Information
On Apple iOS devices, users can access the device's contact database or calendar to obtain phone numbers and other information using a human voice even when the mobile device is locked. Often this information is Personally Identifiable Information (PII), which is considered sensitive. It could also be used by an adversary to profile the user or engage in social engineering to obtain further information from other unsuspecting users. Disabling access to the contact database and calendar in these situations mitigates the risk of this attack. The AO may waive this requirement with written notice if the operational environment requires this capability.
SFR ID: FMT_SMF_EXT.1.1 #8b
NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.
Solution
Install a configuration profile to disable Siri while the device is locked.