Apple iOS/iPadOS must implement the management setting: enable USB Restricted Mode.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-97497	AIOS-13-012500	SV-106601r1_rule		Medium

Description
The USB lightning port on an iOS device can be used to access data on the device. The required settings ensure the Apple device password is entered before a previously trusted USB accessory can connect to the device. SFR ID: FMT_SMF_EXT.1.1 #47

STIG	Date
Apple iOS/iPadOS 13 Security Technical Implementation Guide	2019-09-23

Details

Check Text ( C-96333r1_chk )
This is a Supervised-only control. If the iPhone or iPad being reviewed is not Supervised by the MDM, this control is automatically a finding. If the iPhone or iPad being reviewed is Supervised by the MDM, review configuration settings to confirm "Allow USB Restricted Mode" is enabled. This check procedure is performed on both the device management tool and the iPhone and iPad device. Note: If an organization has multiple configuration profiles, then the check procedure must be performed on the relevant configuration profiles applicable to the scope of the review. In the iOS management tool, verify "Allow USB Restricted Mode" is checked. On the iPhone/iPad device: 1. Open the Settings app. 2. Tap "General". 3. Tap "Profiles" or "Profiles & Device Management" or "Device Management". 4. Tap the Configuration Profile from the iOS management tool containing the restrictions policy. 5. Tap "Restrictions". 6. Verify "Allow USB Restricted Mode" is listed. If "Allow USB Restricted Mode" is not enabled in both the management tool and on the Apple device, this is a finding. Note: "Allow USB Restricted Mode" may be called “Allow USB accessories while device is locked” in some MDM consoles. The required logic is to disable USB accessory connections when the device is locked.

Check Text ( C-96333r1_chk )

This is a Supervised-only control. If the iPhone or iPad being reviewed is not Supervised by the MDM, this control is automatically a finding.

If the iPhone or iPad being reviewed is Supervised by the MDM, review configuration settings to confirm "Allow USB Restricted Mode" is enabled.

This check procedure is performed on both the device management tool and the iPhone and iPad device.

Note: If an organization has multiple configuration profiles, then the check procedure must be performed on the relevant configuration profiles applicable to the scope of the review.

In the iOS management tool, verify "Allow USB Restricted Mode" is checked.

On the iPhone/iPad device:
1. Open the Settings app.
2. Tap "General".
3. Tap "Profiles" or "Profiles & Device Management" or "Device Management".
4. Tap the Configuration Profile from the iOS management tool containing the restrictions policy.
5. Tap "Restrictions".
6. Verify "Allow USB Restricted Mode" is listed.

If "Allow USB Restricted Mode" is not enabled in both the management tool and on the Apple device, this is a finding.

Note: "Allow USB Restricted Mode" may be called “Allow USB accessories while device is locked” in some MDM consoles. The required logic is to disable USB accessory connections when the device is locked.

Fix Text (F-103177r1_fix)
Install a configuration profile to disable the allow USB Restricted Mode in the management tool. This a Supervised-only control. Note: This control is called “Allow USB accessories while device is locked” in Apple Configurator and the control logic is opposite to what is listed here. Make sure the MDM policy rule is set correctly (to disable USB accessory connections when the device is locked).

Fix Text (F-103177r1_fix)

Install a configuration profile to disable the allow USB Restricted Mode in the management tool. This a Supervised-only control.

Note: This control is called “Allow USB accessories while device is locked” in Apple Configurator and the control logic is opposite to what is listed here. Make sure the MDM policy rule is set correctly (to disable USB accessory connections when the device is locked).