The DMZ

I was busy with stuff.

Or alternatively: Yes I was dead, but I got better.

Anonymous

:p ahah.

Anonymous

Well, welcome back :p

Anonymous

You'll be pleased to know, I've somewhat fixed my sleep @forest

Anonymous

9:45 AM

It's better... I'm still drinking a lot of Red Bull to stay awake though.

Nice, you'd you do it?

Anonymous

I don't know, it just got better.

Less anxiety now?

Anonymous

But eh, it is still not great. But I don't think that will change until I meet her so.

Anonymous

Oh no I still have that lol.

Anonymous

9:46 AM

I'm still nervous as hell.

ah

I found the most confusing mathematical paper explaining the most simple concept.

kodu.ut.ee/~lipmaa/papers/lip02c/pht.pdf

This explains two equations:
a' = a + b
b' = a + 2b
Both mod 2^n.

Such simple equations, but with such a complicated effect on cipher design that it warranted a paper full of dense mathematics to explain its differential properties.

Anonymous

O.o

I'm still struggling to digest it all.

Anonymous

How does that have a complicated effect on cipher design?

Anonymous

I don't get it...

9:49 AM

s/it all/a useful fraction of it/

@J.J Because of the differential properties.

Anonymous

Wait so.

Anonymous

a' = a + b

Anonymous

Is just mod 2^n.

Anonymous

???

No I mean:

a' = a + b (mod 2^n)
b' = a + 2b (mod 2^n)

Anonymous

9:52 AM

Oh......

Anonymous

Makes more sense now :p

You know how modular arithmetic works right?

Anonymous

On a very shitty level yes :p

Those equations together make up the Pseudo-Hadamard Transform (PHT).

See the box labeled "PHT" in this diagram of a Twofish cipher round? That's it.

Anonymous

Oh.

Anonymous

10:01 AM

I see.

@J.J Modular arithmetic is actually really easy. Think of it like an analog 12-hour clock. What is 2 o'clock plus 3 hours? 5 o'clock. What about 11 o'clock plus 3 hours? Not 14, but 2! (Note that clocks start at 1, rather than 0 as with standard modular math).

Anonymous

Yeah it works on the idea that it is impossible to know how many times someone went round, right?

Anonymous

Or am I just dense as fuck?

Anonymous

At least, that is how Computerphile explained it.

You're exactly right.

At least, that's why they're often used in cryptography.

Anonymous

10:03 AM

:p

Anonymous

I do know some things then.

Anonymous

That surprises me, I feel like I know nothing. I've got a severe case of imposter syndrome.

But the other important fact is that you can squeeze these numbers into a much smaller value, so in the diagram above, each of those lines have a width of 32-bits. Modular arithmetic allows you to add two 32-bit values without risking a value that is "too big to fit" coming up. Hell, you can even multiply them!

Anonymous

Ah, as you're here Forest.

Anonymous

Any book recommendations for learning CPU architecture?

Anonymous

10:04 AM

I want to read the Intel manual but I won't understand it until I get some kind of primer.

Any particular ISA?

Anonymous

(I think)

Anonymous

Hmm, not really.

Anonymous

I just need some primer on how CPUs actually work!

Anonymous

So that I can then read the Intel manual.

Anonymous

10:05 AM

Because I looked at a few pages and I was utterly lost.

The Intel manual is for more advanced implementations, as it gives detailed information pertaining to throughput, latency, port conflicts, out-of-order execution, etc. All these things are super useful if you need to write ultra-optimized assembly code, but it's far more than you need to understand the ISA.

Anonymous

Yeah but it interests me :p

Anonymous

But I feel like I need to learn CPU architecture basics.

Anonymous

Just don't know where to start with that.

I suggest learning MIPS then.

There's this "emulator" out there called MARS, if I remember correctly.

It implements a complete MIPS instruction set, and the emulator even includes a few syscalls so you can learn how a syscall ABI works.

And I suggest MIPS because it's a simple but powerful ISA and is ubiquitous in embedded environments. While x86 or ARM may be more complicated and some things are done differently (e.g. x86 has "flags" which MIPS does not have, and x86 has many complicated but slow instructions, whereas MIPS has fewer simpler but faster instructions), you will still learn a lot about how CPUs work on the machine code level. Once you know one ISA, other ISAs will come far more easily.

