Sign and verify an ACC plugin

Create a self-signed certificate for an Agent Client Collector (ACC) plugin and verify the signature to enable validation of the signed plugin on endpoint devices.

Before you begin

• Create the ACC plugin tar.gz file on your local computer.
• Make sure that OpenSSL is installed on your local computer.

Role required: admin

Procedure

1. Generate a 2048-bit RSA key and a corresponding self-signed certificate with one year validity by using the following command:

   openssl req -nodes -x509 -sha256 -newkey rsa:2048 -keyout "sign.key" -out "sign.crt" -days 365 -subj "/C=IN/ST=TG/L=HYD/O=servicenow/OU=acme/CN=sign"

   This command creates a private key (sign.key) and a public certificate (sign.crt).
2. Sign the plugin file with your private key.

   openssl dgst -sha256 -sign "sign.key" -out sign.txt.sha256 plugin name.tar.gz

3. Extract the public key from the certificate for signature verification.

   openssl x509 -in "sign.crt" -pubkey -noout > pubkey.pem

4. Verify the signature using the public key to confirm the file was signed correctly.

   openssl dgst -sha256 -verify pubkey.pem -signature sign.txt.sha256 plugin name.tar.g

5. Encode the signature file using Base64 to enable the ACC agent to validate the plugin.
   • macOS

     base64 -i sign.txt.sha256 -o sign.txt.sha256_encode64.sig

   • Windows

     openssl enc -base64 -in sign.txt.sha256 -out sign.txt.sha256_encode64.sig

6. Create a directory to store the signed plugin.

   mkdir signed-plugin

7. Move the plugin archive and signature file to the new directory.

   mv plugin name.tar.gz signed-plugin/
   
   mv sign.txt.sha256_encode64.sig signed-plugin/

8. Navigate to the new directory.

   cd signed-plugin

9. Create a tar.gz file containing both the plugin archive and the signature file.

   tar -C . -zcvf ../sign-test.tar.gz *

10. Copy and place the self-signed certificate (sign.crt) in the certificate directory ([agent_root]/cert) of the ACC agent using one of the following options:
    • Copy the file manually.
    • Distribute the certificate to agent devices using a device management utility such as Jamf or Microsoft Intune.
11. Add the certificate to the agent trust store.
    For more information, see Add a self-signed certificate to your operating system's truststore.
12. Upload the signed ACC plugin to the ServiceNow instance.
    For more information, see Create and edit Agent Client Collector plugins.