By default, NetWitness Endpoint 11.x creates a self-signed Certificate Authority during its initial installation, and uses this CA to generate certificates for the endpoint agent and the local reverse proxy that handles all incoming agent communications. Because all these certificates are generated from the same CA chain, they automatically trust each other and enable seamless, easy, and secure communications between agents and the endpoint server.
But what if this self-signed CA cannot be used within your organization? For a number of very valid reasons, many orgs might not allow software using a self-signed certificate, and may instead be required to use their own trusted CAs. If this is the case, we have a couple options - an easy way, and a hard way.
This blog covers the easy way.
The only real requirement for the easy way is that we are able to create an Intermediate CA certificate and its private key from our CA chain (or use an existing pair), and that this Intermediate CA is allowed to generate an additional, subordinate CA under it.
For my testing, "Root-ca" was my imaginary company's Root CA, and I created "My Company Intermediate CA" for use in my 11.4 Endpoint Log Hybrid.
(I'm no expert in certificates, but I can say that all the Intermediate CAs I created that had explicit extendedKeyUsage extensions failed. The only Intermediate CAs I could get to work included "All" of the Intended Purposes. If you know more about CAs and the specific extendedKeyUsage extensions needed for a CA to be able to create subordinate CAs, I'd be interested to know what they are.)
Once we have an Intermediate CA certificate and its private key, we need to make sure they are in PEM format. There are a number of ways to convert and check keys and certificates, and a whole bunch of resources online to help with this this, so I won't cover any of the various conversion commands or methods here.
If the CA certificate looks like this, then it is most likely in the correct format:
And if the private key looks like this, then it is most likely in the correct format:
-----BEGIN PRIVATE KEY-----
-----END PRIVATE KEY-----
Our last step in this process has to occur at a very specific point during the endpoint log hybrid's installation - after we have run the nwsetup-tui command and the host has been enabled within the NetWitness UI, but before we install the Endpoint Log Hybrid services:
- on the endpoint host, create directory /etc/pki/nw/nwe-ca
- place the CA certificate and CA private key files in this directory and name them nwerootca-cert.pem and nwerootca-key.pem, respectively
The basis for this process comes directly from the "Configure Multiple Endpoint Log Hybrid Hosts" step in the Post Installation tasks guide (https://community.rsa.com/docs/DOC-101660#NetWitne), if we want a bit more context or details on when this step should occur and how to do it properly.
Once we've done this, we can now install the Endpoint Log Hybrid services on the host.
I suggest you watch the installation log file on the endpoint server, because if the Intermediate CA does not have all the necessary capabilities, the installation will fail and this log file can help us identify which step (if my own experience is any guide, then it will most likely fail during the attempt to create the subordinate Endpoint Intermediate CA --> /etc/pki/nw/nwe-ca/esca-cert.pem😞
# tail -f /var/log/netwitness/config-management/chef-solo.log
If all goes well, we'll be able to check that our endpoint-server is using our Intermediate CA by browsing to https://<endpoint_server_IP_or_FQDN> and checking the certificate presented by the server:
And our client.p12 certificate bundle within the agentPackager will be generated from the same chain:
And that's it!
Any agent packages we generate from this point forward will use the client.p12 certificates generated from our CA. Likewise, all agent-server communications will be encrypted with the certificates generated from our CA.
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