This executable can read data from local files.
This function can be performed by any unprivileged user.
ntpdate -a x -k /path/to/input-file -d localhost
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
ntpdate -a x -k /path/to/input-file -d localhost
This function is performed by the privileged user if the executable has the SUID bit set and the right ownership because the effective privileges are not dropped.
ntpdate -a x -k /path/to/input-file -d localhost