Question

Difficulty: MediumPublic Key Infrastructure and Certificate Management

An IT administrator is deploying multiple internal web applications under subdomains of an enterprise domain (such as `hr.corp.example.com` and `finance.corp.example.com`). To simplify administrative overhead and ensure all current and future first-level subdomains are secured under a single TLS certificate issued by the internal Certificate Authority, which of the following certificate features should be specified during the Certificate Signing Request (CSR) process?

  1. A wildcard domain entry configured within the Subject Alternative Name (SAN) extensionAnswer
  2. B
    Generating the private key on the Certificate Authority server and exporting it inside the CSR payload
  3. C
    Embedding symmetric session encryption keys into the extended key usage field of the request
  4. D
    Configuring the digital signature usage attribute to perform bulk data encryption for connected clients

Answer

A wildcard domain entry configured within the Subject Alternative Name (SAN) extension should be requested during CSR creation.
Specifying a wildcard domain (e.g., `*.corp.example.com`) in the Subject Alternative Name (SAN) extension allows a single certificate to authenticate all first-level subdomains under the specified domain. Modern clients require domain names and wildcard aliases to be declared in the SAN extension to pass validation checks.

Step-by-Step Solution

1
Identify the administrative requirement
The requirement is to secure multiple subdomains (`hr.corp.example.com`, `finance.corp.example.com`) under a single certificate without issuing separate certificates for each hostname.
Issuing a single certificate reduces administrative complexity and certificate maintenance overhead.
2
Evaluate PKI certificate attributes and extensions
A wildcard notation (`*.corp.example.com`) in the Subject Alternative Name (SAN) field permits any host matching that single subdomain level to present the certificate validly.
Modern TLS implementations and web browsers mandate the SAN extension for hostname matching.

Key Concept

Public Key Infrastructure - Wildcard Certificates and SAN Extensions
Estimated Time:1m 0s
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