Ubuntu operating systems booted with a BIOS must require authentication upon booting into single-user and maintenance modes.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-75505	UBTU-16-010380	SV-90185r2_rule		High

Description
To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.

Description

To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., web servers and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Information systems use access control policies and enforcement mechanisms to implement this requirement. Access control policies include: identity-based policies, role-based policies, and attribute-based policies. Access enforcement mechanisms include: access control lists, access control matrices, and cryptography. These policies and mechanisms must be employed by the application to control access between users (or processes acting on behalf of users) and objects (e.g., devices, files, records, processes, programs, and domains) in the information system.

STIG	Date
Canonical Ubuntu 16.04 LTS Security Technical Implementation Guide	2018-07-18

Details

Check Text ( C-75209r1_chk )
Verify that an encrypted root password is set. This is only applicable on systems that use a basic Input/Output System BIOS. Run the following command to verify the encrypted password is set: # grep –i password /boot/grub/grub.cfg password_pbkdf2 root grub.pbkdf2.sha512.10000.MFU48934NJA87HF8NSD34493GDHF84NG If the root password entry does not begin with “password_pbkdf2”, this is a finding.

Check Text ( C-75209r1_chk )

Verify that an encrypted root password is set. This is only applicable on systems that use a basic Input/Output System BIOS.

Run the following command to verify the encrypted password is set:

# grep –i password /boot/grub/grub.cfg

password_pbkdf2 root grub.pbkdf2.sha512.10000.MFU48934NJA87HF8NSD34493GDHF84NG

If the root password entry does not begin with “password_pbkdf2”, this is a finding.

Fix Text (F-82133r1_fix)
Configure the system to require a password for authentication upon booting into single-user and maintenance modes. Generate an encrypted (grub) password for root with the following command: # grub-mkpasswd-pbkdf2 Enter Password: Reenter Password: PBKDF2 hash of your password is grub.pbkdf2.sha512.10000.MFU48934NJD84NF8NSD39993JDHF84NG Using the hash from the output, modify the "/etc/grub.d/10_linux" file with the following command to add a boot password for the root entry: # cat << EOF > set superusers="root" password_pbkdf2 root grub.pbkdf2.sha512.VeryLongString > EOF Generate an updated "grub.conf" file with the new password by using the following commands: # grub2-mkconfig --output=/tmp/grub2.cfg # mv /tmp/grub2.cfg /boot/grub2/grub.cfg

Fix Text (F-82133r1_fix)

Configure the system to require a password for authentication upon booting into single-user and maintenance modes.

Generate an encrypted (grub) password for root with the following command:

# grub-mkpasswd-pbkdf2
Enter Password:
Reenter Password:
PBKDF2 hash of your password is grub.pbkdf2.sha512.10000.MFU48934NJD84NF8NSD39993JDHF84NG

Using the hash from the output, modify the "/etc/grub.d/10_linux" file with the following command to add a boot password for the root entry:

# cat << EOF > set superusers="root" password_pbkdf2 root grub.pbkdf2.sha512.VeryLongString > EOF

Generate an updated "grub.conf" file with the new password by using the following commands:

# grub2-mkconfig --output=/tmp/grub2.cfg
# mv /tmp/grub2.cfg /boot/grub2/grub.cfg