Script to replace VMware Unified Access Gateway certificates (ADMIN and Internet)

Our certificates are coming close to expiry, and we use VMware Unified Access Gateway for Internal and External traffic tunneling. This brings us to perform the replacement of the expiring certificates on 12 UAG Appliances. Performing this activity from the GUI is straight forward. However, we need to perform this activity on 12 appliances.

Thanks to Mark Benson for the motivation, and I went ahead and created a script to perform this activity at further ease, sit back, relax and have a coffee!

Pre-requisites:

• You need the CAchain pem and RSA private key certificate output in one line. Please make sure you run the following command to grab the output in a single line
  • Linux/Unix command – awk ‘NF {sub(/\r/, “”); printf “%s\n”,$0;}’ cert-name.pem
  • Linux/Unix command – awk ‘NF {sub(/\r/, “”); printf “%s\n”,$0;}’ cert-namersapriv.pem
  • I saved the certificate files on a Linux machine and then ran the above command. Pasted the output in Notepad++, which is in one line.
  • Doco reference
  • The CAChain pem certificate should include (MainCA content, Subordinate Certificate content and Root Certificate content without any spaces between them.)
• There are seperate API calls for the certificate replacement for the ADMIN and Internet facing. You can comment or un-comment the block as per your requirement
  • /rest/v1/config/certs/ssl/ADMIN
  • /rest/v1/config/certs/ssl/END_USER
• The IP address or Hostname of the UAG Appliance along with the admin password.

##############################################################################################################################################
# Replace the ADMIN and Internet Facing certificate on the UAG Appliance
# Uncomment if you dont plan to do both the interfaces (Internet/ADMIN)
# Get the certificate in one line following this documentation 
# https://docs.vmware.com/en/Unified-Access-Gateway/3.10/com.vmware.uag-310-deploy-config.doc/GUID-870AF51F-AB37-4D6C-B9F5-4BFEB18F11E9.html
# Author - Aresh Sarkari (Twitter - @askaresh)
##############################################################################################################################################

#UAGServer Name or IP
$UAGServer = "10.1.1.1"

#Ignore cert errors
add-type @"
    using System.Net;
    using System.Security.Cryptography.X509Certificates;
    public class TrustAllCertsPolicy : ICertificatePolicy {
        public bool CheckValidationResult(
            ServicePoint srvPoint, X509Certificate certificate,
            WebRequest request, int certificateProblem) {
            return true;
        }
    }
"@
[System.Net.ServicePointManager]::CertificatePolicy = New-Object TrustAllCertsPolicy
[System.Net.ServicePointManager]::SecurityProtocol = [System.Net.SecurityProtocolType]'Ssl3,Tls,Tls11,Tls12'


#API Call to make the intial connection to the UAG Appliance##
$Uri = "https://$UAGServer`:9443/rest/v1/config/adminusers/logAdminUserAction/LOGIN"

$Username = "admin"
$Password = "enteryouradminpassword"

$Headers = @{ Authorization = "Basic {0}" -f [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(("{0}:{1}" -f $Username,$Password))) }

Invoke-WebRequest -SessionVariable DaLogin -Uri $Uri -Headers $Headers

#The PEM Certificate + Private Key in RSA Format
#The certificate has to be in online using linux command - awk 'NF {sub(/\r/, ""); printf "%s\\n",$0;}' cert-name.pem 
$certificatersaContent = "-----BEGIN RSA PRIVATE KEY-----\nMIIEo... followed by a large block of text...\n-----END RSA PRIVATE KEY-----\n"
$certificateContent = "-----BEGIN CERTIFICATE-----\nMIIEo... followed by a large block of text...\n-----END CERTIFICATE-----\n"

#Body to replace the certificate
$body = @{
  privateKeyPem = $certificatersaContent
  certChainPem = $certificateContent
} 

#Converting the Json and line breaks in strings 
#https://communary.net/2018/03/30/quick-tip-convertto-json-and-line-breaks-in-strings/
$Jsonbody = ($body | ConvertTo-Json).Replace('\\n','\n')

#API to replace the Admin Certificate of the UAG Appliance
#Please note that the Backtick ` is required in order to escape the colon
$outputadmin = Invoke-WebRequest -WebSession $DaLogin -Method Put -Uri "https://$UAGServer`:9443/rest/v1/config/certs/ssl/ADMIN" -Body $Jsonbody -ContentType "application/json" -Verbose

#API to replace the Internet facing Certificate of the UAG Appliance
#Please note that the Backtick ` is required in order to escape the colon
$outputenduser = Invoke-WebRequest -WebSession $DaLogin -Method Put -Uri "https://$UAGServer`:9443/rest/v1/config/certs/ssl/END_USER" -Body $Jsonbody -ContentType "application/json" -Verbose

GitHub – scripts/vmwareuagcertreplace at master · askaresh/scripts (github.com)

Observations:

• The array within the $body has further line breaks, which needs to adjust. I had to spend a considerable amount of time. Thanks to this blog post which came in hand. Powershell function ConvertTo-Json
• The Powershell function Invoke-Webrequest and the -URI I had to add the Backtick ` in order to escape the colon
• The key of the above script is the CAChain certificate and RSA Private Key certificate to be available online.

I hope you will find this script useful to replace or change the certificate on the VMware Unified Access Gateway appliances. A small request if you further enhance the script or make it more creative, I hope you can share it back with me?

Thanks,
Aresh Sarkari

Tags: Horizon, PowerShell, Unified Access Gateway, VMware, VMware Horizon