There's DTMF tones in the audio from 1:05ish - 1:18ish, decode those and convert the 2 digit ascii numbers to text to get the flag

tjctf{bruh_camel_240p}

If we open this up in a gcode editor, we can see a fake flag there. The hint hints at the movement speed of the arm, and so if we do a bit of research into this, we can see they are represented by "F" values. Therefore, we extract these from the gcode file. Most of them are either F10500 or F2400, but some of them appear to be quite small, and some even appear to be within the range of numbers for standard ASCII chars. Perhaps there is something hidden in those values... So, we filter out the F10500 and F2400 values. At the end of the output, we can see a list of values that appear to be within the ASCII number range, so I converted these numbers to ASCII text to get the flag.

F116
F106
F99
F116
F102
F123
F109
F52
F110
F121
F95
F108
F52
F121
F51
F114
F115
F125

Flag: tjctf{m4ny_l4y3rs}

We start with a .zip file. When we unzip, we get a directory called 0. It contains one file, 1.tar.bz2

If we decompress this file, we get a directory called 1, which contains 1.txt and another compressed file. This repeats.

The text files seem to contain tjctf{n0t_th3_fl4g}, I took a guess that at some level in this recursive compression has a .txt file that yields the flag.

This is relatively simple. Every file is either .kz3, .tar.bz2, or .tar.gz. We can use file extensions to detect which type of file it is, and then decompress. Script below(a bit bad, I'm aware) I unzipped up to directory 1 manually because it's different to the rest.

After running the script you'll be left with a file flags.txt. Majorly, flags.txt contains a bunch of ljctf{n0t_th3_fl4g}

Use ord(open()[x]) to read one byte at a time, and sleep for it's ascii value

tjctf{iTs_T1m3_f0r_a_flaggg}

This challenge was definitely one of the harder ones in the CTF, mainly because of it's deceiving point value, at only 5 points. The description doesn't provide any information at all, which was very strange, and the fact that the challenge was categorized as "Misc" also made it very confusing, as should the challenge not be OSINT if nothing at all is provided?

This ended up taking a very long time to figure out. Perhaps the title would give a bigger hint? It mentions Discord, which is a common text and voice messaging service used by gamers.

I myself, am not a gamer, so I wasn't too keen on the idea of registering at discord.com, but if I was going to get 5 points for it, I was going to do it nonetheless.

Registering however, was a challenge in itself.

The difficulty lies in that you have to put personal information in, but wait... Do I really trust a site like discord with my personal details?

Were these 5 points really worth it? I asked myself.

"Yes. Yes they are. We must beat our rivals Pwn to 0xE4!".

And so, reluctantly, I filled in my details, and added 2 Factor Authentication for safety.

These 5 points were going to be so worth it.

However, how was I to get into the server where the flag was?

I would need an invite link. But where was I to get that?

Well, I started by trying to OSINT the challenge creators, in the hopes that they would have left something in their social medias, but it ended up with no results, to my sadness.

I looked for minutes, hours, days for this link, but nothing showed up.

Eventually, I gave up and decided to come back to this challenge another day. I decided to look at other challenges.

What about that circle one? Or the difficult decryption one?

But still, there was a feeling in my heart.

A feeling that meant I would HAVE to get those 5 points.

After all, it could mean the difference between winning and losing...

One morning, while scrolling through the challenges, I noticed something rather interesting.

There was a logo that looked oddly familiar amongst the email, Facebook and Twitter logos.

At once I recognised what it was.

IT WAS THE DISCORD LOGO! Hovering over it, I saw it redirected to a discord.gg link.

Perhaps this was it?

Perhaps this was the link to join the discord?? With my right hand sweating and shivering, I moved my mouse towards the icon, and clicked.

For a moment... There was silence.

Nothing could be heard, except for the faint sound of rickrolls in the background, and the weird audio for arabfunny.

Suddenly, I was greeted with a page. "evanyeyeye invited you to join TJCTF".

This was it. Those 5 points were going to be mine, and we would crush Pwn to 0xE4 like twigs.

However, it turns out this was again, still not enough. The security of the server was set to very high, and I needed to pass a captcha.

"No problem!", I thought. "I can just use my OCR script!".

However, despite trying over 2 times to try and get the OCR script to work, I never managed to do it, and time was running out.

There were only 95 hours left in the CTF.

This needed to be quick.

We were running out of time.

This was an emergency.

