https://denarzai.github.io/CTF writeups, HackTheBox walkthroughs, and cybersecurity notes by Muhammad Subhan — BS Cybersecurity student at FAST NUCES Islamabad. 2026-07-04T16:21:04+05:00 Muhammad Subhan https://denarzai.github.io/ Jekyll © 2026 Muhammad Subhan /assets/img/favicons/favicon.ico /assets/img/favicons/favicon-96x96.png 2026-07-02T05:09:00+05:00 2026-07-02T05:09:00+05:00 https://denarzai.github.io/posts/tryhackme-presecurity-module-2/ Muhammad Subhan

Overview Module 2 of TryHackMe’s Pre-Security path covered the foundational concepts of IT and computing across four rooms. Most of this was conceptual rather than hands-on — building the mental model of how computer systems are structured and how they communicate before getting into security specifics. Room 1 — Core Computer Components and the Boot Process The first room covered what’s phys...

2026-07-01T01:05:00+05:00 2026-07-01T01:05:00+05:00 https://denarzai.github.io/posts/bandit-level-20-21/ Muhammad Subhan

The Goal A setuid binary called suconnect connects to a port on localhost. If it receives the correct password for bandit20, it sends back bandit21’s password. The challenge: you need a listener running and ready before suconnect connects to it — both things have to happen at the same time in one terminal. What I Did Listed the home directory and ran the binary without arguments: bandit20@b...

2026-06-30T03:00:00+05:00 2026-06-30T03:00:00+05:00 https://denarzai.github.io/posts/bandit-level-19-20/ Muhammad Subhan

The Goal Use a setuid binary in the home directory to read the password file for bandit20 — a file that bandit19 cannot access directly. What I Did Listed the home directory and found a binary called bandit20-do. Ran it without arguments first as the level suggested: bandit19@bandit:~$ ./bandit20-do Run a command as another user. Example: ./bandit20-do whoami Tested it with whoami to co...

2026-06-30T02:40:00+05:00 2026-06-30T02:40:00+05:00 https://denarzai.github.io/posts/bandit-level-18-19/ Muhammad Subhan

The Goal The password is in a file called readme in the home directory. The problem: .bashrc has been modified to log you out immediately when you SSH in, before you can run any commands. What I Did Normal SSH login would drop me straight back out because of the modified .bashrc. The fix is to tell SSH to run a specific command directly instead of starting an interactive shell: ssh bandit18...

2026-06-30T02:20:00+05:00 2026-06-30T02:20:00+05:00 https://denarzai.github.io/posts/bandit-level-17-18/ Muhammad Subhan

The Goal Two files in the home directory: passwords.old and passwords.new. Both contain hundreds of lines. One line has changed between them. Find the changed line in passwords.new — that’s the password. What I Did Listed the directory and saw both files. Opened both with cat to understand the structure — both had roughly 100 lines of what looked like passwords. Tried a few wrong approaches...