Disk Encryption of Data on FortiSIEM Supervisor

The steps below show how to encrypt /cmdb, /svn, and /data disks on a FortiSIEM supervisor VM node with local disk for EventDB (/data). If you are using NFS or Elastic storage, you must perform additional steps for the actual data directories on these servers in addition to supervisor (/cmdb, /svn).

Note 1: We do not recommend encrypting the root disk which presents an operational challenge during boot up to provide a passphrase. The root disk contains binaries and some internal system and application logs, not data.

Note 2: Disk encryption key management is an operational challenge. If you want strong security, then you must protect encryption keys with a passphrase and that requires a human to type them and mount the “opened” disks. The less secure alternative is to use keys that are not protected by a passphrase and stored in a file on the root partition.

Note 3: The cryptsetup command is not included in FortiSIEM. To verify if the package is installed, run the following command:

dnf search cryptsetup

To install, run the following command:

dnf install cryptsetup -y

It is best to perform these steps on a fresh installation prior to initializing the product. This avoids the need for additional disks. If you have to perform these on an existing installation of FortiSIEM, then you must have additional disks of the same capacity to encrypt and copy the data to it. Here is a quick overview of the steps:

1. Import the latest FortiSIEM VA image on one of the supported platforms.
2. For each disk, (/cmdb, /svn, /data) complete the following steps:
   1. Unmount the filesystem.
   2. Wipe the filesystem of exiting filesystem and partition table.
   3. Setup a LUKS formatted disk which prompts you for a passphrase that protect the encryption keys in Slot 0 – Your disk is now encrypted.
   4. Add another LUKS key into Slot 1 and save this into a file on /etc. (There are a total of 8 key slots).
   5. Open the encrypted disk after providing a passphrase for further operations which provides a /dev/mapper/XYZ device.
   6. Create an entry in /etc/crypttab which will open the encrypted disk using the Slot 1 key file you saved above at boot time.
   7. Create an ext4 filesystem on the opened disk in /dev/mapper/XYZ.
   8. Create an /etc/fstab entry to mount the opened disk above to a named path (/cmdb, /svn, or /data as the case may be).

Detailed Steps to Encrypt Disk Data

Step 1: Import VA VM image and start the VM

Import VA VM image on one of the supported platforms as per user guide. Add a 4th /data disk if you plan on using local storage. Then, start the VM. Once you login by using ssh, run the df -h command to list the mounted filesystems. You will see both /cmdb and /svn, for example:

 [root@localhost ~]# df -h 
  Filesystem      Size  Used Avail Use% Mounted on
  /dev/sda3        55G  6.7G   46G  13% /
  tmpfs           7.8G     0  7.8G   0% /dev/shm
  /dev/sda1       124M   43M   76M  36% /boot
  /dev/sdb1        60G  180M   56G   1% /cmdb
  /dev/sdc1        60G  180M   56G   1% /svn
  [root@localhost ~]#

If you had added a 4th disk for /data, you should be able to list this as well by using the fdisk command. These device names will vary on other platforms such as AWS, KVM, etc.

  [root@localhost ~]# fdisk -l /dev/sdd
  Disk /dev/sdd: 53.7 GB, 53687091200 bytes
  255 heads, 63 sectors/track, 6527 cylinders
  Units = cylinders of 16065 * 512 = 8225280 bytes
  Sector size (logical/physical): 512 bytes / 512 bytes
  I/O size (minimum/optimal): 512 bytes / 512 bytes
  Disk identifier: 0x00000000 

Step 2: Unmount /cmdb filesystem

Use the umount command to unmount the CMDB filesystem, for example:

umount /cmdb

Step 3: Wipe the /cmdb disk of previous filesystem and partition info

Use the wipefs command to clear the existing filesystem and partition information from the CMDB disk, for example:

 [root@localhost ~]# wipefs --all /dev/sdb1
  2 bytes [53 ef] erased at offset 0x438 (ext3)
  [root@localhost ~]# wipefs --all /dev/sdb  
  wipefs: WARNING: /dev/sdb: appears to contain 'dos' partition table

Step 4: Setup LUKS format disk encryption for /cmdb disk

When you run the cryptsetup luksFormat command, you must provide a passphrase that protects the encryption key for the disk. This key is stored in Slot 0 of the keys.

  [root@localhost ~]# cryptsetup luksFormat /dev/sdb

  WARNING!

