Reference Guide

Table 22. System Security details (continued)
Option Description
AC Power Recovery Delay Sets the time delay for the system to power up after AC power is restored to
the system. This option is set to Immediate by default. When this option is set to
Immediate, there is no delay for power up. When this option is set to Random, the
system creates a random delay for power up. When this option is set to User Defined,
the system delay time is manually to power up.
User Defined Delay (60 s to 600
s)
Sets the User Defined Delay option when the User Defined option for AC Power
Recovery Delay is selected.
UEFI Variable Access Provides varying degrees of securing UEFI variables. When set to Standard (the
default), UEFI variables are accessible in the operating system per the UEFI
specification. When set to Controlled, selected UEFI variables are protected in the
environment and new UEFI boot entries are forced to be at the end of the current boot
order.
In-Band Manageability Interface When set to Disabled , this setting hides the Management Engine's (ME), HECI devices,
and the system's IPMI devices from the operating system. This prevents the operating
system from changing the ME power capping settings, and blocks access to all in-
band management tools. All management should be managed through out-of-band. This
option is set to Enabled by default.
NOTE: BIOS update requires HECI devices to be operational and DUP updates
require IPMI interface to be operational. This setting needs to be set to Enabled to
avoid updating errors.
Smm Security Migration Enables or disables the UEFI SMM security migration protections.
Secure Boot Enables Secure Boot, where the BIOS authenticates each pre-boot image by using the
certificates in the Secure Boot Policy. Secure Boot is set to Disabled by default.
Secure Boot Policy When Secure Boot policy is set to Standard, the BIOS uses the system manufacturer’s
key and certificates to authenticate pre-boot images. When Secure Boot policy is set to
Custom, the BIOS uses the user-defined key and certificates. Secure Boot policy is set
to Standard by default.
Secure Boot Mode Configures how the BIOS uses the Secure Boot Policy Objects (PK, KEK, db, dbx).
If the current mode is set to Deployed Mode, the available options are User Mode and
Deployed Mode. If the current mode is set to User Mode, the available options are
User Mode, Audit Mode, and Deployed Mode.
Table 23. Secure Boot Mode
Options Descriptions
User Mode
In User Mode, PK must be installed, and BIOS performs signature
verification on programmatic attempts to update policy objects.
The BIOS allows unauthenticated programmatic transitions between
modes.
Audit mode
In Audit Mode, PK is not present. BIOS does not authenticate
programmatic update to the policy objects and transitions between
modes. The BIOS performs a signature verification on pre-boot images
and logs the results in the image Execution Information Table, but
executes the images whether they pass or fail verification.
Audit Mode is useful for programmatic determination of a working set
of policy objects.
Deployed
Mode
Deployed Mode is the most secure mode. In Deployed Mode, PK
must be installed and the BIOS performs signature verification on
programmatic attempts to update policy objects.
Deployed Mode restricts the programmatic mode transitions.
20 Pre-operating system management applications