Hello, world.

This is CS 50 on Twitch.

My name is Colt in Ogden and we're joined today again My ci's fifties.

Nick Wong.

Hello.

Good to see you on the street again.

What are we talking about?

Supposed to come back?

We're talking about C.

T s.

I saw some discussions in the chat, which was, you know, what is a c t f?

It's cool.

The fridge getting that's not at all what it stands for.

It stands for capture The flag on that is not.

Technically, we were joking a little bit earlier than it sounds very, really nontechnical for something that is somewhat technical.

But basically there's these kind of flags.

They're basically the strings of random characters or maybe meaningful characters or phrases.

They're hidden somewhere, maybe in a system or maybe as, like, some sort of abstracts like reward for solving puzzles.

And you have to go find him, eh?

So what we're doing today is a type of C T f, which is your get handed a system.

And there may be some vulnerabilities or kind of like puzzles they have to solve.

And when you solve them, you get these flags and the flags are actually, in our case.

Passwords to new levels.

Eso each level is actually a user on a UNIX on a into system.

And after we get a flag, we can use it as a password before the next level are the next user you mentioned there.

This is particularly server based CT, but there are filed based versions of Google's that they put out, and I think maybe another one that I'm missing up.

I think PICO, 2017 did have some wild stuff to it.

Big, I think, covers a wide range of like category where they have some like shh interfaces.

Sometimes it's just a puzzle like just decrypt this.

Some of them are like, Can you explain how this works, or can you pick the right answer?

Some of them are like, Here's a file.

Can you figure out what its meaning is?

And it's like a pea cap files Heathrow through wire shark or something on S O.

P.

C.

P.

D.

See if there's a really good job of covering a wide range of difficulties and also just types.

I like to focus on the box based ones just because my background is a little bit more tighter.

Security focus.

So it tends to be focused like a machine.

What vulnerabilities in house.

How do you figure it correctly?

Hopefully, people.

So is our school's cold.

As Lee Tuchman Billick yours and Texas affects to see.

I'm not sure I'm pronouncing that correctly, but thanks everybody.

So much for tuning in, uh, unrelated to see temps or anything.

Really content wise.

Today's episode is number 50 and this is this is a CS 50 show.

This is CS 50 on Twitch.

Yeah, and actually gonna take this opportunity to announce that we're actually rebranding.

So we are moving away from the name CS 50 on Twitch, given that we publish or we produce our content not only for YouTube and none for twitch, Facebook and YouTube and other platforms.

And so we're actually transitioning from strictly being seized 50 on twitch to being CS 50 alive in the chapel window.

In a little bit, it looks like it's kind of blocking that just a little bit.

Someone who's just a little bit.

But some folks might remember this from years prior, where we actually had a new show this wanted this back in, like 2013.

24.

It's a little before my way.

Current events show was 50 live, and David and Doug and others would come on and actually didn't show on Episode two of the robot.

Uh, but we dance the Macarena, actually, which is across wild.

But there we did this show based on current events and, you know, just given time constraints were unable to really bring the show.

We weren't able to do it as consistent as we wanted to.

So even that we've been doing this show and it's live broadcast multiple platforms.

They were sweet.

Francis need to see his 50 live.

Oh, so thank you for being upset.

50.

Thanks for being on this episode and for being on so many toes prior to with that announcement, I guess.

Why don't we?

Why don't we just get right into it?

I also realize that we're in the You think this is from my freshman year to this for a little while Because a lot of seats 50 in the air and I feel like I can feel it.

I can feel it.

You couldn't tell?

This is Let me, um, go ahead and transition to what I think.

I think yours is in right now.

So you that way see your gold back or show there.

That which is a remind people how again to get a show.

That's kind of like, Yeah.

So this is a program.

We'll go and find it.

This is the program.

See, Matrix, which looks like this normally on Max I can pipe.

That's a law cat.

Oops, sorry.

Can't type life when it gets this beautiful rainbow color.

I found that unlike a been two systems, I wasn't necessarily able Thio get this piping effect Quite right.

