Instructor: Hashcat. 2 2
Hashcat is the last enumeration tool 3 3
we want to talk about. 4 4
Now, the reason we're bringing this up 5 5
is because we just talked about the fact 6 6
that you might want to brute force a password, 7 7
such as a hash that you've collected over the network 8 8
or something like a wireless password. 9 9
And to do that, you're going to use something like hashcat. 10 10
Hashcat is a command line tool 11 11
that's used to perform brute force 12 12
and dictionary attacks against password hashes. 13 13
Now, hashcat could be really slow in the old days. 14 14
The reason for this is you'd have to actually guess 15 15
every single option as you're going through those hashes. 16 16
But smart people had figured out 17 17
there's a quicker way of doing this. 18 18
Instead of relying on the CPU, 19 19
let's rely on the GPU, or graphical processing units. 20 20
Now, GPUs can be relied on by hashcat 21 21
to perform the brute force cracking much quickly. 22 22
Why is that? 23 23
Well, because GPUs are made to do complex math 24 24
in a very quick fashion. 25 25
When you create graphics on a screen, 26 26
it takes a lot of mathematical computations. 27 27
And so these GPUs are extremely fast 28 28
at churning out things for mathematics 29 29
that would create those 3D graphics, 30 30
and that same technology can be used for password cracking. 31 31
For instance, here you can see a rig 32 32
that is one of five servers that somebody put together. 33 33
They put these five servers together 34 34
and each of them had a bunch of GPUs. 35 35
Together, they had 25 GPUs. 36 36
Now, this rig was able to crack 348 billion, 37 37
billion with a B, 38 38
hashes per second. 39 39
Now, luckily, this machine was built 40 40
all the way back in 2012 41 41
and it focused on LANMAN and NTLM hashes, 42 42
both of which only took a few minutes to crack. 43 43
But you can see here just the power of using these GPUs 44 44
over traditional CPUs 45 45
when you're conducting this type of hash cracking. 46 46
Now, our modern hashes like SHA256 47 47
are much more resilient to this type of attack, thankfully. 48 48
But if you have enough GPUs put together, 49 49
you could put together enough power 50 50
to crack those things as well, 51 51
and that's one of the things that we really worry about 52 52
in the security industry. 53 53
If people can get enough power, 54 54
they can start cracking a lot of the passwords 55 55
and security that we use. 56 56
So how do you use hashcat? 57 57
Well, it's pretty easy. 58 58
It's actually a command line program, like I said. 59 59
So you just type in the word hashcat, 60 60
and then -m and give it the hash type, 61 61
for instance MD5, 62 62
then -a and the attack mode. 63 63
Do you want to do brute force or dictionary attack? 64 64
And then -o and you give it the output file. 65 65
Where do you want to save your information to? 66 66
And then you have to give it an input file 67 67
with all those hashes. 68 68
That's it, one simple line of code 69 69
and you can start cracking hashes. 70 70
When you do that, it's going to give you a screen 71 71
that looks like this, and it's going to start running. 72 72
It's going to tell you what kind of hash it's looking at. 73 73
In this case, LTLM version two. 74 74
It's telling you the hash target that it's going after, 75 75
what the time started was, 76 76
what the estimated time of completion is, 77 77
and how many guesses it's going through. 78 78
In this case, we're just trying to crack 79 79
one administrator hash, but how fast can it do it? 80 80
Well, if you look at the speed line, it tells you. 81 81
It's currently doing 364,000 hashes per second. 82 82
Now this is just on somebody's standard laptop. 83 83
This isn't even using a full, dedicated GPU rig 84 84
like I showed you earlier. 85 85
So this just shows you 86 86
how powerful using something like hashcat can be. 87 87
Now, for the exam, do you need to know how to use hashcat? 88 88
No, you don't. 89 89
But you should know that hashcat is used 90 90
for brute force attacks. 91 91
And if you know that much, you'll do fine on the exam.