These are a collection of write-ups (found in https://ctftime.org/event/list/) that are both clearly written and have concepts and tools that apply to a broad range of CTF challenges.
- Writeup of Zero Width Hidden Text: https://ctftime.org/writeup/23379
- (Source: csaw CTF 2020 baby_mult) https://github.com/csivitu/CTF-Write-ups/tree/master/CSAW%20Quals%202020/Rev/baby_mult Tags: GDB