Anonymous

10:09 AM

Alright, I'll look at that.

Anonymous

Do you have any book recommendations? I did see one that looks good, let me find it.

If you really want an x86-like instruction set though, try MCS-51.

Anonymous

This one - elsevier.com/books/computer-architecture/hennessy/…

Anonymous

But... Man, $88 for a book!?

I can't think of any good books, mostly because I didn't learn from books, not because they don't exist (I'm sure there are plenty of good ones).

@J.J I assume it's assembly you are curious about, rather than the internals of a CPU?

Anonymous

10:13 AM

Oh no.

Anonymous

The internals of a CPU.

So more more electronic engineering than interacting with a CPU?

Anonymous

I mean, I'm curious about everything, ahaha.

Execution units, port conflicts, out-of-order sequencing, etc?

Anonymous

i want to get into electronics too, yes.

Anonymous

10:14 AM

I don't know where to start with that either.

Anonymous

I've got too many interests :p

That stuff is usually way more advanced. I'd honestly start with assembly, since it teaches you how CPUs work on the outside. From there you can learn how they work on the inside. After all, learning how the fetch-decode-execute sequence works is useless if you don't know how registers work.

Anonymous

Yeah that is why I'm doing the SLAE, Forest :D

Anonymous

For the ASM stuff.

@J.J How much do you know about ICs in general?

Anonymous

10:16 AM

I don't even know what an IC is.

Anonymous

So I guess, nothing?

Integrated circuit.

Anonymous

Oh yeah.

Anonymous

Nothing.

Anonymous

I know nothing about electronics.

10:17 AM

Then I think learning about the internals of a CPU would be difficult. It's like being curious about enzyme kinetics without knowing what a cell membrane is made of.

Though if you really want to press on, Agner Fog's x86 optimization papers are great.

The multi-thousand page Intel developer manuals are also necessary.

They touch on the very basics of internal CPU architecture (for x86 at least).

Oh! Actually, you could learn CHIP-8!

It's a super simple CPU designed for learning.

Anonymous

I will look at that.

Naturally it's not at all representative of a modern, high-speed CPU, but it shows you how they can work on the inside. Modern CPUs are insanely complicated because they need to squeeze out every last picosecond of performance (and yes, deep inside the CPU, picoseconds matter, not just nanoseconds).

Anonymous

Wow.

Anonymous

One day I will learn all this.

Anonymous

Has Jann Horn just been eating intel chips for breakfast or something?

Anonymous

10:22 AM

SInce he was 4*

@J.J One fun thing I learned is that, for a modern x86 core, when it is powered on, each component slowly turns on, and stabilizes over time. Each subunit has a sort of "lock" that is enabled only when it is stable, so powering on a CPU makes it behave almost like a complex chaotic system.

And by powering on I don't mean loading an OS which takes tens of seconds, but bringing the CPU into an electrically-defined state, where the "instant" application of electricity is actually more of a gradual slope upward from 0V to the target voltage.

Anonymous

Oh wow.

Anonymous

Man, I don't understand how some people are so intelligent.

Anonymous

I feel like I could never be this intelligent because I was never academic.

It's the sphere of knowledge.

Or whatever it's called.

The people who know so much about deep, detailed electronic design probably wonder how the hell you know how to do what you consider basic networking configuration!

Anonymous

10:26 AM

I guess so.

The thing is, we're surrounded by so many people who may be experts in one specific thing. The result is that we see "ourselves" as holding this tiny bit of knowledge, and "everyone else" knowing ever so much more.

So yeah collectively, everyone else knows more than you will ever know, but individually, each person, including the people you consider experts, don't necessarily know what you know. I've studied biochemistry and neuroscience, and I'd bet that most of the genius cryptographers whose most basic papers that they could write in their sleep fly way over my head would be totally lost if I were to talk to them about what I consider basic or model biochemical pathways.

The end-result is that each person feels like they know so little and that everyone else knows so much. But each person feels that way. There are very, very few polymaths who are truly experts in a huge variety of subjects.

