Mission Impossible

Hi mates,

Can someone of the 12 solvers of Mission Impossible contact me by DM to ask a question?

I have already solved the first part, but I am finding problems in solving the second.

Very much appreciated!!!
Best regards :slight_smile:

hey bro…

Same here. Got the first part and already have done some coding for the second but now I’m stuck a bit. Don’t want to spoil here too much. Could someone PM me, please? A hint is much appreciated :slight_smile:

Working on the second part of this as well. I think I know the attack method based on the name dropped in the initial decoded message and the error message the server gives when your “something” is incorrect.

Edit: Got it. I was correct about the attack method. Just had to use a different library. :wink:

I have no clue about how to even start with this challenge, anyone want to help me with a first push? Aiming to finish up these crypto challenges but I don’t even see how I would use this one huge number, assuming it is a number.

Hi, I’m on the second part of the challenge. I’m pretty sure about the method, but probably I’m doing something wrong.

The method takes “some time”… and the web service gets always closed after a while…

It is normal that the attack takes so long (and in this case how can I prevent the server for closing?) or I’m doing something wrong?


Did it, there was a bug in my script. It took some time anyway, but session was on enough to solve it.

I need serious help with this, I don’t know how to do the first bit

Anyone willing to share a hint on the first bit? Idea it is a xor encryption. Decrypting by trying to guess the first header and then guessing the rest of the content slowly while building a key - but it doesn’t seem to work with common headers

EDIT: Almost. Finally got the first bit.

I’ve tried a bunch of different things on the initial message and nothing seems to coming out of it. Would someone mind DM’ing me a hint? Not even the direct answer, but just a rough directly would be appreciated!

This seems to be one of the toughest challenges ever…as the name says though…

To anyone who solved the last part: How long did it take to decrypt the message? Oh man, it’s so slow…

EDIT: Finally got it. 19077 queries. OMG. I loved this challenge.

I could really use a push on the first part of this challenge. The usual methods don’t seem to work.

i have literally no idea of how to start the challenge, can smb DM me on how to start. I’ll rly appreciate it

Type your comment> @Ugi said:

I could really use a push on the first part of this challenge. The usual methods don’t seem to work.

I used a very basic, usual method for the first part. Consider all possible ways of analyzing the ciphertext.

I can’t decode the message file. Can someone give any clue?

Really liked this challenge. Techniques for both parts were new for me and I learned lots, although I lost my weekend :slight_smile:

This is a nice straightforward challenge. I probably made around 1.5 million queries before I stopped and verified my code and found a silly mistake ( I base64 decoded an initial hex encoded data ¯_(ツ)_/¯ ) After fixing the mistake it took about 19000 queries to find the flag.

I am curious how the challenge was constructed. The paper suggests that it should take around 1 million queries, but this challenge requires 19000 only. It is highly unlikely to be a random occurence. Is there a way to construct this kind of challenge with any given complexity, or was it a trial and error approach?

Took almost 3 hours on my slow machine :frowning: Had to code in a way to reconnect to new HTB docker since the instances kept dying on me

Hi all , cannot even start this challenge, outlook element won’t open, could anyone mp an hint plz ? ty