So there is kind of a bummer with that, but if you can figure it out I tried piping all of their like, varying standard outs and standard heirs to one output and see if I could get it Thio rainbow Color it.

But I'm not entirely sure how.

See matrix and roll cat work on the bottom are, uh, back in.

So however that ended up happening, it works on so Essex's bash.

This is fine.

It's, you know, it's an upgrade from from the people.

You agree.

I'm also a huge fan of looking my terminals.

My bash has a little kind of cute smiley face.

Hey, really not interesting for functionality.

But if I only type of command that doesn't exist, it tells me that I had an error, and you have All right.

Yeah, I just kind of do What if I go back Something that works, Then I get my smiley face back.

Giving like this is an important thing.

Exactly.

Just like keeping my terminal personal.

Uh, and you don't get a lot of very nice visual feedback with the Terminator.

Defoe Not not Norway.

A lot of times, things will succeed by giving you nothing.

Actually, yeah, they failed by yelling at you, so it's like I kind of like having you back.

Oh, and 00 Nina On oni oni down B j.

I'm not sure that's a tough one.

Call it the only way I'm behind that virtual machine for awhile past link where they looked for it.

Not entirely sure which virtual machine you aren't talking about.

Although my guess would be the cto on.

So there's actually a link.

We shortly orbit lead.

It s so if you go to this link, there is a beautiful block post by a tempting the chance of a person named Charlie.

Whoa!

And he wrote, That's kind of like set up, walk through on all subjects, anything on the CT if we're gonna do today, I followed his walk through to set everything up, and then that's when I stopped.

Um, so definitely a good a good thing to go and follow If you want to kind of play around on your own AWS instances, we're doing all this for free, but technically 38 of the U.

S.

So you're welcome to you.

Follow along if you like.

If you wantto get some cool bug bounty money from AWS than you could try and hack into the box for using today we've set up a firewall that hopefully drops all traffic but ours.

So if you find a way through, you know, let us now and then we'll tell you had to buy us and we'll share money against they're going to They're going to damage.

Tell Yeah, Uh uh, Sorrel CS tells us only means demon and Japanese.

This is true.

This is true.

It's good to know.

I don't know the whole lot of Japanese, but take your word for it.

People.

People are talking about CC line.

There's a scratch episode that was so nice.

It's been a while, but I vaguely remember that and then shut up to David in the chat.

David J.

Malin.

Thanks for joining us today, everyone.

Um And then also Yeah.

Shallots again for 50th episode, which I thanks to David for the support on the show, we've been able to get, uh, that far, So appreciate it.

All right, well, let's, uh, top into it, so we will kind of, like breeze through some of the parts that we did last time on.

Then we'll be on a new puzzle that either of us look that true.

Yeah, we're turning in for the first time.

We did do this.

We didn't use this part of the CCF s.

What kind of like a filter it it is set up correctly this time.

Sorry.

Before we kind of like the idea of the show, at least when I'm on, is usually to kind of show everyone what it looks like to go through things from scratch without any prior preparation.

Except for just knowing about it on dso the goal last time was kind of like, Well, just kind of set it up, you know, four minutes before the show starts and it'll work.

But there was a little bit more setup involved than I had realized in, so I messed it up.

And then we kind of dealt with the repercussions of that.

We were about to solve a couple puzzles.

We didn't still solve something which was cool, but this should be a little bit easier for us.

It's a fairly straightforward C t f.

I say that I'll mess up.

I'm positive.

Yeah, I also that big night points out that I had midterms last time, and that is 1% correct.

I was coming out for, like, four midterms and a final project paper presentation will ever know more of those.

Um, I got all the midterms back.

Not great, but like, you know, I am not is exhausted by those were over over and done with at this point.

Exactly.

Maybe that's that's so also wanted to point out that if you ever feel like I'm laughing too much, you're missing the joke.

You're not missing the joke.

I laugh too much.

Uh, come in a YouTube video from, like, four weeks ago or something.

It was like, I don't understand what's happening.

I just like loving everything was holding.

It's like a lady, so don't worry about.