb3DQEH
   ...
   dnxCNJx6
   quit
   
   WARNING: Identical public key already exists as TP-PKCS12
   
   ASAv(config)# show run crypto ca trustpoint TP-PKCS12-2022
   crypto ca trustpoint TP-PKCS12-2022
    keypair TP-PKCS12
    no validation-usage crl configure
   

4. Verify the installed certificate(s).

   ASAv# show crypto ca certificates TP-PKCS12-2022
   
   Certificate
    Status: Available 
    Certificate Serial Number: 2b368f75e1770fd0
    Certificate Usage: General Purpose
    Public Key Type: RSA (2048 bits)
    Signature Algorithm: RSA-SHA256
    Issuer Name: CN=ca.example.com OU=lab O=ww-vpn C=PL
    Subject Name: unstructuredName=asavpn.example.com CN=asavpnpkcs12chain.example.com O=Example Inc L=San Jose ST=California C=US
    Validity Date:
    start date: 15:33:00 CEDT Jul 15 2022
    end date: 15:33:00 CEDT Jul 15 2023
    Storage: config
    Associated Trustpoints: TP-PKCS12-2022
   
   CA Certificate
    Status: Available
    Certificate Serial Number: 0ccfd063f876f7e9
    Certificate Usage: General Purpose
    Public Key Type: RSA (2048 bits)
    Signature Algorithm: RSA-SHA256 
    Issuer Name: CN=ca.example.com OU=lab O=ww-vpn C=PL
    Subject Name: CN=ca.example.com OU=lab O=ww-vpn C=PL
    Validity Date:
    start date: 15:10:00 CEST Feb 6 2015
    end date: 15:10:00 CEST Feb 6 2030
    Storage: config
    Associated Trustpoints: TP-PKCS12-2022
   

   In the previous example, the PKCS12 contained the identity certificate and the CA certificate, therefore, two entries are seen after the import: Certificate and CA Certificate. Otherwise, only Certificate entry is present.

5. (Optional) Authenticate the trustpoint.

   If the PKCS12 did not contain the CA certificate, and the CA certificate was obtained separately in PEM format, then it can be installed manually.

   ASAv(config)# crypto ca authenticate TP-PKCS12-2022
   Enter the base 64 encoded CA certificate.
   End with the word "quit" on a line by itself
   
   -----BEGIN CERTIFICATE-----
   MIIDXDCCAkSgAwIBAgIIDM/QY/h29+kwDQYJKoZIhvcNAQELBQAwRTELMAkGA1UE
   BhMCUEwxDzANBgNVBAoTBnd3LXZwbjEMMAoGA1UECxMDbGFiMRcwFQYDVQQDEw5j
   (...)
   gW8YnHOvM08svyTXSLlJf0UCdmAY+lG0gqhUlSlkFBtLRt6Z2uCot00NoMHI0hh5
   dcVcovOi/PAxnrAlJ+Ng2jrWFN3MXWZO4S3CHYMGkWqHkaHChlqDOx9badgfsyzz
   -----END CERTIFICATE-----
   quit
   
   INFO: Certificate has these attributes:
   Fingerprint: e9ad165c 2673424c 6e7e0c5f b30b4a02
   Do you accept this certificate? [yes/no]: yes
   
   WARNING: CA certificates can be used to validate VPN connections,
   by default. Please adjust the validation-usage of this
   trustpoint to limit the validation scope, if necessary.
   
   Trustpoint CA certificate accepted.
   
   % Certificate successfully imported
   

6. Reconfigure the ASA to use the new trustpoint instead of the old one.

Example:

ASAv# show running-config ssl trust-point 
ssl trust-point TP-PKCS12
ASAv# conf t
ASAv(config)#ssl trust-point TP-PKCS12-2022
ASAv(config)#exit

Note: A trustpoint can be used in different configuration elements. Check your configuration where the old trustpoint is used.

Related Information

How to configure time settings on an ASA.

Check this reference for the steps required to set up the time and date correctly on the ASA. CLI Book 1: Cisco Secure Firewall ASA Series General Operations CLI Configuration Guide, 9.18