No one is a domain expert in everything. :P

10:43 AM

@J.J Anyway to rehash the CPU stuff above, learn MIPS for RISC, MCS-51 for CISC, CHIP-8 for internal CPU design, and Agner Fog / Intel developer manuals for detailed x86 internals and optimizations. That sums up my recommendations.

Anonymous

Alrighty @forest thank you.

Anonymous

As for the knowing so little.

Anonymous

I just feel like an imposter.

Anonymous

ALWAYS.

Anonymous

Even in networking where I have ACTUAL qualifications.

Anonymous

10:44 AM

I still feel like an imposter :/

Lots of people do. It's only when you start to know a lot that you learn how much you don't know. The smarter someone is, the more acutely they are aware of how little they actually know. It's the dumb people who see the world as so limited that the ratio of knowledge they know exists to the knowledge they have is small.

There will never be a time when you think you know it all. For every concept you begin to really understand, you'll discover two new concepts that go over your head.

@J.J Think about it this way: The average person thinks that "networking" involves nothing more than configuring a router or learning what "subnet" and "DNS" mean. Those average people think that they know maybe 10% of how networking works, with the remaining 90% being stuff in their router manuals that they haven't read yet. You, being someone who actually knows networking, sees the sheer number of complex protocols and convoluted routing techniques that exist.

So because you know so much more than the average person, you can say you know only 0.1% of it, while the average person who knows nothing thinks they know 10%!

Anonymous

I guess so..

It's all psychology. How much of meteorology do you know you don't know? For me, I struggle to remember the names and shapes of various kinds of clouds, much less remember their properties. A meteorologist on the other hand knows a thousand things, and is aware of a million things he doesn't know!

Anonymous

Yeah that is true.

Anonymous

I don't know much about much though lol.

Anonymous

10:54 AM

And I have the memory of a sieve.

No one does. Polymaths are rare as hell.

Anonymous

Like uh I can remember technical things

Anonymous

But like..

Anonymous

Remembering what bin something goes into?

Anonymous

Basic things like that I am so forgetful with it is weird.

10:55 AM

The human brain is able to learn things so quickly not because of its ability to remember, but its ability to forget. The act of filtering out information is vital.

It's also why machine learning is so difficult. Machines are amazing at remembering things. They can perfectly memorize terabytes of high-samplerate data, but they are almost completely incapable of forgetting the irrelevant noise.

We should feel lucky that we can forget things. I for one am glad the only things that I remember are things I try to remember. I would hate having to recall the exact number of wrinkles on my bed sheet when all I wanted to remember is to do my laundry!

Anonymous

Hahha :p

Anonymous

Most of this is just caused by my anxiety to be honest.

Anonymous

I worry about stupid things like, what am I going to eat? Or in 30 minutes will I have learnt anything?

Anonymous

And then worrying about the future a lot does not help ;p

A gnat doesn't worry. It just lives day to day. That doesn't mean it has a better life.

Worrying about the future is the curse of humanity.

(Or at least the curse of being a higher primate)

Anonymous

11:00 AM

I hate worrying.

Anonymous

I mean I literally worry about everything & anything (well I said before so)

Anonymous

It is awful, it's really awful.

Anonymous

But oh well, I'm not dead so.

The solution is to optimize your worrying so you can worry about only what matters. Obviously it's easier said than done, so I'm not trying to say "just do this".

Anonymous

A lot of my worry will disappear in 28 days which is great.

AviD

11:01 AM

Hey all, FYI:
OWASP's Global AppSec Tel Aviv (the conference formerly known as AppSecEU) will be held the last week of May - 26-28 are training days, 29-30 the conference! https://telaviv.appsecglobal.org/

Our Calls for Presentations and Trainings are open now!
CFP: https://owasp.submittable.com/submit/132865/global-appsec-tel-aviv-2019-call-for-papers
CFT: https://owasp.submittable.com/submit/131191/global-appsec-tel-aviv-2019-call-for-trainers

Anonymous

I cannot wait for that (obviously) but I'm sure my brain will find something new to get worried about constantly lol.

That's when you meet with your girlfriend?

AviD

I hope to see a lot of Sec.SE / DMZ folk there :-)

Anonymous

@forest Yup!

