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CaseyW's avatar
CaseyW
11 months ago
Solved

How to create datasources from powershell script

Hello, I wrote a PS script that takes a look at all issued certs on my microsoft CA and outputs 4 columns, The name of the cert, the effective date, the expiration date and the days remaining until ...
powershell
  • Stuart_Weenig's avatar
    Stuart_Weenig
    11 months ago

    Alright, assuming you’re not going to be running this code on your collector but on different systems, you’ll have to put your script into a scriptblock and run it as shown here.

    Assuming your common names in production will actually be unique, just use for loop to make your discovery scriptblock write-host output look like this:

    cert.domain.com##cert.domain.com
    cert.domain.com##cert.domain.com
    cert.domain.com##cert.domain.com
    cert.domain.com##cert.domain.com

    And use pretty much the same code (but different for loop) to make your collection scriptblock write-host this

    cert.domain.com.daysRemaining: 112
    cert.domain.com.daysRemaining: 121
    cert.domain.com.daysRemaining: 305
    cert.domain.com.daysRemaining: 310

    Then just setup a datapoint using ‘multiline key-value pairs’ and make the interpreter “##WILDVALUE##.daysRemaining”.

    Then just set whatever threshold you want on that datapoint.

    Have you checked that this has not already been built by someone else?

Jacob_Ortony's avatar
Jacob_Ortony
11 months ago

You can simplify this script if you use Get-ChildItem to grab the certs directly from the certificate store. Using the Powershell provider usually takes care of the variable typing and formatting which is very nice. Below, I pulled out EnhancedKeyUsageList, but the GetFormat() method might align to your preference for CertUtil template name schema. 

Example: 

$DesiredProperties = "CommonName,NotBefore,NotAfter,EnhancedKeyUsageList"

$AllCerts = Get-ChildItem -Recurse -Path "Cert:\" | Where-Object {$_.Thumbprint} | Select-Object -Property $DesiredProperties


## Other neat uses of Get-ChildItem for the Powershell Certificate provider
# $CodeSigningCert = Get-ChildItem -Recurse -Path "Cert:\CurrentUser\My" -CodeSigningCert
# $RemoteAuthCert = Get-ChildItem -Recurse -Path "Cert:\CurrentUser\My" -SSLServerAuthentication

Also, if you’re looking for performance optimizations: 

  • Using “+=” copies everything from the initial memory space into a new memory space with the extra object appended to the end. This is fine for small datasets, but you will see large performance impacts (and memory requirements) with increasing size.
  • Select-String is extremely efficient for parsing through text, even more so than falling back to .NET in many cases. Looping through line by line with foreach, or Foreach-Object will be slower especially when used with unoptimized regex or match statements (which is another ~deep subject =).