~/tools $ ./chmod --explain

Chmod Calculator

Flip permission bits or type an octal mode to see the symbolic form, including setuid, setgid, and sticky.

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PermissionsReadWriteExecuteOwnerGroupOtherSpecial
Symbolic
Command

Permissions in privilege escalation

On a Linux box, two searches find a large share of local privilege escalation paths. SUID binaries:find / -perm -4000 -type f 2>/dev/null, checked against GTFOBins. World-writable files and directories: find / -writable -type f 2>/dev/null, especially anything run by root or by cron.

Common modes

  • 644 regular files, 755 directories and executables.
  • 600 private keys. SSH refuses keys that other users can read.
  • 1777 shared temp directories such as /tmp.