## https://sploitus.com/exploit?id=E45DF219-8EC6-5DBD-9F86-77B97ED4AFB5
# cybersec-hw1
Homework #1 for *Introduction to Computer Security* at the University of Athens (Department of Informatics & Telecommunications).
A battery of binary-exploitation challenges hosted on the class HackCenter โ stack overflows, format strings, ROP, shellcode, and a JVM reverse-engineering puzzle. **Final score: 1230 points.**
## What's in this repo
- **[`challenges/`](challenges/)** โ one Markdown write-up per challenge. All in English. The interesting ones are summarized below.
- **[`programs/`](programs/)** โ the target binaries / source files for each challenge, preserved so the write-ups are reproducible.
## Highlights
### Favourite โ `argv0`
A canary-protected binary where the trick was to *use* the canary mechanism in our favour. Carefully crafted payload + correct offsets + assembly reading to figure out where the input gets stored โ and the canary check ends up printing the flag for us.
### Hardest
- **`choose_your_path`** โ I didn't have enough experience with the specific exploit class yet. Read about it, came back, solved it.
- **`fatty2`** โ finding shellcode that actually worked took most of the time. When it finally did, it dropped a shell with no privileges.
- **`syzygy`** โ first attempt was inserting NOPs by hand in GDB (terrible idea, very slow). Switched to **radare2** and solved it in a fraction of the time.
The full list of challenges with detailed solutions is in [`challenges/`](challenges/).
## Sequence
Part of a five-piece cybersecurity coursework cluster:
1. [cybersec-bn0](https://github.com/AlexTuring010/cybersec-bn0) โ class warm-up
2. [cybersec-hw0](https://github.com/AlexTuring010/cybersec-hw0) โ first homework
3. **cybersec-hw1** *(you are here)* โ HackCenter binary exploitation (1230 points)
4. [cybersec-hw2](https://github.com/AlexTuring010/cybersec-hw2) โ HackCenter web & crypto (3rd place)
5. [cybersec-hw3-chimera-agents](https://github.com/AlexTuring010/cybersec-hw3-chimera-agents) โ team CTF capstone