Immediately I recruited help from our team's Asian, PotatoK. He was able to read the letters and numbers and so, after a long while of waiting, we got access to the server! Those 5 points were finally going to be ours! However, once again, due to the delicate crafting of this challenge by the creator, KyleForkBomb(who even is that guy), we were stopped in our tracks once again. "How many parts does this challenge have?", I thought to myself. I decided to go back to the challenge page, and luckily enough, there was a relevant hint!

"Type ?flag in chat"

So I proceeded to type in "?flag in chat", in the hopes that it would give me the flag, but after 5 seconds of me typing "?flag in chat" into notepad, it was clear that this was going nowhere. So, I kept on pushing. I found a shortcut for typing it as well, by simply CTRL-C to copy and CTRL-V to paste. However, even after a further 7 seconds of typing it, no flag was there. Where was this flag, and why was it so difficult just for 5 measly points? I had to beat Pwn to 0xE4. I had to.

After a few more seconds of trying to type "?flag into chat" into my notepad window, I decided to try and take the hint from another perspective. I decided to read the hint once more.

"Type ?flag in chat"

Ever since we discovered the hint, we had always interpreted it as 'Type "?flag i n chat"'. But what if it was meaning something else? For example, it could have meant 'Type "?flag" in chat'.

Now everything made sense.

The pain of trying to find the Discord link. The captcha which I had to get PotatoK to solve. The registering for the Discord account. It all made sense now. All the suffering we went through.

With palms still sweating, I slowly typed "?flag" into the #general chat.

There was no one else around as far as I could tell. I was going to crush Pwn to 0xE4.

I was going to get these points.

I was close, I could feel it.

I could definitely taste the flag.

I felt so close.

Once I typed "?flag" in chat, there was silence yet again.

I could feel the sense once again, just like when I clicked on the discord link.

A few seconds passed.

Then, I saw my message get deleted? Who could have done this? Was it the evil mind of the challenge creator? Was it... no... it couldn't be... Pwn to 0xE4???

Could they have done this in order to get the flag and the points before us?

This was a disaster.

We needed those points.

This was turning into a nightmare, and there were only 94 hours left in the CTF.

We needed a plan to take them down, and fast. We quickly retreated back to the Jackbox server in order to discuss.

This had to be done quick.

We would need to act fast.

Our plan was simple. We would just need to type the command, and the get output before Pwn to 0xE4 would have a chance to intervene.

Using my new techniques I learnt from Truly Terrible Why, and also the CTRL-C CTRL-V technique from earlier, I was set to get this flag. This was going to work.

I was going to get this flag, get those 5 points, and crush Pwn to 0xE4.

I could taste victory already, and those CTFTime points would definitely be ours.

We were almost ready to execute the plan.

This would be it.

The flag would be ours.

Those 5 points we worked so hard for.

Registering the account, finding the link, getting past the captcha, using the hint. All the pain and suffering would finally pay off.

We were ready to take on Pwn to 0xE4.

We waited for the perfect moment to strike, but we had to be extra careful, as we did not expect them last time...

The plan was in action! I pasted the command carefully, but swiftly, and awaited the response...

Yet again... silence...

Until...

We were able to retrieve a message link...

It appears this takes us to the announcements channel, which I scrolled through a couple times, but couldn't find anything of use.

Where was this flag, and why was this challenge only worth 5 points???

Then... something caught my eye...

It appeared to be... an image... with some text on it. The words looked familliar... especially the "tjctf" part...

Suddenly, I realised what this was.

This was the flag!! The very thing that took almost 2 minutes to find was right in front of us!!

I had to get PotatoK once again to read it for me, but we finally found the flag after a lot of sweat, pain, and effort.

Swiftly I wrote the flag down, and copied it into the flag box.

"Correct!" it read, and those 5 points were finally ours.

We would go on to get defeated by Pwn to 0xE4, as they solved Naughty, meaning that these 5 points made all the difference.

Thank you for making this one of the most difficult CTF challenges I have ever solved, and even though it was only worth 5 points, they were more than satisfying to get.

