mcfx's blog - HackTM CTF Quals 2020 Writeup 的评论

h1st

h1st — Tue, 07 Apr 2020 09:46:09 +0800

sto driver

wxh010910

wxh010910 — Tue, 10 Mar 2020 12:29:23 +0800

orz mcfx god

Trung

Trung — Wed, 04 Mar 2020 00:45:10 +0800

I didn't know A* algo, check it rn! Thank you so much!

admin

admin — Sun, 01 Mar 2020 04:24:02 +0800

2. Since we can find these matched results, such bfs(or maybe A*) algorithm will lead to a low score situation, that means y is very large, and that's what we need for the answer.

admin

admin — Sun, 01 Mar 2020 04:22:14 +0800

In u(x,y), x is current length of input diff, y is current length of matched result, and u(x,y) gives a resonable score of them - to make the result match as much as possible.

Trung

Trung — Mon, 17 Feb 2020 16:12:58 +0800

Hi there, I have read baby_bear writeup, but I can't understand somethings on your exploit code:
1.You use u(x,y) to calculate for the order of the heap, what is the base of that ?
2.How could you use bitxor to find next bytes? (algorithms or somethings else?)
Thanks for your help!
Sorry for those previous noised cmt.

Trung

Trung — Mon, 17 Feb 2020 15:52:29 +0800

Hi there, I have read baby_bear writeup, but I can't understand somethings on your exploit code:
1. def u(x,y):
return x-y*2.5
You use u(x,y) to calculate for the order of the heap, what is the base of that ?
2. def bitxor(s,x):
xt=x>>3
return s[:xt]+bytes([s[xt]^(1

Trung

Trung — Mon, 17 Feb 2020 15:37:20 +0800