One Identity Safeguard for Privileged Sessions (SPS) can check the validity of certificates using the certificates and certificate-revocation lists of the certificate authorities that issued the certificates. This can be used for example to verify the certificates of the servers in SSH/RDP connections.

To create a list of CA certificates to use during the certificate validation

Navigate to Policies > Trusted CA Lists and click to create a new list.

Figure 186: Policies > Trusted CA Lists — Creating trusted CA lists
Enter a name for the CA list into the topmost field.
Click in the Certificate field, and upload the certificate of the Certificate Authority (CA) that will be used to validate the certificates.

Enter the URL of the Certificate Revocation List of the CA into the CRL field. Certificates appearing on the CRL list will be automatically rejected.

NOTE: Note that only X.509 CRLs are accepted in either PEM and DER format. PKCS7 CRLs are not accepted.

Caution:

From SPS version 6.5.0, SPS verifies the signature and the expiration on the Certificate Revocation Lists (CRL) configured at Policies > Trusted CA Lists. The CRLs must be signed by the same Certificate Authority for which it was uploaded. If the validation of the remote CRL fails (or when the remote CRL is unavailable), an alert is generated. Despite the alert, SPS still updates the active CRL with the remote CRL unless the previously downloaded CRL local copy is still valid. Note that it is a security issue if it is not possible to validate the signature on the CRL. If the local copy of the CRL expires, connections that rely on the Trusted CA may fail.

In conjunction with this change, if the remote CRL is specified as a HTTPS URL, the web server certificate is no longer verified before the download.

CRL refresh is implemented as a background service running hourly. Therefore if the problem with the remote CRL persists, you may get alerts every hour.

To further limit which certificates are accepted, you may use the following options:
- Strict hostname check: Select this option to accept only certificates when the Common Name of the certificate contains the hostname or the IP address of the host showing the certificate.
- Use DNS to lookup hostnames: Select this option to use the domain name server set on Basic Settings > Network > Naming to resolve the hostnames and IP addresses for certificate validation. If you have enabled the Strict hostname check option, you probably want to enable this option as well.
- To restrict the accepted certificates based on the content of the certificate, enter the required value into the appropriate field of the User certificate validation section. For example, to accept only certificates that contain Example Inc. in their Organization Name field, enter Example Inc. in to the Organization Name field. In the Common name, E-mail address, and Alternative e-mail address fields you can use the $username macro to refer to the username used in the connection. This macro makes it possible to check that the user is using his own certificate.
Click .

Verifying certificates with Certificate Authorities using trust stores

General connection settings > Verifying certificates with Certificate Authorities using trust stores

One Identity Safeguard for Privileged Sessions (SPS) can check the validity of certificates using the certificates and certificate revocation lists of the certificate authorities (CA) that issued the certificates. This can be used to verify the certificates of the servers in TLS connections.

Trust stores serve as local certificate storages where you can store the certificate chains of trusted CAs. Create and configure custom trust stores to verify the certificates in TLS connections. Note that you cannot modify the built-in trust store, which contains common CA certificates that the operational system of SPS uses.

You can use custom trust stores in the following locations:

Basic Settings > Management > Syslog — Check server certificate. For more information, see Configuring system logging.
Basic Settings > Management > Universal SIEM forwarder — TLS with certificate validation. For more information, see Using the universal SIEM forwarder.
Users & Access Control > Settings > Authentication settings — Configuring X.509 authentication. For more information, see Authenticating users with X.509 certificates.
Users & Access Control > Settings > Authentication settings — Configuring LDAP, TLS and STARTLS encryption method. For more information, see Managing One Identity Safeguard for Privileged Sessions (SPS) users from an LDAP database.
Policies > LDAP Servers — Configuring encryption. For more information, see Authenticating users to an LDAP server.

Prerequisites

To specify cipher settings and version requirements that SPS uses for establishing TLS connections in the Cryptography Settings section, navigate to Basic Settings > Trust Stores.

