Tutorial Crack Wpa

These are the four handshake WPA packets. These are the four critical packets required by aircrack-ng to crack WPA using a dictionary. Notice that the AP.

Your Wi-Fi network is your conveniently wireless gateway to the internet, and since you re not keen on sharing your connection with any old hooligan who happens to be walking past your home, you secure your network with a password, right. Knowing, as you might, how easy it is to crack a WEP password, you probably secure your network using the more bulletproof WPA security protocol.

You already know that if you want to lock down your Wi-Fi network, you should opt for WPA

Read more Read more

Here s the bad news: A new, free, open-source tool called Reaver exploits a security hole in wireless routers and can crack most routers current passwords with relative ease. Here s how to crack a WPA or WPA2 password, step by step, with Reaver and how to protect your network against Reaver attacks.

In the first section of this post, I ll walk through the steps required to crack a WPA password using Reaver. You can follow along with either the video or the text below. After that, I ll explain how Reaver works, and what you can do to protect your network against Reaver attacks.

First, a quick note: As we remind often remind readers when we discuss topics that appear potentially malicious: Knowledge is power, but power doesn t mean you should be a jerk, or do anything illegal. Knowing how to pick a lock doesn t make you a thief. Consider this post educational, or a proof-of-concept intellectual exercise. The more you know, the better you can protect yourself.

What You ll Need

You don t have to be a networking wizard to use Reaver, the command-line tool that does the heavy lifting, and if you ve got a blank DVD, a computer with compatible Wi-Fi, and a few hours on your hands, you ve got basically all you ll need. There are a number of ways you could set up Reaver, but here are the specific requirements for this guide:

The BackTrack 5 Live DVD. BackTrack is a bootable Linux distribution that s filled to the brim with network testing tools, and while it s not strictly required to use Reaver, it s the easiest approach for most users. Download the Live DVD from BackTrack s download page and burn it to a DVD. You can alternately download a virtual machine image if you re using VMware, but if you don t know what VMware is, just stick with the Live DVD. As of this writing, that means you should select BackTrack 5 R3 from the Release drop-down, select Gnome, 32- or 64-bit depending on your CPU if you don t know which you have, 32 is a safe bet, ISO for image, and then download the ISO.A computer with Wi-Fi and a DVD drive. BackTrack will work with the wireless card on most laptops, so chances are your laptop will work fine. However, BackTrack doesn t have a full compatibility list, so no guarantees. You ll also need a DVD drive, since that s how you ll boot into BackTrack. I used a six-year-old MacBook Pro.A nearby WPA-secured Wi-Fi network. Technically, it will need to be a network using WPA security with the WPS feature enabled. I ll explain in more detail in the How Reaver Works section how WPS creates the security hole that makes WPA cracking possible.A little patience. This is a 4-step process, and while it s not terribly difficult to crack a WPA password with Reaver, it s a brute-force attack, which means your computer will be testing a number of different combinations of cracks on your router before it finds the right one. When I tested it, Reaver took roughly 2.5 hours to successfully crack my password. The Reaver home page suggests it can take anywhere from 4-10 hours. Your mileage may vary.

Let s Get Crackin

At this point you should have BackTrack burned to a DVD, and you should have your laptop handy.

Step 1: Boot into BackTrack

To boot into BackTrack, just put the DVD in your drive and boot your machine from the disc. Google around if you don t know anything about live CDs/DVDs and need help with this part. During the boot process, BackTrack will prompt you to to choose the boot mode. Select BackTrack Text - Default Boot Text Mode and press Enter.

Eventually BackTrack will boot to a command line prompt. When you ve reached the prompt, type startx and press Enter. BackTrack will boot into its graphical interface.

Step 2: Install Reaver

Update: This step is no longer necessary, as Reaver comes pre-installed on Backtrack 5 R3. Skip down to Step 3.

Reaver has been added to the bleeding edge version of BackTrack, but it s not yet incorporated with the live DVD, so as of this writing, you need to install Reaver before proceeding. Eventually, Reaver will simply be incorporated with BackTrack by default. To install Reaver, you ll first need to connect to a Wi-Fi network that you have the password to.

