Clean up expired certificates from AD

Security MVP Vadims Podans just did a great post on using PowerShell to remove expired user certificates from Active Directory.

In a nutshell,

• If your company is using certificates for user authentication or encryption, these expire every now and then,
• Your Enterprise CA in that case appends new certificates to users’ userCertificate attribute, while leaving expired certs there as well,
• Over time these increasingly clutter your AD, making administration more difficult and negatively affecting AD replication traffic.

Luckily, cleaning up expired certificates with PowerShell is extremely easy.

To do the clean-up for a specific user you can run this one-liner:

Get-QADUser username | Remove-QADCertificate -Valid:$false

To clean-up the entire domain, just do:

Get-QADUser | Remove-QADCertificate -Valid:$false

See Vadim’s original post for details.

Read more about PKI management with PowerShell here.

PKI management with PowerShell

Complete guide for security certificate management with AD cmdlets 1.4 got recently published here and is a must-read if you want to automate your public key infrastructure (PKI).

PKI allows security administrators to uniquely identify and trust hardware devices by using digital certificates. This technique is one of the most secure access strategies, but can also be complicated to set up and manage. This guide reviews the security concepts surrounding digital certificate management and details how the AD-PKI cmdlets can be used with Active Directory to simplify PKI management.

Here’s the table of content from the guide:

• Understanding Digital Certificates
  • Cryptography Fundamentals
    • Symmetric Encryption
    • Asymmetric Encryption
    • Best Practices for Symmetric and Asymmetric Encryption
• Types of Certificates
  • X509 Certificate Version 1
  • X509 Certificate Version 2
  • X509 Certificate Version 3
    • Common Certificate Extensions
• Certificate Revocation List
  • X509 Certificate Revocation List Version 1
  • X509 Certificate Revocation List Version 2
    • Common CRL Extensions
• Certificate Stores and Containers
  • Local Certificate Stores
  • Active Directory Certificate Containers
• Certificate cmdlet Descriptions
• Object Structures of Certificate Stores, Certificates, and CR
  • Certificate Store
  • Certificate
  • Certificate Revocation List (CRL)
• Using Quest AD PKI-related cmdlets
  • Working with Certificate Stores
    • Explore Certificate Store
    • Create Certificate Store Container
    • Delete Certificate Store Container
  • Adding Certificates to a Certificate Store
    • Certificate File Types
    • Import a Single Certificate
    • Import a Pkcs7 Certificate Container
    • Import a Serialized Store
    • Import a Pkcs12 Certificate with a Private Key
    • Add Imported Certificates to a Store
    • Add an Imported Certificate to a User Account
    • Advanced Techniques
  • Exporting Certificates from a Certificate Store
    • Simple Certificate Export
    • Export a Certificate with a Private Key
    • Export Multiple Certificates
• Working with Certificate Revocation Lists (CRLs)
  • Add CRLs to a Certificate Store
  • Export CRLs from a Certificate Store
  • Remove a CRL from a Certificate Store
• Manage Active Directory PKI-related Containers
  • Publish a Certificate to Active Directory Containers
  • Remove a Certificate from Active Directory Containers
  • Publish CRLs to Active Directory Containers
  • Remove CRLs from Active Directory

Download the ebook “Guide for Using QuestAD-PKI cmdlets: Using PowerShell to manage your security certificates” and get the most out of your PKI environment.