Figure 187: Basic Settings > Trust Stores — Cryptography settings

Cipher strength specifies the cipher string OpenSSL will use. The following settings options are possible:

Recommended: this setting only uses ciphers with adequate security level.
Custom: this setting allows you to specify the list of ciphers you want to permit SPS to use in the connection. This setting is only recommended to ensure compatibility with older systems. For more details on customizing this list, check the 'openssl-ciphers' manual page on your SPS appliance.

For example: ALL:!aNULL:@STRENGTH

Minimum TLS version specifies the minimal TLS version SPS will offer during negotiation. The following settings options are possible:

TLS 1.2: this setting only offers TLS version 1.2 during the negotiation. This is the recommended setting.
TLS 1.1: this setting offers TLS version 1.1 and later versions during the negotiation.
TLS 1.0: this setting offers TLS version 1.0 and later versions during the negotiation.

Maximum TLS version specifies the maximal TLS version SPS will offer during negotiation. The following settings options are possible:

TLS 1.2: this setting will only offer TLS version 1.2 during negotiation. This is the recommended setting.
TLS 1.1: this setting will offer TLS version 1.1 and later versions during negotiation.
TLS 1.0: this setting will offer TLS version 1.0 and later versions during negotiation.
Latest: this setting will offer the latest TLS version during negotiation.

NOTE: Note that SPS only permits TLS-encrypted connections. SSLv3 is not supported.

To create a custom trust store or edit an existing custom trust store

Navigate to Basic Settings > Trust Stores.

Figure 188: Basic Settings > Trust Stores
In the Custom trust stores section, click Add new Trust Store. To change the settings of an existing trust store, click Edit.

The Add new trust store or Edit trust store window opens.

Figure 189: Basic Settings > Trust Stores — Add new trust store
In the Trust Store Name field, enter a name for the trust store. For example, ts1.
To add the certificate of the CA to the trust store that will be used to validate the certificates, click Add certificate. The Add certificate window opens.
Paste or drag the PEM certificate file to the Key content field. You can also click Browse to navigate to the PEM certificate file on your computer.

Figure 190: Basic Settings > Trust Stores — Add certificate
- You must upload all the CA certificates from the users' certificate chains (including the root CA). Therefore, these CA certificates must be on your computer in PEM format.
- The certificates of the users must contain the user name used to authenticate on SPS. You must know which certificate field will contain the user names (for example, CN or UID).
- The certificates must be imported into the browsers of the users. With SPS, you can authenticate with a certificate only if a personal certificate is available in the browser.
NOTE:

You can only upload a single PEM certificate.

You cannot upload multiple PEM certificates in a single file.

To upload more PEM certificates, add them as single entities one by one.
Click Add.
Set the revocation check type for the trust store.
- None: Do not check certificate revocation status.
- Leaf: Check the revocation status of the peer's certificate, but do not check the revocation status of the CA certificates in the chain.
- Full: Check the revocation status of the peer's certificate and all CA certificates in the chain.
If you set the revocation check type to Leaf or Full, click Add new CRL URL to specify the CRL distribution point(s) of the CA that issued the peers' certificates.
1. Enter the URL of the Certificate Revocation List (CRL) of the CA into the CRL URL field. Certificates appearing on the CRL list will be automatically rejected.
2. To remove a CRL distribution point from the trust store, click Remove.
Click Save and close the window.
To delete a certificate from a trust store, click Edit to open the Edit trust store window, click on the certificate, and click Delete.
To delete a trust store, click Edit to open the Edit trust store window, and click Delete.
Click .

Signing certificates on-the-fly

General connection settings > Signing certificates on-the-fly

At a number of places, One Identity Safeguard for Privileged Sessions (SPS) can generate the server certificates on the fly. This technique is used for example in SSL-encrypted RDP sessions, RDP sessions that use Network Level Authentication (CredSSP), or SSH connections that use X.509-based authentication.

