The amount of private memory an application pool uses for each IIS 8.5 website must be explicitly set.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-76871	IISW-SI-000254	SV-91567r2_rule		Medium

Description
IIS application pools can be periodically recycled to avoid unstable states possibly leading to application crashes, hangs, or memory leaks. By default, application pool recycling is overlapped, which means the worker process to be shut down is kept running until after a new worker process is started. After a new worker process starts, new requests are passed to it. The old worker process shuts down after it finishes processing its existing requests, or after a configured time-out, whichever comes first. This way of recycling ensures uninterrupted service to clients.

Description

IIS application pools can be periodically recycled to avoid unstable states possibly leading to application crashes, hangs, or memory leaks. By default, application pool recycling is overlapped, which means the worker process to be shut down is kept running until after a new worker process is started. After a new worker process starts, new requests are passed to it. The old worker process shuts down after it finishes processing its existing requests, or after a configured time-out, whichever comes first. This way of recycling ensures uninterrupted service to clients.

STIG	Date
IIS 8.5 Site Security Technical Implementation Guide	2019-10-01

Details

Check Text ( C-76527r2_chk )
Note: Recycling Application Pools can create an unstable environment in a 64-bit SharePoint environment. If operational issues arise, with supporting documentation from the ISSO this check can be downgraded to a Cat III. Note: If the IIS Application Pool is hosting Microsoft SharePoint, this is Not Applicable. Open the IIS 8.5 Manager. Perform for each Application Pool. Click the “Application Pools”. Highlight an Application Pool and click "Advanced Settings" in the “Action” Pane. Scroll down to the "Recycling" section and verify the value for "Private Memory Limit" is set to a value other than "0". If the "Private Memory Limit" is set to a value of "0", this is a finding.

Check Text ( C-76527r2_chk )

Note: Recycling Application Pools can create an unstable environment in a 64-bit SharePoint environment. If operational issues arise, with supporting documentation from the ISSO this check can be downgraded to a Cat III.

Note: If the IIS Application Pool is hosting Microsoft SharePoint, this is Not Applicable.

Open the IIS 8.5 Manager.

Perform for each Application Pool.

Click the “Application Pools”.

Highlight an Application Pool and click "Advanced Settings" in the “Action” Pane.

Scroll down to the "Recycling" section and verify the value for "Private Memory Limit" is set to a value other than "0".

If the "Private Memory Limit" is set to a value of "0", this is a finding.

Fix Text (F-83567r1_fix)
Open the IIS 8.5 Manager. Click the “Application Pools”. Perform for each Application Pool. Highlight an Application Pool and click "Advanced Settings" in the “Action” Pane. Scroll down to the "Recycling" section and set the value for "Private Memory Limit" to a value other than "0".