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V-269272

CAT II (Medium)

If the Trivial File Transfer Protocol (TFTP) server is required, the TFTP daemon must be configured to operate in secure mode.

Rule ID

SV-269272r1050154_rule

STIG

Cloud Linux AlmaLinux OS 9 Security Technical Implementation Guide

Version

V1R6

CCIs

CCI-000366

Discussion

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.

Check Content

Note: If a TFTP server is not installed, this requirement is Not Applicable.

Verify the TFTP daemon is configured to operate in secure mode.

Check if a TFTP server is installed with the following command:

$ dnf list --installed tftp-server

Installed Packages
tftp-server.x86_64        5.2-37.el9             @appstream

If a TFTP server is installed, check for the server arguments with the following command: 

$ systemctl cat tftp | grep ExecStart=

ExecStart=/usr/sbin/in.tftpd -s /var/lib/tftpboot

If the "ExecStart" line does not have a "-s" option, and a subdirectory is not assigned, this is a finding.

Fix Text

Configure the TFTP daemon to operate in secure mode with the following command:

$ systemctl edit tftp.service

Insert the following between the two sets of comments, making sure to add the "-s" option with a nonroot ("/") directory.

[Service]
ExecStart=
ExecStart=/usr/sbin/in.tftpd -s /tftp