0Pricing
Cyber Security Academy · Lesson

File Permissions and Ownership

Master chmod, chown, sticky bit, SUID/SGID, and how permissions prevent unauthorized access.

Why Permissions Matter

File permissions control who can read, write, or execute a file. Misconfigured permissions are one of the most common causes of privilege escalation and data breaches.

The Permission String Explained

When you run ls -la, each file shows a 10-character permission string like -rwxr-xr--. Break it into: file type, owner permissions, group permissions, others permissions.

$ ls -la /etc/passwd
-rw-r--r-- 1 root root 2847 Jan 10 10:00 /etc/passwd
# -  = regular file
# rw- = owner (root) can read+write
# r-- = group can read only
# r-- = others can read only

All lessons in this course

  1. File Permissions and Ownership
  2. User and Group Management
  3. SSH Hardening and Key-Based Auth
  4. iptables and UFW Firewall Rules
← Back to Cyber Security Academy