NOTE: Note the following points about using signing CAs:

Signing CAs require a CA certificate permitted to sign certificates, and also the corresponding private key.
These CAs cannot be used to sign audit trails. For details on how to configure the certificates used to sign audit trails, see Digitally signing audit trails.
The version of the generated certificates will be the same as the version of the signing CA.
SPS ignores the CRL (from the crlDistributionPoints extension) of the signing CA when generating certificates. If you want to include a CRL in the generated certificates, you must set it manually. See the following steps for details.

To create a signing CA using the built-in signing CA solution

Navigate to Policies > Signing CAs and click .
Select Local.
Enter a name for the CA into the topmost field.

Figure 191: Policies > Signing CAs — Creating Signing CAs - Local
To upload a CA certificate and its private key, complete the following steps. Skip this step if you want to generate a CA on SPS.
1. Click Edit in the CA X.509 certificate field and upload the certificate of the certificate authority. Alternatively, you can upload a certificate chain, where one member of the chain is the CA that will sign the certificates.
2. Click Edit in the CA private key field and upload the private key of the certificate authority that will sign the certificates.
3. (Optional) Enter the URL of the Certificate Revocation List (CRL) that you generated using your Certificate Authority in your Public Key Infrastructure (PKI) solution. The URL pointing to this CRL will be included in the certificate. This is the CRL information that will be shown to clients connecting to SPS.
  
  Note that the CRL list is not generated by the internal CA of SPS. The list must come from your own PKI solution.
4. Click .
To generate a CA certificate on SPS, complete the following steps:
1. Enter the Common Name for the CA certificate into the Common Name field. This name will be visible in the Issued By field of the certificates signed by this CA.
2. Fill the other fields as required, then click Generate private key and certificate.
3. Click .

To create a signing CA using an external signing CA plugin

Navigate to Policies > Signing CAs and click .
Select External Plugin.
Enter a name for the CA into the topmost field.

Figure 192: Policies > Signing CAs — Creating Signing CAs - External Plugin
From the Plugin field, select an uploaded external plugin using the drop-down menu.

To be able to select from the drop-down menu, you must have an external plugin uploaded in Basic Settings > Plugins.

For more information about how to create an external Signing CA plugin, see Creating an external Signing CA.
Optionally, fill the Configuration field as required by the uploaded plugin.

The input you enter in the Configuration field is passed down to the plugin.

Creating an external Signing CA

General connection settings > Signing certificates on-the-fly > Creating an external Signing CA

Overview

The External Signing CA plugin's purpose is to generate certificate and private key pairs signed by a Certificate Authority. By using this type of plugin the certificate signing can be tailored to fit any custom requirement.

Details

The plugin is a .zip file containing a MANIFEST and a main.py file.

The MANIFEST file

The MANIFEST file is a YAML file, and should conform to version 1.2 of the YAML specification. It should contain the following information about the plugin:

api: 1.0
type: signingca
name: MySigningCaPlugin
version: 1.0
description: My custom Signing CA

The type of the plugin must be signingca.

The main.py file

A Plugin class containing the following methods must be defined in the main.py file:

generate_for_addresses: generates a key/certificate pair for the given addresses (IP/DNS)
generate_for_username: generates a key/certificate pair for the given username
generate_for_subject: generates a key/certificate pair for the given subject values

Method arguments

Each method must take the following arguments:

generate_for_addresses:
- addresses: {list of str} - contains either IP or DNS addresses for which the certificate shall be issued
- keytype: {str} - contains a fixed value of 'RSA' or 'DSS' indicating the requested key type for the certificate
generate_for_username:
- username {str} - contains the username for which the certificate shall be issued
- keytype: {str} - contains a fixed value of 'RSA' or 'DSS' indicating the requested key type for the certificate
generate_for_subject:
- subject {list of (str, str)} - contains the certificate subject as type-value pairs (tuples). Valid types are the following:
  - 'C' country name
  - 'ST' state or province name
  - 'L' locality name
  - 'O' orangization name
  - 'OU' organizational unit
  - 'CN' common name
  - 'emailAddress' email address
- keytype: {str} - contains a fixed value of 'RSA' or 'DSS' indicating the requested key type for the certificate

Method return values

Each method returns a {dict} that must have the following keys:

key: {str} the generated key
chain: {list of str} a PEM encoded certificate chain containing the generated certificate as the first element

Example

The code below demonstrates a simple plugin that can sign certificates with a built in CA. By default it uses a pre-generated CA certificate and key to complete signing requests. To use a custom certificate, provide a certificate and a key in a python dict format in the configuration field.