Click Applications Internet Wicd Network ManagerSelect your network and click Connect, enter your password if necessary, click OK, and then click Connect a second time.

Now that you re online, let s install Reaver. Click the Terminal button in the menu bar or click Applications Accessories Terminal. At the prompt, type:

apt-get update

And then, after the update completes:

apt-get install reaver

If all went well, Reaver should now be installed. It may seem a little lame that you need to connect to a network to do this, but it will remain installed until you reboot your computer. At this point, go ahead and disconnect from the network by opening Wicd Network Manager again and clicking Disconnect. You may not strictly need to do this. I did just because it felt like I was somehow cheating if I were already connected to a network.

Step 3: Gather Your Device Information, Prep Your Crackin

In order to use Reaver, you need to get your wireless card s interface name, the BSSID of the router you re attempting to crack the BSSID is a unique series of letters and numbers that identifies a router, and you need to make sure your wireless card is in monitor mode. So let s do all that.

Find your wireless card: Inside Terminal, type:

iwconfig

Press Enter. You should see a wireless device in the subsequent list. Most likely, it ll be named wlan0, but if you have more than one wireless card, or a more unusual networking setup, it may be named something different.

Put your wireless card into monitor mode: Assuming your wireless card s interface name is wlan0, execute the following command to put your wireless card into monitor mode:

airmon-ng start wlan0

This command will output the name of monitor mode interface, which you ll also want to make note of. Most likely, it ll be mon0, like in the screenshot below. Make note of that.

Find the BSSID of the router you want to crack: Lastly, you need to get the unique identifier of the router you re attempting to crack so that you can point Reaver in the right direction. To do this, execute the following command:

airodump-ng wlan0

Note: If airodump-ng wlan0 doesn t work for you, you may want to try the monitor interface instead e.g., airodump-ng mon0.

You ll see a list of the wireless networks in range it ll look something like the screenshot below:

When you see the network you want, press Ctrl C to stop the list from refreshing, then copy that network s BSSID it s the series of letters, numbers, and colons on the far left. The network should have WPA or WPA2 listed under the ENC column. If it s WEP, use our previous guide to cracking WEP passwords.

Now, with the BSSID and monitor interface name in hand, you ve got everything you need to start up Reaver.

Step 4: Crack a Network s WPA Password with Reaver

Now execute the following command in the Terminal, replacing bssid and moninterface with the BSSID and monitor interface and you copied down above:

reaver -i moninterface -b bssid -vv

For example, if your monitor interface was mon0 like mine, and your BSSID was 8D:AE:9D:65:1F:B2 a BSSID I just made up, your command would look like:

reaver -i mon0 -b 8D:AE:9D:65:1F:B2 -vv

Press Enter, sit back, and let Reaver work its disturbing magic. Reaver will now try a series of PINs on the router in a brute force attack, one after another. This will take a while. In my successful test, Reaver took 2 hours and 30 minutes to crack the network and deliver me with the correct password. As mentioned above, the Reaver documentation says it can take between 4 and 10 hours, so it could take more or less time than I experienced, depending. When Reaver s cracking has completed, it ll look like this:

A few important factors to consider: Reaver worked exactly as advertised in my test, but it won t necessarily work on all routers see more below. Also, the router you re cracking needs to have a relatively strong signal, so if you re hardly in range of a router, you ll likely experience problems, and Reaver may not work. Throughout the process, Reaver would sometimes experience a timeout, sometimes get locked in a loop trying the same PIN repeatedly, and so on. I just let it keep on running, and kept it close to the router, and eventually it worked its way through.

Also of note, you can also pause your progress at any time by pressing Ctrl C while Reaver is running. This will quit the process, but Reaver will save any progress so that next time you run the command, you can pick up where you left off-as long as you don t shut down your computer which, if you re running off a live DVD, will reset everything.

