Vulnerability Discussion

Restricting TFTP to a specific directory prevents remote users from copying, transferring, or overwriting system files.

Check

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

Check to see if a TFTP server has been installed with the following commands:

# yum list installed tftp-server
tftp-server.x86_64 x.x-x.el7

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

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

# grep server_args /etc/xinetd.d/tftp
server_args = -s /var/lib/tftpboot

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

Fix

Configure the TFTP daemon to operate in secure mode by adding the following line to "/etc/xinetd.d/tftp" (or modify the line to have the required value):

server_args = -s /var/lib/tftpboot