NOTE: If you wish to try this sample code, you will need to provide a MANIFEST file (see below) and the following package dependencies in the .zip file alongside the plugin:

asn1crypto
certbuilder
oscrypto

main.py:

#!/usr/bin/env pluginwrapper3

#
# Copyright (c) One Identity
# All Rights Reserved.
#

from ast import literal_eval
from certbuilder import CertificateBuilder, pem_armor_certificate
from ipaddress import ip_address
from oscrypto import asymmetric

class Plugin(object):

    plugin_root_ca = """-----BEGIN CERTIFICATE-----
MIIDhjCCAm6gAwIBAgIIW+mOlk1Cu4swDQYJKoZIhvcNAQELBQAwYTELMAkGA1UE
BhMCSFUxETAPBgNVBAgMCEJ1ZGFwZXN0MREwDwYDVQQHDAhCdWRhcGVzdDEQMA4G
A1UECgwHQmFsYWJpdDEaMBgGA1UEAwwRQmFsYWJpdCBQbHVnaW4gQ0EwHhcNMTgx
MTEyMTQzMDQ2WhcNMTkxMTEyMTQzMDQ2WjBhMQswCQYDVQQGEwJIVTERMA8GA1UE
CAwIQnVkYXBlc3QxETAPBgNVBAcMCEJ1ZGFwZXN0MRAwDgYDVQQKDAdCYWxhYml0
MRowGAYDVQQDDBFCYWxhYml0IFBsdWdpbiBDQTCCASIwDQYJKoZIhvcNAQEBBQAD
ggEPADCCAQoCggEBAO73W0ONVwIaBJas+qUe0VBZ4rtk6PtzRNenZcBkTCkITuuF
DAQ3T1qLUsCyQ4uHMo+yKZUqR3HxbWGxS2l4IaHP6Hbna2kNEyYEsg16mGVUz6tc
D6bxFu3EpB7eU/OXh8RS8URIfZbLNrql1sKe7k1hpXUDS74Ra/avUIYKIpZ5sCjs
F6MBZWz5u3tNUa53xVmqgpnQ6pozN+OQ6k74DjK4xqWqJgTWcN6rxZ9k2voQYE3s
H66jl53q+Zl0D4w/AEW5W3OYNHJtx3tsc36sD2i0doqBCAAvflcSDEs7TXhfXSkC
qCBKyx8ics5EL9h49MDPGwDTehzwvXusz8LlxeMCAwEAAaNCMEAwDwYDVR0TAQH/
BAUwAwEB/zAdBgNVHQ4EFgQUyFWUMJli0q5CtJOp25IqK2M70oAwDgYDVR0PAQH/
BAQDAgEGMA0GCSqGSIb3DQEBCwUAA4IBAQCWoQCJPqfM4Sjg0R2O42yrE2GtQsXf
Qb3Dur+CefWLcvjI28t1xuj31khDgpNTwk4IVYrvarNX33C3tjYKgcimwWRMijbA
p8kZzFajOZSWC32CQtkWL79LLkJCTJB7b/4E41oNQPHtOoNCqFY+uQogP90qZ1w1
xlFX8ie/W3cuqhfzW6+/M3iCIwdjhBquvOo6mE3t2/lUcGXE20GayFsKnEmgpDJa
nxoG1+m+s5zCwDuukX8Lr1O7maTMwNVhm5P5QWeEPbGRN7yw+CfzcvPIbFYwnZ5x
XeC9Vtoj2Jbom8RV9uus8R5LfYBJ+HZh74wbGhIC2Kf9LrJTK7r92uVA
-----END CERTIFICATE-----"""

