The IIS 10.0 website must have a unique application pool.

Severity
Group ID
Group Title
Version
Rule ID
Date
STIG Version
mediumV-218771SRG-APP-000516-WSR-000174IIST-SI-000251SV-218771r961863_rule2025-02-112
Description
Application pools isolate sites and applications to address reliability, availability, and security issues. Sites and applications may be grouped according to configurations, although each site will be associated with a unique application pool.
ℹ️ Check
Note: If the IIS Application Pool is hosting Microsoft SharePoint, this is Not Applicable. If this IIS 10.0 installation is supporting Microsoft Exchange, and not otherwise hosting any content, this requirement is Not Applicable. Open the IIS 10.0 Manager. Click "Application Pools". In the list of Application Pools, review the "Applications" column and verify unique application pools for each website. If any Application Pools are being used for more than one website, this is a finding.
✔️ Fix
Open the IIS 10.0 Manager. Click the site name under review. Assign a unique application pool to each website.