6.7

Table Of Contents
UEFI Secure Boot Overview
ESXi version 6.5 and later supports UEFI secure boot at each level of the boot stack.
Note Before you use UEFI Secure Boot on a host that was upgraded to ESXi 6.5, check for compatibility
by following the instructions in Run the Secure Boot Validation Script on an Upgraded ESXi Host. If you
upgrade an ESXi host by using esxcli commands, the upgrade does not update the bootloader. In that
case, you cannot perform a secure boot on that system.
Figure 31. UEFI Secure Boot
UEFI firmware
Management apps (hostd, dcui, etc.)
Drivers and modules
ESXi base system
VMkernel
bootloader
Secure boot VIB verifier
VMware
public key
UEFI secure boot
enabled machine
UEFI CA
public key
Root
of trust
1
1
2
VMware
public key
With secure boot enabled, the boot sequence proceeds as follows.
1 Starting with vSphere 6.5, the ESXi bootloader contains a VMware public key. The bootloader uses
this key to verify the signature of the kernel and a small subset of the system that includes a secure
boot VIB verifier.
2 The VIB verifier verifies every VIB package that is installed on the system.
At this point, the entire system boots with the root of trust in certificates that are part of the UEFI firmware.
UEFI Secure Boot Troubleshooting
If secure boot does not succeed at any level of the boot sequence, an error results.
vSphere Security
VMware, Inc. 103