The DMZ - 2018-10-27

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11:22 AM

@HamZa For starters, get something cheap. You don't need a powerful system to fuzz until you've already heavily optimized your fuzzers. And you can always modify fuzzers to better suite your needs. I know one guy who made his own fuzzer which is far more effective than AFL and utilizes TSX to fuzz individual registers in single functions. That can make you a small fortune.

Honestly, most of the time you can happily fuzz on nothing but your personal laptop, with even tiny optimizations being worth more than buying a new system. Only pay for a really nice rig if you already know it's as optimized as it can get and you really know you need more power. Also, you can use a botnet. :)

11:39 AM

@J.J This just makes me really tempted to try to find it.

Anonymous

12:05 PM

@forest Huh?

Anonymous

Find what?

Anonymous

Oh, you mean my blog lmao.

118

A: How do services with high uptime apply patches without rebooting?

There are various utilities in different operating systems which allow hot-patching of running code. An example of this would be kpatch and livepatch features of Linux which allow patching the running kernel without interrupting its operations. Its capabilities are limited and can only make trivi...

I really don't get how quick and dirty answers of mine like that can get so many upvotes when a post hits HNQ. It's really not that interesting a question.

Nor paired with a particularly detailed or clever answer.

36

Q: A man on a work project in West Africa asks me for 2000 - is this a scam?

A man that I met on Facebook was called to do a job in West Africa. He got there and found out that there is a problem with his Swiss bank account. He needs 2000 to finish the job so he can come home. He gave me the account numbers so I could check and the account says that he has 40,000,000 ! ...

How stupid can people be?

I guess that explains why HNQ always collects the dumbest questions.

I'd think that the intersection between the set of people who are intelligent enough to find the correct Stack Exchange site and post a question that doesn't get closed instantly for being retarded, and the set of people who are dumb enough not to realize instantly that this is a scam would be nil. Humans are confusing.

Anonymous

It's because you're a genius Forest.

Anonymous

Look at my flatline on my profile.

Anonymous

12:14 PM

Doctors need to take my life support away TBH.

I'm not even close to a genius lol

heh

Anonymous

I just have zero motivation to post answers.

Anonymous

Plus, I only answer questions I know that I know the answer to so that I avoid posting shitty answers but I've not seen many questions I can do that with really...

Anonymous

:p

I don't often post either, only once every few days I suppose.

Anonymous

12:23 PM

:p Well, that's okay because you post quality.

Anonymous

I think once I finish my OSCP I will find it a lot easier to answer some of these practical-based questions people ask :p

Anonymous

I want to find time to learn enough about Crypto to participate on CryptoEx but that could take a while..

Oh shit, that reminds me. I had a dream that I was studying for CISSP and was doing the exam but the very end of it was too confusing to me (I couldn't understand the instructions). Then some sort of space aliens came and took over the Earth, but my instructor said that I had to finish the exam anyway and if the aliens took over the room I was in, I would have to submit it unfinished.

It was a very stressful dream.

It's hard to understand vague dream-inspired exam questions logically.

Almost as hard as remembering command line syntax in a dream lol

Anonymous

You dream about that? See, this proves I'm not dedicated enough I still dream about Keira Knightley never anything IT related lmao.

Anonymous

I guess I need to be more passionate :p

12:29 PM

I have very intense and very strange dreams.

Anonymous

Hahah :D

Everything from NSA folk who know the internals of the SAVILLE algorithm throwing flaming axes at me in the snow to trying to figure out how to represent an animation of two people's silhouettes kissing in ASCII so it can be entered as a command line argument. Combined with the occasional violent dream like finding a child terrorist and stabbing them in an old toybox. But I rarely remember them all.

Partially loaded webpages can be so creepy. I just got a page with a teeny tiny search box on the top left with a gigantic magnifying glass search button taking up almost 100% of the browser window.

Anonymous

Has anyone ever told you-you're a weirdo Forest? :O

Anonymous

Hehe, I'm weird too don't worry.

Every once in a while.

1:09 PM

s/people's/peoples'/

That one always gets me.

1:35 PM

Quick question about `etc/shadow`: In this file, passwords are stored are in hashed form(Sha512, by default) , right?
So, If my password is "password" then sha512 of "password" is `B109F3BBBC244EB82441917ED06D618B9008DD09B3BEFD1B5E07394C706A8BB980B1D7785E5976EC049B46DF5F1326AF5A2EA6D103FD07C95385FFAB0CACBC86`

But in `etc/shadow` it has been saved as `$6$vt8hjW0w$nHUwU1KHppmdEzHJfzYDXUrbHiEOjiPi25EDfiJgiQ/04sWtUc/PLGaCiQTSp23xKd89sNl9NWeKy91R8u1K7.:17831:0:99999:7:::`
How?

Oh

I did something related this morning

sha512crypt != sha512

Oh I see

@daya Well firstly, the password is salted, not just hashed. Secondly, it doesn't have to be encoded in hex, it can be encoded in base64 (as you see).

But In a book I read that crypt function "encrypts" passwords using DES which is an encryption algorithm but As we know passwords are *not* encrypted but hashed.
So how this statement follows?

$6$ specifies SHA-512, $vt8hjW0w$ is the salt, and the rest is the hash.

@daya A long time ago, DES was (ab)used like a hash.

It was a very weak scheme back when the original crypt() function was used.

Nowadays, we use a hash, not DES. The only time you'll see DES used as a hash function today is in image boards like 4chan for tripcodes. :P

@daya DES has a 64-bit input and a 64-bit output. That's why the input for old crypt() was limited to 8 1-byte characters (64 bits), because it was directly fed into DES.

Er, scratch that. Actually the password was truncated to 8 characters and was the key, and it used 7-bit ASCII with a 12-bit salt to make up the 56-bit key.

1:46 PM

@forest Sure, but I didn't get it doesn't have to be encoded in hex, it can be encoded in base64 (as you see). you mean during hashing it can be encoded in different number systems? (pardon, I don't know much about crypto)

I mean sha512 of "password" will be the string I mentioned above which is in hex
So how it can be in base64?

@daya A hash outputs raw binary, not hex or anything else. A 128-bit hash outputs 128 raw bits. People often represent hashes in hex, but you can represent it in any encoding, including base64. All that the /etc/shadow file contains is a base64-encoded version of the password. If you use the sha512sum utility, it displays it in hex.

But a hash is not actually either hex or base64, it's raw data.

Also, see man7.org/linux/man-pages/man3/crypt.3.html for more info on crypt().

Oh, that means we can enode that raw data in any number system

Correct. People just use hex because it's easy for people to understand.

2:02 PM

One last question: While using openssl for generating passwords,
for e.g `openssl passwd -salt 74 password` which gives 74Afw8lruFEwg then why salt is first two characters of the string? and why not randomly placed in string? how it is safe?

Why can't it be prepended to the string?

damn, why code formatting is not working in chat

A salt is public (or at least stored with the hash). It's not secret.

Oh lol

I forgot that ;) It is always visible in /etc/shadow

Yep. A salt's goal is to make sure hashes are always different, even for the same password, because "salt1password" and "salt2password" obviously have different hashes, even if "password" and "password" have the same hashes.

2:08 PM

Yeah but if somebody has stupidly manually choosen a same salt then the hashes will be same

Right, that's why the salt should be generated randomly.

Also imo there is no point of manually choosing the salt let the crypt() function decide it randomly

Thanks forest for all info :)

No problem.

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