n30np14gu3's WTF(Where This Flag)

Author:
n30np14gu3

Language:
C/C++

Upload:
2020-03-29 09:04

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Platform:
Windows

Difficulty:
4.0

Quality:
4.0

Arch:
x86

Downloads:
236

Size:
32.00 KB

Writeups:
1

Comments:
11

Description

New CrackME. There are three flags in this program. The first flag is in the maze. You will get the second flag by guessing the decryption password. The third flag is hidden in the depths of the program. Good luck to all)

Labels ?

String / data encryption Control-flow obfuscation Spaghetti / junk-branch Anti-disassembly Opaque predicates

Comments (11)
Writeups (1)

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jeffli6789 on 2020-04-07 01:18: [Click to reveal]

n30np14gu3 on 2020-04-07 10:04: jeffli6789, nice 2 flags left

jeffli6789 on 2020-04-12 11:50: @author, I saw another flag text in the strings. But I cannot find a way to trigger it in the maze. Btw, I found some trace of the third flag, but I cannot figure it out. Do you mind my getting in touch with you?

n30np14gu3 on 2020-04-12 22:19: jeffli6789, [HINT] the path out of the maze is the flag, just encoded in a certain way.

jeffli6789 on 2020-04-13 11:20: I actually solved the maze. And in the end it prints a line to ask me where is the flag. So I suppose you mean the solution path of the maze somehow form a solution? Btw, is this about the third flag or the first one?

jeffli6789 on 2020-04-13 11:22: I am curious whether there is a way to let the program print the "nice jump" flag, or it is designed to be find in the strings and that is all of it?

jeffli6789 on 2020-04-13 11:39: It also seems to me there is no maze game logic in the program? It just compares the user input to a fixed solution path. I used turtle to draw the path out it it seems using exploring the maze.

jeffli6789 on 2020-04-13 12:00: Let me rephrase it a little bit so you do not get confused: 1). I see a string in the binary that satisfies the flag format. I will call it "nice jump" flag. My first question is whether this is the first flag? And if it is, is there an input that can trigger the program to print it to the console? Or It is just supposed to be found by looking at the strings. 2. I already found out the correct solution to the maze. And it seems to me there is no maze logic. It just compares the user input with this fixed solution. However, in the end, it asks "where is the flag", so I suppose this maze solution is not really helpful. Again, I wish to find an input that can print the nice jump flag, but failed. 3. For the third flag, I explored all of the functions in the binary but I am not sure whether any execution

n30np14gu3 on 2020-04-13 14:33: I don't write very well in English, but I'll try to explain. [MAZE TASK] The flag is the way out of the maze. That is, a string that is an output, after entering which the message appears on the screen:"... where is flag?". It's just encoded in a special way. [SECRET TASK] Line "...nice jump" is a hint to the place where there is a transition to the next secret function. The pass code to the secret location looks like this .text:xxx push eax SECRET_DATA .text:xxx xor eax, 1358h .text:xxx push ebx .text:xxx xor eax, ebx .text:xxx xor ebx, eax .text:xxx xor eax, eax .text:xxx pop ebx .text:xxx pop eax --- Unfortunately, the solution never uploaded to the site, so here is the link. https://yadi.sk/d/u-EvDNLH4rLv4Q

jeffli6789 on 2020-04-13 15:12: Thanks for the explanation. I will check it out!

jeffli6789 on 2020-04-13 15:36: flag 3 is nicely hidden! I actually defined that function but I did not pay any attention to it!

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Solution by n30np14gu3 on 2020-04-07 10:07:
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n30np14gu3's WTF(Where This Flag)