  ========

  This will overwrite data on /dev/sdb irrevocably.
  Are you sure? (Type uppercase yes): YES
  Enter LUKS passphrase:
  Verify passphrase:

There are a total of 8 slots for additional keys which can be used to provide multiple admins the ability to unlock the disks or can be used for periodic rotation of keys. The following command can be used to dump information about different slots.

  [root@localhost ~]# cryptsetup luksDump /dev/sdb|grep Slot  
  Key Slot 0: ENABLED
  Key Slot 1: DISABLED
  Key Slot 2: DISABLED
  Key Slot 3: DISABLED
  Key Slot 4: DISABLED
  Key Slot 5: DISABLED
  Key Slot 6: DISABLED
  Key Slot 7: DISABLED

Step 5: Add a new key to LUKS disk for /cmdb

Use the cryptsetup command with the luksAddKey option to add the LUKS key for the CMDB disk, for example:

cryptsetup luksAddKey /dev/sdb /etc/enccmdbkey

Note: /etc/enccmdbkey is not a file that is included. If cryptsetup throws an error stating that the file is missing, run the following:

touch /etc/enccmdbkey

Enter any passphrase.

If you enter the cryptsetup command with the luksAddKey option again, you will see that two slots have enabled keys. Slot 0 contains the key that was generated when you first created the encrypted disk. Slot 1 contains the new key you just added above which was copied to a file. Additional commands for LUKS keys are in this document.

  [root@localhost ~]# cryptsetup luksDump /dev/sdb|grep Slot
  Key Slot 0: ENABLED
  Key Slot 1: ENABLED
  Key Slot 2: DISABLED
  Key Slot 3: DISABLED
  Key Slot 4: DISABLED
  Key Slot 5: DISABLED
  Key Slot 6: DISABLED
  Key Slot 7: DISABLED

Step 6: Open the encrypted CMDB disk

Use the cryptsetup command with the luksOpen option to open the encrypted CMDB disk, for example:

cryptsetup luksOpen /dev/sdb encryptedCmdb --key-file /etc/enccmdbkey

Step 7: Configure automatic encrypted disk “open” at boot up

Create an entry in /etc/crypttab which will open the encrypted disk using the Slot 1 key file you saved above at boot time.

  echo "encryptedCmdb /dev/sdb /etc/enccmdbkey luks" > /etc/crypttab

Step 8: Create an ext4 filesystem on the “opened” encrypted disk

Use the mkfs.ext4 command to create an ext4 file system on the disk, for example:

  [root@localhost ~]# mkfs.ext4 /dev/mapper/encryptedCmdb    
  mke2fs 1.41.12 (17-May-2010)
  Filesystem label=
  OS type: Linux
  Block size=4096 (log=2)
  Fragment size=4096 (log=2)
  Stride=0 blocks, Stripe width=0 blocks
  3932160 inodes, 15728128 blocks
  786406 blocks (5.00%) reserved for the super user
  First data block=0
  Maximum filesystem blocks=4294967296
  480 block groups  
  32768 blocks per group, 32768 fragments per group
  8192 inodes per group
  Superblock backups stored on blocks:
  32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
  4096000, 7962624, 11239424
  Writing inode tables: done
  Creating journal (32768 blocks): done
  Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 37 mounts or 180 days, whichever comes first. You can override this by using the tune2fs -c or -i command.

Step 9: Replace /etc/fstab entry to mount the encrypted disk instead of the original

Enter these commands to mount the encrypted disk instead of the non-encrypted disk.

  [root@localhost ~]# grep cmdb /etc/fstab
  /dev/mapper/encryptedCmdb /cmdb ext4 defaults,nodev 0 1

Step 10: Remount new /cmdb

Use the mount and df commands to remount the new CMDB disk, for example:

  [root@localhost ~]# mount /cmdb
  [root@localhost ~]# df -h /cmdb
  Filesystem     Size  Used Avail Use% Mounted on
  /dev/mapper/encryptedCmdb  
  59G   52M   56G   1% /cmdb

Steps to Encrypt Disk Data for /svn

Encrypting disk data for /svn is very similar. Replace the device names, encryption key file name, and device mapper device names appropriately.

Steps to Encrypt Disk Data for /data (local)

Encrypting disk data for local /data is very similar. Once you have created the encrypted disk, do not create the filesystem. That will be done when you setup storage. You must provide a /dev/mapper/encryptedData device name in the storage setup.