If the Trivial File Transfer Protocol (TFTP) server is required, the TOSS TFTP daemon must be configured to operate in secure mode.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-253102 | TOSS-04-040600 | SV-253102r1102131_rule | CCI-000366 | medium |
| Description | ||||
| Restricting TFTP to a specific directory prevents remote users from copying, transferring, or overwriting system files. | ||||
| STIG | Date | |||
| Tri-Lab Operating System Stack (TOSS) 4 Security Technical Implementation Guide | 2025-05-08 | |||
Details
Check Text (C-253102r1102131_chk)
Note: If TFTP is not required, it should not be installed. If TFTP is not installed, this is not applicable.
Check if TFTP server is installed with the following command:
$ sudo dnf list installed | grep tftp-server
tftp-server.x86_64 x.x-x.el8
If tftp.server is installed, verify the TFTP daemon is configured to operate in secure mode with the following command:
$ grep -i execstart /usr/lib/systemd/system/tftp.service
ExecStart=/usr/sbin/in.tftpd -s /var/lib/tftpboot
Note: The "-s" option ensures that the TFTP server only serves files from the specified directory, which is a security measure to prevent unauthorized access to other parts of the file system.
Fix Text (F-56505r1102130_fix)
Configure the TFTP daemon to operate in secure mode with the following command:
$ sudo systemctl edit tftp.service
In the editor, enter:
[Service]
ExecStart=/usr/sbin/in.tftpd -s /var/lib/tftpboot
After making changes, reload the systemd daemon and restart the TFTP service as follows:
$ sudo systemctl daemon-reload
$ sudo systemctl restart tftp.service