The Photon operating system must enforce approved authorizations for logical access to information and system resources in accordance with applicable access control policies.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-239195	PHTN-67-000124	SV-239195r675393_rule		Medium

Description
If the system does not require authentication before it boots into single-user mode, anyone with vCenter console rights to the VCSA can trivially access all files on the system. GRUB2 is the boot loader for Photon OS and can be configured to require a password to boot into single-user mode or make modifications to the boot menu. Note: The VCSA does not support building grub changes via grub2-mkconfig.

Description

If the system does not require authentication before it boots into single-user mode, anyone with vCenter console rights to the VCSA can trivially access all files on the system. GRUB2 is the boot loader for Photon OS and can be configured to require a password to boot into single-user mode or make modifications to the boot menu. Note: The VCSA does not support building grub changes via grub2-mkconfig.

STIG	Date
VMware vSphere 6.7 Photon OS Security Technical Implementation Guide	2021-04-15

Details

Check Text ( C-42406r675391_chk )
At the command line, execute the following command: # grep -i ^password_pbkdf2 /boot/grub2/grub.cfg If there is no output, this is a finding. If the output does not begin with "password_pbkdf2 root", this is a finding.

Fix Text (F-42365r675392_fix)
At the command line, execute the following command: # grub2-mkpasswd-pbkdf2 Enter a secure password and ensure this password is stored for break-glass situations. The vCenter root account cannot be recovered without knowing this separate password. Copy the resulting encrypted string. An example string follows: grub.pbkdf2.sha512.10000.983A13DF3C51BB2B5130F0B86DDBF0DEA1AAF766BD1F16B7840F79CE3E35494C4B99F505C99C150071E563DF1D7FE1F45456D5960C4C79DAB6C49298B02A5558.5B2C49E12D43CC5A876F6738462DE4EFC24939D4BE486CDB72CFBCD87FDE93FBAFCB817E01B90F23E53C2502C3230502BC3113BE4F80B0AFC0EE956E735F7F86 Open /boot/grub2/grub.cfg with a text editor. Find the line that begins with "set rootpartition". Below this line, paste the following on its own line: set superusers="root" Below this, paste the following, substituting your own encrypted string from the steps above: password_pbkdf2 root The VCSA ships with one "menuentry" block by default. Copy that entire block and paste it right below that block. Example: menuentry "Photon" { linux "/"$photon_linux root=$rootpartition net.ifnames=0 $photon_cmdline coredump_filter=0x37 consoleblank=0 if [ "$photon_initrd" ]; then initrd "/"$photon_initrd fi } menuentry "Photon" { linux "/"$photon_linux root=$rootpartition net.ifnames=0 $photon_cmdline coredump_filter=0x37 consoleblank=0 if [ "$photon_initrd" ]; then initrd "/"$photon_initrd fi } Modify the first menuentry block to add the "--unrestricted" option as follows: menuentry "Photon" --unrestricted { Modify the second menuentry block to add the allowed user as follows: menuentry "Recover Photon" --users root { This concludes the fix. To verify, following is an example grub.cfg snippet: ... set rootpartition=PARTUUID=326e5b0f-42fb-471a-8209-18964c4a2ed3 set superusers="root" password_pbkdf2 root grub.pbkdf2.sha512.10000.983A13DF3C51BB2B5130F0B86DDBF0DEA1AAF766BD1F16B7840F79CE3E35494C4B99F505C99C150071E563DF1D7FE1F45456D5960C4C79DAB6C49298B02A5558.5B2C49E12D43CC5A876F6738462DE4EFC24939D4BE486CDB72CFBCD87FDE93FBAFCB817E01B90F23E53C2502C3230502BC3113BE4F80B0AFC0EE956E735F7F86 menuentry "Photon" --unrestricted { linux "/"$photon_linux root=$rootpartition net.ifnames=0 $photon_cmdline coredump_filter=0x37 consoleblank=0 if [ "$photon_initrd" ]; then initrd "/"$photon_initrd fi } menuentry "Recover Photon" --users root { linux "/"$photon_linux root=$rootpartition net.ifnames=0 $photon_cmdline coredump_filter=0x37 consoleblank=0 if [ "$photon_initrd" ]; then initrd "/"$photon_initrd fi }

Fix Text (F-42365r675392_fix)

At the command line, execute the following command:

# grub2-mkpasswd-pbkdf2

Enter a secure password and ensure this password is stored for break-glass situations. The vCenter root account cannot be recovered without knowing this separate password.

Copy the resulting encrypted string. An example string follows:

grub.pbkdf2.sha512.10000.983A13DF3C51BB2B5130F0B86DDBF0DEA1AAF766BD1F16B7840F79CE3E35494C4B99F505C99C150071E563DF1D7FE1F45456D5960C4C79DAB6C49298B02A5558.5B2C49E12D43CC5A876F6738462DE4EFC24939D4BE486CDB72CFBCD87FDE93FBAFCB817E01B90F23E53C2502C3230502BC3113BE4F80B0AFC0EE956E735F7F86

Open /boot/grub2/grub.cfg with a text editor. Find the line that begins with "set rootpartition". Below this line, paste the following on its own line:

set superusers="root"

Below this, paste the following, substituting your own encrypted string from the steps above:

password_pbkdf2 root

The VCSA ships with one "menuentry" block by default. Copy that entire block and paste it right below that block.

Example:
menuentry "Photon" {
linux "/"$photon_linux root=$rootpartition net.ifnames=0 $photon_cmdline coredump_filter=0x37 consoleblank=0
if [ "$photon_initrd" ]; then
initrd "/"$photon_initrd
fi
}
menuentry "Photon" {
linux "/"$photon_linux root=$rootpartition net.ifnames=0 $photon_cmdline coredump_filter=0x37 consoleblank=0
if [ "$photon_initrd" ]; then
initrd "/"$photon_initrd
fi
}

Modify the first menuentry block to add the "--unrestricted" option as follows:

menuentry "Photon" --unrestricted {

Modify the second menuentry block to add the allowed user as follows:

menuentry "Recover Photon" --users root {

This concludes the fix. To verify, following is an example grub.cfg snippet:

...
set rootpartition=PARTUUID=326e5b0f-42fb-471a-8209-18964c4a2ed3
set superusers="root"
password_pbkdf2 root grub.pbkdf2.sha512.10000.983A13DF3C51BB2B5130F0B86DDBF0DEA1AAF766BD1F16B7840F79CE3E35494C4B99F505C99C150071E563DF1D7FE1F45456D5960C4C79DAB6C49298B02A5558.5B2C49E12D43CC5A876F6738462DE4EFC24939D4BE486CDB72CFBCD87FDE93FBAFCB817E01B90F23E53C2502C3230502BC3113BE4F80B0AFC0EE956E735F7F86

menuentry "Photon" --unrestricted {
linux "/"$photon_linux root=$rootpartition net.ifnames=0 $photon_cmdline coredump_filter=0x37 consoleblank=0
if [ "$photon_initrd" ]; then
initrd "/"$photon_initrd
fi
}

menuentry "Recover Photon" --users root {
linux "/"$photon_linux root=$rootpartition net.ifnames=0 $photon_cmdline coredump_filter=0x37 consoleblank=0
if [ "$photon_initrd" ]; then
initrd "/"$photon_initrd
fi
}