---
# System prepended metadata

title: "NCtfU - 5/13 (PWN \U0001F383) (A205)"
tags: [nctfu2021]

---

# NCtfU - 5/13 (PWN 🎃) (A205)

###### tags: `nctfu2021`
[toc]
## 錄影連結

## 會參加
- Onebone
- idisused
- yenchia(online)
- maple (晚到)
- 石頭(線上, 晚)

## 講者筆記
- https://hackmd.io/4jEjl7FlSqqiTi8HGErfSg#heap

## 共筆

- man7.org
- stdlib.h & unilib.h
- xinfo (look memory)
- 0x21000 (dynamic allocate memory initial space)
    - malloc
    - printf & scanf (128kb mmap)
- free chunck save fd(foward), bk(back)
- tcache (first look before chunk size:0x20-0x410)
    - every bin store 7
    - one way link list(FILO)
    - fd point to data 
- fastbin
    - fd point to meta data
- https://github.com/shellphish/how2heap
- 