Flag: tjctf{circles_was_a_bad_challenge}

-@Willwam845

After analysing the random.randint i found that it was rigged (info by botters) so i just reversed what it done (with help from tony) and pieced it together - code below

tjctf{i5AJ0borFRenCx6342}

def getindex(a):
    out = []
    for i in a:
        if "{" in i:
            out.append(0)
        if "3" in i:
            out.append(1)
        if "4" in i:
            out.append(2)
        if "2" in i:
            out.append(3)
        if "}" in i:
            out.append(4)
    return out

with open("out","r") as f:
    out = f.read()
    f.close()
out = out.split("\n")[:-2]
out = [[x[i:i+5] for i in range(0, len(x), 5)] for x in out ]
stats = ""
for j in range(5):
    for i in out:
        a = getindex(i)
        print(a)
        stats += str((a.index(j)-j)%5)
print(stats) # 4 is common
counter = [0,0,0,0,0]
for i in stats:
    counter[int(i)] += 1

print(counter)
for k in range(5):
    for j in range(5):
        alpha = out[0][getindex(out[0]).index(k)]
        alpha2 = {}
        for i in alpha:
            alpha2[i] = 0

        for i in out:
            thing = i[getindex(i).index(k)]
            thing = thing[-1]+thing[:-1] # revshift by 4
            alpha2[thing[j]] += 1

        for i in alpha:
            print(i,alpha2[i],end=" ")
        print()

So, what a mess this was. Firstly, we started by performing a timing attack. That managed to get us quite a lot of things, but it was annoying having to wait 5 minutes for some results. So lets look for a better option. Looking at the hint, it says to think about I/O. Hmmm, ok. Connecting through netcat, it prints out "Imagine having a usable terminal". Ok, interesting. If we try and enter in a command, it doesn't output anything. Odd. We can probably assume that all our commands are being sent to /dev/null, where they just get wiped away. What if we could trick the connection to redirect our commands anywhere, instead of /dev/null. If we know that 2>/dev/null sends any errors there, we can redirect our output to the input as we're connected there, doing >&0. Once we've done some enum, we can use the name of the challenge "TT Why" (sounding like TTY) to spawn a tty shell, where we can run sudo -l (as password.txt has problem-user password) to see that we can run /usr/bin/chguser as root. Changing user, navigating to home folder, then to flag, we get flag.txt

>ls -alR ./ >&0
message.txt
password.txt

> cat message.txt
Man, I just sure wish I could impersonate other_user

> cat password.txt
Password for problem user: 1234qwer

tjctf{ptys_sure_are_neat}

So i was looking at the csv and thought "kek tf does this mean" but then i checked the range values for the csv and saw they were rly similar. i looked at the hint about tony stark and thought maybe i need to build an ai or some shit. woa kept telling me i was mental and had big confusion but i continued anyway. i built one (code below) and ran it (followed tutorial with adjustments for massive training data). the output it gave was in binary (like in training data). i converted to text and gave flag{mlWis_cool} but it looked like some bits were flipped so i changed it to flag{ml_is_cool} which is flag.

https://medium.com/technology-invention-and-more/how-to-build-a-simple-neural-network-in-9-lines-of-python-code-cc8f23647ca1

hlp = open("help.csv","r").read().split("\n")
hlp = [[int(y) for y in x.split(",")] for x in hlp]

flg = open("flag.csv","r").read().split("\n")
flg = [[int(y) for y in x.split(",")] for x in flg]


from numpy import exp, array, random, dot, set_printoptions, inf
set_printoptions(threshold=inf)

class NeuralNetwork():
    def __init__(self):
        self.synaptic_weights = 2 * random.random((10, 1)) - 1
    def __sigmoid(self, x):
        return 1 / (1 + exp(-x))
    def __sigmoid_derivative(self, x):
        return x * (1 - x)
    def train(self, training_set_inputs, training_set_outputs, number_of_training_iterations):
        for iteration in range(number_of_training_iterations):
            output = self.think(training_set_inputs)
            error = training_set_outputs - output
            adjustment = dot(training_set_inputs.T, error * self.__sigmoid_derivative(output))
            self.synaptic_weights = self.synaptic_weights + adjustment # fukin numpy being shit kek
    def think(self, inputs):
        return self.__sigmoid(dot(inputs, self.synaptic_weights))



neural_network = NeuralNetwork()

print("Random starting synaptic weights: ")
print(neural_network.synaptic_weights)
training_set_inputs = [[y/100 for y in x[1:]] for x in hlp]
training_set_outputs = [x[0] for x in hlp]

print(training_set_inputs[0],training_set_outputs[0])

for i,j in enumerate(training_set_inputs):
    neural_network.train(array([j]), array(training_set_outputs[i]).T, 10000) # gotta train individually or numpy gets triggered

print("New synaptic weights after training: ")
print(neural_network.synaptic_weights)

b = ""
for i,j in enumerate(flg):
    print("Considering new situation :",j)
    a = neural_network.think(array(flg[i]))[0]
    b += str(int(a))
    print(int(a))
print(b)