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- You're going to encounter many acronyms

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when looking at wireless networking,

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particularly WiFi networks.

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So we have WEP, WPA,
WPA2, there's WPA3 now.

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We got encryption methods down here,

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we got authentication
protocols down at the bottom.

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We're gonna take a look at a lot of these

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over the coming slides.

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Starting off with WEP,

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WEP was the original.

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Completely insecure method of
securing wireless networks.

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It was in that original standard in 1997,

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it uses Rivest Cipher
4 as the stream cipher.

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There is a 50% chance

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that an initialization vector

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will be repeated in 4K
frames, 4,096 frames.

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If you're able to capture
that initialization vector,

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it gives you a path to
crack the pre-shared key

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that both sides of the
communication need to be aware of

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in order to establish
that encrypted channel.

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So we had WEP-40 and WEP-128.

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WEP-128 was the more commonly
used method of encryption.

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It had a 24-bit initialization
vector and a 104-bit key,

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and the combination of these

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you would have to go and type in

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a bunch of ASCII characters.

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It was all the hex representation
of that pre-shared key.

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This final bullet point right here.

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If you don't have enough traffic

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flowing across the wireless network,

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you can inject frames

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in order to cause the IV to be repeated.

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After WEP was cracked quite easily,

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and as computers started to
become faster and faster,

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it was possible to crack WEP in seconds.

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It was very easy to do.

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So they needed a solution to that.

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And as they were working on WPA2,

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they put out a stop gap of WPA in 2003.

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So we had 1997 to 2003.

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We had six years for us to
figure out that W-E-P or WEP,

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would not work for us.

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So we put out a stop gap.

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And all they essentially did

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was they changed the encryption protocol,

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and they upped the size of
the initialization vector

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and the key.

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So we got 48-bit IV, 128-bit key,

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compare that to WEP-128, 24 and 104.

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So WPA2 was finally released.

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That became the standard
for wireless encryption,

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or encryption and authentication
on wireless networks,

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that is defined in IEEE standard 802.11i.

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128-bit key length.

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We're now using advanced
encryption standard, or AES.

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As well, we are using counter mode

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Cipher Blockchain MAC
Protocol for key exchange.

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And if you want to be WiFi certified,

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meaning that you wanna put

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the WiFi trademark on your product,

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then you do to support WPA2 as of 2006.

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In 2018, WPA3 was released.

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We increased the key length.

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We're still using CCMP.

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And if you want to get that
wiFi trademark as of 2018,

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you need to support WPA3.

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But what is WPA?

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Stands for WiFi Protected Access.

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There's two different
methods of authentication

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to actually join these networks.

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We have personal, and we have enterprise.

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With WPA2, we have pre-shared
keys, also called WPA-PSK.

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Don't consider it user authentication.

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It's a password to join the network,

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often called a passphrase,
to join the network.

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Provided it matches on both sides,

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you can join the network and talk,

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and you will exchange keys
with the wireless network

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and be able to communicate.

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With WPA3,

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it's now called Simultaneous
Authentication of Equals.

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It's defined at 802.11-2016.

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This particular key exchange mechanism,

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I believe it's referred to as SAM

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Though the E, and the M,

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off the top of my head,

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I don't know the difference there.

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For enterprise authentication,

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you do have user authentication.

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So user and password to join the network.

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This authentication needs to
be authenticated by something.

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So username and password
needs to be sent to something.

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You can still join the network,

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but you will be immediately prompted

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for username and password
in order to continue.

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That brokerage of the
authentication credentials

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is defined in various standards.

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So, 802.1X for wired and
wireless authentication.

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You can see it is pretty complicated.

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The client would join.

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The access point would say,

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"Hey, you need to authenticate to this.

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This is an enterprise network."

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So you need to provide
a username and password.

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The access point would then
broker that communication

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back to a radius server
for approval or denial

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of your request to join.

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The authentication protocol that's used

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as an upper layer Protocol.

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You can see there are several
options available to you.

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From Lightweight EAP.

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EAP is Extensible Authentication Protocol.

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Lightweight EAP, EAP-FAST.

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There are even methods of authentication

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that use certificates.

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Both client side search,

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as well as mutual authentication
using certificates.

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A comparison of the
various encryption methods

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in WEP, WPA, WPA2 and Three.

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For WEP and WPA,

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we are using Rivest
Cipher 4 for both of them.

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Remember that WPA is
that stop gap protocol

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that came after WEP,

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before they finally certified WPA2.

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With WPA2 and Three,

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we switched to advanced
encryption standard,

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the difference being
the length of the keys.

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So we have 128-bit keys with WPA2,

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192-bit keys for WPA3.

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Now you'll notice in the upper left there

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we have good is green, and bad is red.

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And you'll notice we do have
some blue on the screen,

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all of this stuff down here.

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And that is blue,

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because it is an option, it's available.

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Turn it on, good, turn it off, bad.

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So what is wrong with WEP?

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Starting off with,
everyone uses the same key.

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So this is a problem with
any pre-shared key mechanism.

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It's the age old debate of
symmetric key cryptography

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versus asymmetric key cryptography.

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You have public private
keys on the asymmetric side,

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and then shared keys
on the symmetric side.

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For WEP as well as WPA-PSK,
we have shared keys.

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What if someone leaves the company?

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How do you get that key back from them,

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and say, "Hey, don't use
this key ever again,"

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what if they are slightly offended

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that you have let them go?

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You have a key rotation problem

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with pre-shared key deployments,

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and that's where enterprise
authentication comes into play.

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But we'll talk about that later.

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Some further insecurities with WEP,

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the initialization vector size is 24 bits.

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So we have two to the 24th possibilities

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for a single WEP key.

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To the 24th, that's 16,777,000 something.

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And the possibility of seeing an overlap

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of these initialization
vectors becomes a problem.

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Because once you have that collision,

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you see the same IV twice,
then it's possible to crack.

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Now you can inject frames

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in order to cause the the
initialization vector collision

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to occur faster.

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And we'll talk about that.

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So how do we break WEP?

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We are gonna still
continue to talk about WEP,

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because these networks are still in use.

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There's old equipment
running in factories,

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who knows what you might encounter?

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How would you crack WEP?

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We're gonna be using the suite
of tools available in Linux,

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and in subsequent lessons,

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we're actually gonna
walk through the process

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of breaking WEP, screenshots,

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as well as breaking WPA2.

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Starting off we're gonna use airmon-ng

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to put the wireless
interface into monitor mode,

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capture some frames with airodump,

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inject some packets all while capturing,

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and then crack the initialization,

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provided we captured it properly.

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For cracking WPA, you need
this Pairwise Master Key.

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This is shared between both the client

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as well as the access point.

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It's derived from that pre-shared key

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that you type in to join the network.

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The handshake to join the network

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includes this Message Integrity Check.

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The MIC can then be brute forced.

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Similar process, airmon, dump,
replay, crack, in order to...

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So you can forcefully
deauthenticate clients

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so that they would need to rejoin,

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and then we can capture this
Message Integrity Check.

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So how do we protect ourselves

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from these encryption attacks?

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Don't use WEP, of course,

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use WPA3 or Two, Complex Passphrases.

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They don't have to be eight characters,

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which is the minimum for WPA.

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Make 'em long, make 'em complicated.

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Special characters, upper,
lowercase, all that stuff.

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Only use AES for
encryption, don't use TKIP,

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that is considered vulnerable,

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and consider using
higher layer encryption.

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So your Transport Layer Security, IPSec,

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running on top of the
encryption provided by wiFi.