We-are-in-the-Endgame-Now

We are in Endgame now (PWN)

To be honest this also includes small ammount of reverse engineering to find the logic of the program, as this whole challenge is about Logic Overtake so we need to win the game by using it's own logic.

I would say this is easy in both domain (reverse and pwn) but together it might fall in medium difficulty level.

What we get

We get a Executable File named endgame. Here are the details :

endgame: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=b2c19aa34961bd1fc9251652dc2279a61a2c5e85, for GNU/Linux 3.2.0, not stripped

Understanding the Goal

After playing around with the binary we get the following logic :

• We need to work to earn money
• We need money to buy spidy suite from Mr. Stark (idk why)
• We can only input 3 charters in Work hour field (max : 999)
• We get paid $1 per hour (o_o)
• Going home will decrease 1 level from our suite
• We need suite level > 5 to defeat thanos
• In shop only 5 levels are available.

After some sweet reverse engineering

• The hours only accepts 3 digits but also e i.e. 1e9 = 1*10^9 is acceptable

• The home function only does a-b AND DO NOT NORMALISE INPUT

• If suit level > 5 we win

How to win

• I put 9e9 in the hours input that gave me 9*10^9$ (be rich just like that)
• Bought Level 5 Suit
• Went home to rest for -5 hours, that will change suite level to 5-(-5) = 10

So executing this will give us enough money to buy lvl5 armor and then we can degrade it to lvl 10 lmao and then defeat thanos (if that was this easy)

Here are Screen Shots for MCU to learn.

FLAG

After this we got our flag (when we executed this in challenge server).