Ubuntu operating systems handling data requiring "data at rest" protections must employ cryptographic mechanisms to prevent unauthorized disclosure and modification of the information at rest.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-238335	UBTU-20-010414	SV-238335r654180_rule		Medium

Description
Information at rest refers to the state of information when it is located on a secondary storage device (e.g., disk drive and tape drive, when used for backups) within an operating system. This requirement addresses protection of user-generated data, as well as operating system-specific configuration data. Organizations may choose to employ different mechanisms to achieve confidentiality and integrity protections, as appropriate, in accordance with the security category and/or classification of the information.

Description

Information at rest refers to the state of information when it is located on a secondary storage device (e.g., disk drive and tape drive, when used for backups) within an operating system. This requirement addresses protection of user-generated data, as well as operating system-specific configuration data. Organizations may choose to employ different mechanisms to achieve confidentiality and integrity protections, as appropriate, in accordance with the security category and/or classification of the information.

STIG	Date
Canonical Ubuntu 20.04 LTS Security Technical Implementation Guide	2022-12-06

Details

Check Text ( C-41545r654178_chk )
If there is a documented and approved reason for not having data-at-rest encryption, this requirement is Not Applicable. Verify the Ubuntu operating system prevents unauthorized disclosure or modification of all information requiring at-rest protection by using disk encryption. Determine the partition layout for the system with the following command: #sudo fdisk -l (..) Disk /dev/vda: 15 GiB, 16106127360 bytes, 31457280 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: gpt Disk identifier: 83298450-B4E3-4B19-A9E4-7DF147A5FEFB Device Start End Sectors Size Type /dev/vda1 2048 4095 2048 1M BIOS boot /dev/vda2 4096 2101247 2097152 1G Linux filesystem /dev/vda3 2101248 31455231 29353984 14G Linux filesystem (...) Verify the system partitions are all encrypted with the following command: # more /etc/crypttab Every persistent disk partition present must have an entry in the file. If any partitions other than the boot partition or pseudo file systems (such as /proc or /sys) are not listed, this is a finding.

Check Text ( C-41545r654178_chk )

If there is a documented and approved reason for not having data-at-rest encryption, this requirement is Not Applicable.

Verify the Ubuntu operating system prevents unauthorized disclosure or modification of all information requiring at-rest protection by using disk encryption.

Determine the partition layout for the system with the following command:

#sudo fdisk -l
(..)
Disk /dev/vda: 15 GiB, 16106127360 bytes, 31457280 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 83298450-B4E3-4B19-A9E4-7DF147A5FEFB

Device Start End Sectors Size Type
/dev/vda1 2048 4095 2048 1M BIOS boot
/dev/vda2 4096 2101247 2097152 1G Linux filesystem
/dev/vda3 2101248 31455231 29353984 14G Linux filesystem
(...)

Verify the system partitions are all encrypted with the following command:

# more /etc/crypttab

Every persistent disk partition present must have an entry in the file.

If any partitions other than the boot partition or pseudo file systems (such as /proc or /sys) are not listed, this is a finding.

Fix Text (F-41504r654179_fix)
To encrypt an entire partition, dedicate a partition for encryption in the partition layout. Note: Encrypting a partition in an already-installed system is more difficult because it will need to be resized and existing partitions changed.