Anonymous

28 days she comes here.

Anonymous

11:04 AM

We're renting an apartment for two weeks.

Anonymous

(Which is really, really not cheap by the way. Luckily we're paying half each)

Anonymous

But actually, it is still probably cheaper than a hotel and will be a better experience anyways.

I have an RV for that kind of thing. :P

They're actually not that bad.

Anonymous

Hahah, well, I don't own an RV and we're staying in London :p

Anonymous

I gotta' go get her from the airport then we're just staying in London for two weeks.

Anonymous

11:09 AM

Away from my family, away from everyone who knows me.

The 10,000 Domino Computer

11:28 AM

►

3

I wonder if there are any robotics designs that can build domino chains according to digital schematics... That would make setting world records a simple matter of buying enough dominos. It would also greatly speed up assembly, and safely at that.

Anonymous

I literally do not understand the point of domino's.

Anonymous

Okay, I understand people have different interests and hobbies but really, what do you get out of that?

Anonymous

You're just building something that takes ages to push it over...

The original point of dominos or like, domino circuits and the like?

Anonymous

If you get off on destruction why not just buy an old car and smash it to bits?

11:37 AM

It's just aesthetically pleasing to see them fall over.

Anonymous

Yes it is.

Anonymous

But think about how long it took them to put that together.

Anonymous

Only to push it over....?

Tell that to a chef.

Anonymous

I don't understand it and I don't think I ever will, but oh well. lol.

11:38 AM

All that time and effort put into making beautiful food, only for someone to eat it!

Anonymous

Yes but with a chef he is actually achieving something.

Anonymous

Someone is actually eating, they're getting something.

Anonymous

What are you getting by watching a domino fall?

Anonymous

Like is it the destruction?

Aesthetics is still something.

Anonymous

11:38 AM

I guess.

It's not the destruction at all.

Anonymous

I just don't understand why you'd waste time like that but each to their own.

If it were, no kid would ever be pissed off at wasting hours just to accidentally knock one domino over. It's the end result that matters.

Anonymous

Yeah, you're right.

Anonymous

I just don't understand it, lol.

Anonymous

11:39 AM

But then, people don't understand how I get enjoyment out of listening to the most depressing music.

Check YouTube for some impressive world records and you might change your mind!

Anonymous

So as I said - each to their own.

Also, it's computation. :P

Anonymous

:p

Have you ever played with model rockets as a kid?

Anonymous

11:41 AM

Nope.

Anonymous

I played the computer as a kid.

Ah. It's similar in that you "destroy" small rocket fuel packs.

Anonymous

Computers have always been my entire life.

But the joy is in watching it fly, even though you'll have to throw away the spent fuel when it's done.

Anonymous

Since I was like two years old.

Anonymous

11:42 AM

The first game I played was Tony Hawk on the PS1.

Ah, that makes sense. For computers, nothing is disposable.

Everything that works once should work again.

Anonymous

Yup. Computers have literally been my life since very, very young.

So you never have a situation where using something also destroys it.

Anonymous

Well, I say "computers". Consoles were my life since very young & then I got a computer at 6.

Anonymous

And then at 9-10 I built my own computer.

Anonymous

11:43 AM

Either way, always something with computer parts :D

I didn't get a computer until I was like... 15. Until then I had to use a family one. Though I did have a GameBoy and GameBoy Advance, if that counts.

Anonymous

Wow.

Anonymous

I cannot imagine that, the computer is all I've ever known.

Never console games though, always handhelds.

Anonymous

I did have a GameBoy too!

Anonymous

11:43 AM

I think it was the colour or something? It was a cube in like dark blue.

I'd have though the DS would be the thing when you were younger.

Anonymous

My grandfather bought it for me when I was like 5 or something I think.

It's the one that looks kind of like a fat remote control.

Anonymous

Ah.

With the longer cartridges.

Anonymous

11:44 AM

This is the one I had.

Anonymous

This one.

Ah, that's a Gameboy Advance SP.

I had one of those as well. Two actually.

At least, when they came out. I started with earlier ones.

Anonymous

Yeah, I loved that thing!

Anonymous

11:46 AM

Splinter Cell was my favourite game.

