Title

Apple iOS must have cloud keychain syncing features disabled. (Cat II impact)

Discussion

The iCloud Keychain is an iOS function that will store users' account names and passwords in iCloud, then sync this data between the users' Macs, iPhones, and iPads. An adversary may use any of the stored iCloud keychain passwords after unlocking one of the synchronized devices. If a user is synchronizing devices, the user must protect all of the devices to prevent unauthorized use of the passcodes. Moreover, the keychain being transmitted through the cloud opens the possibility that a well-resourced, sophisticated adversary could compromise the cloud-transmitted keychain. Not allowing the iCloud Keychain feature mitigates the risk of the encrypted set of passwords being compromised by being transmitted through the cloud or synchronized across multiple devices.

Check Content

This check procedure is performed on both the iOS Over-the-Air management tool and the iOS 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 Over-the-Air management tool, verify "Allow iCloud keychain" is unchecked. For example, in Apple Configurator: 1. Ask the MDM administrator to open the relevant configuration profile. 2. Display the "Restrictions" payload. 3. Verify "Allow iCloud keychain" is unchecked. Alternatively, verify the text "<key>allowCloudKeychainSync</key><false/>" appears in the configuration profile (.mobileconfig file). On the iOS device: 1. Open the Settings app. 2. Tap "iCloud". 3. Verify "iCloud Keychain" is not listed. If "Allow iCloud keychain" is checked in the iOS Over-the-Air management tool, "<key>allowCloudKeychainSync</key><true/>" appears in the configuration profile, or if "iCloud Keychain" is listed on the iOS device under iCloud, this is a finding.

Fix Text

Configure Apple iOS not to allow iCloud keychain. In the iOS Over-the-Air management tool, uncheck "Allow iCloud keychain". For example, in Apple Configurator, edit the Configuration Profile and uncheck "Allow iCloud keychain".

Additional Identifiers

Rule ID:

Vulnerability ID: V-43217

Group Title:

Expert Comments

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