# TU CTF 2018 - hardDOS
## DescriptionPaying attention is mitey important! (Difficulty: Hard)
nc 18.216.100.42 12345
## SolutionThis challenge is similar to [easyDOS](../easyDOS), we have to find the correct commands and arguments.
Also in this case we have to answer some questions before reaching the real challenge.
![msg1](./img/msg1.png)
Let's just pick one of them.
![msg2](./img/msg2.png)
Of course yes!
Now the real challenge starts. Apparently `THE MITE` is giving us some hints.
`"THE MITE: First thing's first. What's even in here?"`
This step was fairly easy, `ls` is working! We got a list of files and a new hint.
`"THE MITE: Alright, seems like a standard DOS installation. One of these files must to have something in it."`
We lost quite a lot of time before discovering that the correct command was `file`. Knowing that we iterate over all files.
`"THE MITE: Hey now, GRAPHICS.COM should be a DOS executable!"`
So `GRAPHICS.COM` is the file we are interested in. Eventually one of us tried to do `strings GRAPHICS.COM`, which gave us the content of the file and the flag!
```    TUCTF{4LW4Y5_1NF3C7_7H353_19742_BY735}```
## Code[flag.py](./flag.py)
## CascadeNote that the server was infected by [Cascade](http://malware.wikia.com/wiki/Cascade). Once connected, we only had three minutes before it hits.