One Time 'Bad' - AngstromCTF 2020

[wrthh]

The flaw is on the random seed, it uses time.time() which is totally fine but then it wrapped using int(), that makes the time.time() value becomes rounded into a whole integer, then we can use the same genSample() script with the seed
int(time.time())+1 and it will be the same as the service seed when you connect after you generate the sample

[hallgowrt]

I was literally banging my head for this... so simple! Thanks will look for such things onwards...

[SoujanyaCS]

you always show us the most interesting things 😍

[merzoukbensellouaahmedyass]

I think the weakness is in seeding the random one time when the connection is established, so you'd request a samples, get the correct seed (since you have a small interval of mili-seconds from the connection to getting the prompt), and know what the next randint will be and get the flag.
You're way is more simpler!!

[ripmeep]

Great video :) can't wait to see more content

[abiworldseccentric]

I appreciate your fast movement man .. good

[zaxioms]

That makes so much sense. The probability of guessing correctly with A is just 1/(30*26) = 1/780. What a good solution.

[mattfowler]

Good morning I'm having trouble keeping my eyes open.

[docmalitt]

Hi John, difficult to refuse such a polite invite to smash YouTube algorithm for fun (us) and profit (you, hopefully ); btw I do have a weird idea. You have lately been pretty busy with different certifications and pwned all the good ones. Old continent is in lockdown but this might be the perfect time to “upgrade” ones CV. (Admittedly we are lucky to be in this branch and have so far pretty secure jobs while whole countries are switching to working online) but it would be nice to see proper response from major companies offering significant discounts for at least some certifications. While I do appreciate all those 10-15% off “insert-color” Friday, a Corona50%OFF discount would be much more interesting and accessible for this pretty major disruption in our lives. (Sorry if I’m a bit of topic but it’s been on my mind last few days). Cheers

[abdiwahabahmedomar]

nice keep doing ctf no more netflix 🎉🎉✌

[gwnbw]

Hello how many cups of coffee did you have this morning?

[fail]

If you didn't like the video press the dislike button twice... LOL

[Wizatek]

Press the dislike button twice, haha good one