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Crescendo is a powerful framework for wrapping command-line tools and converting their output into structured PowerShell objects. In this article, we’ll explore how to use Crescendo to wrap certutil.exe, a versatile Windows utility for certificate management, and transform its output into usable PowerShell objects.
You Should Know:
1. Install Crescendo Module
Before using Crescendo, ensure you have the module installed:
Install-Module -Name Microsoft.PowerShell.Crescendo -Force -AllowPrerelease
2. Create a Crescendo Configuration for certutil
Define a JSON configuration to wrap `certutil.exe` commands. Below is an example for fetching certificate store details:
{
"$schema": "https://aka.ms/Crescendo/Schema",
"Commands": [
{
"Verb": "Get",
"Noun": "CertificateStore",
"OriginalName": "certutil",
"OriginalCommandElements": ["-store", "My"],
"OutputHandlers": [
{
"ParameterSetName": "Default",
"HandlerType": "Inline",
"Handler": "$PSItem | ConvertFrom-String -PropertyNames Thumbprint,Subject,Issuer,FriendlyName"
}
]
}
]
}
3. Generate the PowerShell Cmdlet
Compile the configuration into a PowerShell module:
Export-CrescendoModule -ConfigurationFile .\certutil-crescendo.json -ModuleName CertUtilWrapper
4. Import and Use the New Cmdlet
Import-Module .\CertUtilWrapper.psd1 Get-CertificateStore | Format-Table
5. Example: Exporting Certificates
Extend Crescendo to export certificates:
{
"Verb": "Export",
"Noun": "Certificate",
"OriginalName": "certutil",
"OriginalCommandElements": ["-exportPFX", "-p", "Password123", "-f"],
"Parameters": [
{
"Name": "Thumbprint",
"OriginalName": "",
"ParameterType": "string",
"Mandatory": true
}
]
}
6. Parsing Complex Output
For advanced parsing, use regex or custom script blocks:
$output = certutil -view
$parsed = $output -split "<code>r</code>n" | Where-Object { $_ -match "Serial Number:" }
7. Automating Certificate Audits
Combine Crescendo with scheduled tasks for automated certificate checks:
$certificates = Get-CertificateStore
$expiringSoon = $certificates | Where-Object { $_.NotAfter -lt (Get-Date).AddDays(30) }
$expiringSoon | Export-Csv -Path "ExpiringCerts.csv"
8. Linux Alternative (OpenSSL)
For Linux-based systems, use OpenSSL for similar tasks:
openssl x509 -in cert.pem -noout -text | grep "Subject:"
9. Windows Certificate Store via PowerShell
Without Crescendo, use native PowerShell cmdlets:
Get-ChildItem Cert:\LocalMachine\My
10. Security Considerations
- Always secure exported PFX files with strong passwords.
- Audit certificate permissions regularly:
Get-Acl -Path Cert:\LocalMachine\My | Format-List
What Undercode Say:
Crescendo bridges the gap between legacy CLI tools and modern PowerShell automation. By wrapping certutil.exe, we make certificate management more intuitive and scriptable. For enterprise environments, this approach ensures consistency and reduces manual errors.
Prediction
As PowerShell continues evolving, expect more tools like Crescendo to emerge, simplifying the transition from CLI-based utilities to object-oriented automation.
Expected Output:
Thumbprint Subject Issuer FriendlyName - - A1B2C3D4... CN=example.com CN=CA-Root Web Server Cert
URL: Using Crescendo to Tame certutil.exe
References:
Reported By: Jakehildreth Using – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