    plugin_root_ca_key = """-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----"""

    def __init__(self, configuration=""):
        self.cert_x509name = {
            'country_name': 'HU',
            'state_or_province_name': 'Budapest',
            'locality_name': 'Budapest',
            'organization_name': 'One Identity',
            'common_name': '',
        }
        self.cert_alt_domains = []
        self.cert_alt_ips = []

        if configuration is not "":
            try:
                configdict = literal_eval(configuration)
                self.plugin_root_ca = configdict['ca']
                self.plugin_root_ca_key = configdict['key']
            except Exception:
                pass

        self.root_ca_certificate = asymmetric.load_certificate(bytes(self.plugin_root_ca, 'utf-8'))
        self.root_ca_key = asymmetric.load_private_key(bytes(self.plugin_root_ca_key, 'utf-8'))

    def _sign_certificate(self):
        end_entity_public_key, end_entity_private_key = asymmetric.generate_pair(self.cert_keytype, bit_size=2048)
        end_entity_private_key = asymmetric.dump_private_key(end_entity_private_key, None)
        end_entity_subject = self.cert_x509name

        builder = CertificateBuilder(
            end_entity_subject,
            end_entity_public_key
        )

        builder.subject_alt_domains = self.cert_alt_domains
        builder.subject_alt_ips = self.cert_alt_ips
        builder.issuer = self.root_ca_certificate
        end_entity_certificate = builder.build(self.root_ca_key)
        end_entity_certificate = pem_armor_certificate(end_entity_certificate)
        return end_entity_certificate, end_entity_private_key

    _subject_type_mapping = {
        'C': 'country_name',
        'ST': 'state_or_province_name',
        'L': 'locality_name',
        'O': 'organization_name',
        'OU': 'organizational_unit_name',
        'CN': 'common_name',
        'emailAddress': 'email_address',
    }

    def _set_certificate_x509_name(self, x509name):
        for (t, v) in x509name:
            self.cert_x509name[self._subject_type_mapping[t]] = v

    def _set_certificate_keytype(self, keytype):
        # Certbuilder lists DSS key as DSA so we have to translate the string here
        if keytype == "dss": keytype = "dsa"
        if keytype not in ['dsa', 'rsa']:
            raise ValueError('Certificate type should be either \'rsa\' or \'dss\'')
        else:
            self.cert_keytype = keytype

    def _set_certificate_cn(self, cn):
        self.cert_x509name['common_name'] = cn

    def _set_certificate_addresses(self, addresses):
        for address in addresses:
            try:
                ip_address(address)
                self.cert_alt_ips.append(address)
            except ValueError:
                self.cert_alt_domains.append(address)

    def _build_response(self, cert, key):
        return {'key': key.decode('ascii'), 'chain': [cert.decode('ascii'), self.plugin_root_ca]}

    def generate_for_addresses(self, addresses: list, keytype: str):
        self._set_certificate_keytype(keytype)
        self._set_certificate_addresses(addresses)
        self._set_certificate_cn(addresses[0])
        return self._build_response(
            *self._sign_certificate()
        )

    def generate_for_username(self, username: str, keytype: str):
        self._set_certificate_keytype(keytype)
        self._set_certificate_cn(username)
        return self._build_response(
            *self._sign_certificate()
        )

    def generate_for_subject(self, x509name: list, keytype: str):
        self._set_certificate_keytype(keytype)
        self._set_certificate_x509_name(x509name)
        return self._build_response(
            *self._sign_certificate()
        )

Use the following snippet as the MANIFEST file:

# Name of the plugin, may contain [a-zA-Z0-9]
name: HelloSigningCaPlugin

# Version of the plugin, only for display purposes
version: 0.1

# Type of the plugin - this is a signingca plugin
type: signingca

# API version of the SCB the plugin was written for, in major.minor format
api: 1.0

# Free form description.
description: This is an example plugin used for testing.

# Entry point for the plugin (also for running with python3)
entry_point: main.py

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