Vulnerability Discussion

RHEL 10 systems handling data that requires "data-at-rest" protections must employ cryptographic mechanisms to prevent unauthorized disclosure and modification of the information at rest.

Selection of a cryptographic mechanism is based on the need to protect the integrity of organizational information. The strength of the mechanism is commensurate with the security category and/or classification of the information. Organizations have the flexibility to either encrypt all information on storage devices (i.e., full disk encryption) or encrypt specific data structures (e.g., files, records, or fields).

Satisfies: SRG-OS-000405-GPOS-00184, SRG-OS-000185-GPOS-00079, SRG-OS-000404-GPOS-00183

Check

Note: If there is a documented and approved reason for not having data-at-rest encryption at the operating system level, such as encryption provided by a hypervisor or a disk storage array in a virtualized environment, this requirement is not applicable.

Verify RHEL 10 prevents unauthorized disclosure or modification of all information requiring at-rest protection by using disk encryption.

List all block devices in tree-like format:

$ sudo lsblk --tree
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sda 8:0 0 64G 0 disk
+-sda1 8:1 0 600M 0 part /boot/efi
+-sda2 8:2 0 1G 0 part /boot
+-sda3 8:3 0 62.4G 0 part
+-rhel-root 253:0 0 23G 0 lvm
¦ +-luks-9f886368-bf3e-4d17-86ed-a71dd6571bb4 253:2 0 23G 0 crypt /
+-rhel-swap 253:1 0 6.4G 0 lvm [SWAP]
+-rhel-var_tmp 253:3 0 3G 0 lvm
¦ +-luks-c98555c8-0462-4b97-9afa-6db8c4bfee3b 253:14 0 3G 0 crypt /var/tmp
+-rhel-var_log_audit 253:4 0 10G 0 lvm
¦ +-luks-4e45e1ad-5337-42c4-a19f-ee12ccc1d502 253:9 0 10G 0 crypt /var/log/audit
+-rhel-tmp 253:5 0 2G 0 lvm
¦ +-luks-2d7e1b45-73c4-4282-8838-15a897e0d04e 253:11 0 2G 0 crypt /tmp
+-rhel-home 253:6 0 10G 0 lvm
¦ +-luks-ca2261ed-7b00-4b7b-84cd-8cd6d8fa4b28 253:12 0 10G 0 crypt /home
+-rhel-var 253:7 0 5G 0 lvm
¦ +-luks-51150299-f295-4145-b8f0-ebe9c6dfd5a0 253:13 0 5G 0 crypt /var
+-rhel-var_log 253:8 0 3G 0 lvm
+-luks-c651f493-9fdc-4c6e-a711-0a4f03149661 253:10 0 3G 0 crypt /var/log

Verify that the block device tree for each persistent filesystem, excluding the /boot and /boot/efi filesystems, has at least one parent block device of type "crypt" and that the encryption type is LUKS:

$ sudo cryptsetup status luks-9f886368-bf3e-4d17-86ed-a71dd6571bb4
/dev/mapper/luks-9f886368-bf3e-4d17-86ed-a71dd6571bb4 is active and is in use.
type: LUKS2
cipher: aes-xts-plain64
keysize: 512 bits
key location: keyring
device: /dev/mapper/rhel-root
sector size: 512
offset: 32768 sectors
size: 48201728 sectors
mode: read/write
flags: discards

If there are persistent filesystems (other than /boot or /boot/efi) whose block device trees do not have a crypt block device of type LUKS, ask the administrator to indicate how persistent filesystems are encrypted.

If there is no evidence that persistent filesystems are encrypted, this is a finding.

Fix

Configure RHEL 10 to prevent unauthorized modification of all information at rest by using disk encryption.

Encrypting a partition in an already installed system is more difficult, because existing partitions will have to be resized and changed.

To encrypt an entire partition, dedicate a partition for encryption in the partition layout.