If the Trivial File Transfer Protocol (TFTP) server is required, TOSS 5 TFTP daemon must be configured to operate in secure mode.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-282682 | TOSS-05-000208 | SV-282682r1201337_rule | CCI-000366 | high |
| Description | ||||
| Restricting TFTP to a specific directory prevents remote users from copying, transferring, or overwriting system files. Using the "-s" option causes the TFTP service to only serve files from the given directory. | ||||
| STIG | Date | |||
| Tri-Lab Operating System Stack (TOSS) 5 Security Technical Implementation Guide | 2026-04-01 | |||
Details
Check Text (C-282682r1201337_chk)
Note: If TFTP is not required, it should not be installed. If TFTP is not installed, this is not applicable.
Determine if TFTP server is installed using the following command:
$ sudo dnf list installed | grep tftp-server
tftp-server.x86_64 x.x-x.el8
Verify the TFTP daemon, if tftp.server is installed, is configured to operate in secure mode using the following command:
$ grep -i execstart /usr/lib/systemd/system/tftp.service
ExecStart=/usr/sbin/in.tftpd -s /var/lib/tftpboot
If TFTP is installed and is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.
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-87148r1201336_fix)
Configure the TFTP daemon to operate in secure mode using 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:
$ sudo systemctl daemon-reload
$ sudo systemctl restart tftp.service