But yeah the GBC is much older than the GBA SP.

Anonymous

I never completed it though :(

Anonymous

I also had like this Power Rangers game.

Anonymous

@forest Question for you: do you know how secure/insecure the SanDisk USB encryption tool is?

Is that some software utility that encrypts USB drives?

Anonymous

11:48 AM

Yup.

Anonymous

It comes pre-installed on all their USBs.

Anonymous

But it does not actually encrypt the USB.

Then it's crap. Don't use it.

Anonymous

It makes a folder called "vault"

Use VeraCrypt if you want to encrypt a USB drive.

Anonymous

11:49 AM

Could I encrypt over the top of the SanDisk vault...?

I suppose.

Not sure why you'd want to though.

Anonymous

Well, 'cus I already used this vault thing.

Anonymous

It's basically an application, you tell it what to encrypt on the drive, it does it, makes a new folder called "vault" and places all the files in there.

Anonymous

And then it makes like "0a", "0b" and so on.

Yeah then it'd be fine. I'd still suggest using only VeraCrypt though, only because it's better supported. If you ever lose the decryption program, you might not be able to decrypt it again. And, of course, it might not be able to handle corruption or subtle bugs as well as VeraCrypt.

Anonymous

11:51 AM

Hmm, oka.

Anonymous

12:08 PM

@forest Do you know much about Corelans exploit dev courses?

Anonymous

I don't suppose you do...?

Nothing at all.

Anonymous

Hmm, they are so pricey.

Anonymous

$3500 for the Exploit Dev Introduction course.

That's not an unusual price.

I've taken 3-day classes that were more expensive. :P

Anonymous

12:12 PM

Yeah I can imagine. The advanced course doesn't even have a price listed!

daya

12:31 PM

I am doing http://leettime.net/sqlninja.com/tasks/deathrow_ch1.php?id=1 (It is under Basic Injection > Death Row Injection)
And when I append `'`
It triggers `Error While Selection process : You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' and id=1' limit 1' at line 1`
But not sure I understand how _exactly_ the underlying query is executing?
I mean is it like `select username from users where id=1 limit 1`
Or something like `select username from users where id="1 limit 1"`

Oh god, why code formatting is not working

very annoyed

Enough of manual testing..

I think I should move to automated tools like sqlmap :P

Please don't confuse ' '(single quote) with ` `(backticks)

I mean I used backticks to format code but It didn't worked for some unknown reason

1:12 PM

wow: troyhunt.com/the-773-million-record-collection-1-data-reach

first time I'm in a password dump

HamZa

1:39 PM

vergiliusproject.com

@J.J correlan has his own slack btw

Anonymous

4:05 PM

@HamZa Does he?

Anonymous

I thought Corelan was a group though?

HamZa

7:40 PM

well now i'm not sure haha
anyways, sometimes they share an invite link which is only valid for a week or so

Rory Alsop

8:19 PM

@J.J that is good too, but domino rallies are much cheaper

8:36 PM

I'm inclined to change the title of this question to something like: "Is it safe to give my email address to a service like haveibeenpwned in light of the recent publication of "Collection #1"?" because the old one is kinda bad - but I'd like to get an "okay" from other members, because that seems like a more severe edit

AndrolGenhald

@TomK. Sounds like an improvement to me

maybe a bit long though

9:01 PM

hm @Anders just edited it

maybe he has an opinion

10:41 PM

is there a CVE yet for the fact that the permission system in the "new" type of FireFox extensions is basically useless?

I think the problem applies to Chrome as well

@NH. Huh?

everyone requests the broadest permission

"see data for all websites' or something like that.

terribly designed permission

nvd.nist.gov/vuln/detail/CVE-2018-12369

"WebExtensions bundled with embedded experiments were not correctly checked for proper authorization. This allowed a malicious WebExtension to gain full browser permissions. This vulnerability affects Firefox ESR < 60.1 and Firefox < 61."

not sure if that is what you meant though

no, I mean the design is bad

that vuln is not working as designed, I'm saying the permissions need redesigning.

ah okay

no idea about that

not sure if that would qualify as a vulnerability though <:

I guess you'd have to a short explanation