How Reaver Works

Now that you ve seen how to use Reaver, let s take a quick overview of how Reaver works. The tool takes advantage of a vulnerability in something called Wi-Fi Protected Setup, or WPS. It s a feature that exists on many routers, intended to provide an easy setup process, and it s tied to a PIN that s hard-coded into the device. Reaver exploits a flaw in these PINs; the result is that, with enough time, it can reveal your WPA or WPA2 password.

Read more details about the vulnerability at Sean Gallagher s excellent post on Ars Technica.

How to Protect Yourself Against Reaver Attacks

Since the vulnerability lies in the implementation of WPS, your network should be safe if you can simply turn off WPS or, even better, if your router doesn t support it in the first place. Unfortunately, as Gallagher points out as Ars, even with WPS manually turned off through his router s settings, Reaver was still able to crack his password.

In a phone conversation, Craig Heffner said that the inability to shut this vulnerability down is widespread. He and others have found it to occur with every Linksys and Cisco Valet wireless access point they ve tested. On all of the Linksys routers, you cannot manually disable WPS, he said. While the Web interface has a radio button that allegedly turns off WPS configuration, it s still on and still vulnerable.

So that s kind of a bummer. You may still want to try disabling WPS on your router if you can, and test it against Reaver to see if it helps.

You could also set up MAC address filtering on your router which only allows specifically whitelisted devices to connect to your network, but a sufficiently savvy hacker could detect the MAC address of a whitelisted device and use MAC address spoofing to imitate that computer.

Double bummer. So what will work.

I have the open-source router firmware DD-WRT installed on my router and I was unable to use Reaver to crack its password. As it turns out, DD-WRT does not support WPS, so there s yet another reason to love the free router-booster. If that s got you interested in DD-WRT, check their supported devices list to see if your router s supported. It s a good security upgrade, and DD-WRT can also do cool things like monitor your internet usage, set up a network hard drive, act as a whole-house ad blocker, boost the range of your Wi-Fi network, and more. It essentially turns your 60 router into a 600 router.

Internet data caps are becoming a reality and can seriously suck. If you re stuck with the

Further Reading

Thanks to this post on Mauris Tech Blog for a very straightforward starting point for using Reaver. If you re interested in reading more, see:

Reddit user jagermo who I also spoke with briefly while researching Reaver has created a public spreadsheat intended to build a list of vulnerable devices so you can check to see if your router is susceptible to a Reaver crack.

Have any experience of your own using Reaver. Other comments or concerns. Let s hear it in the comments.

cracking_wpa [Aircrack-ng]

• Sep 22, 2014  This feature is not available right now. Please try again later. Published on Sep 22, 2014. Category. People Blogs; License. Standard YouTube License.
• This tutorial walks you through cracking WPA/WPA2 networks which use pre-shared keys. I recommend you do some background reading to better understand what WPA.

Previously, we showed you how to secure your wireless with industrial strength RADIUS authentication via WPA-Enterprise. It turns out that there s a little back-story.

How to Crack a Wi-Fi Network s WEP Password with BackTrack How to Crack a Wi-Fi Network s WEP Password with BackTrack How to Crack a Wi-Fi Network.

Cracking_wpa

Version: 1.20 March 07, 2010

By: darkAudax

Introduction

This tutorial walks you through cracking WPA/WPA2 networks which use pre-shared keys. I recommend you do some background reading to better understand what WPA/WPA2 is. The Wiki links page has a WPA/WPA2 section. The best document describing WPA is Wi-Fi Security - WEP, WPA and WPA2. This is the link to download the PDF directly. The WPA Packet Capture Explained tutorial is a companion to this tutorial.

WPA/WPA2 supports many types of authentication beyond pre-shared keys. aircrack-ng can ONLY crack pre-shared keys. So make sure airodump-ng shows the network as having the authentication type of PSK, otherwise, don t bother trying to crack it.

There is another important difference between cracking WPA/WPA2 and WEP. This is the approach used to crack the WPA/WPA2 pre-shared key. Unlike WEP, where statistical methods can be used to speed up the cracking process, only plain brute force techniques can be used against WPA/WPA2. That is, because the key is not static, so collecting IVs like when cracking WEP encryption, does not speed up the attack. The only thing that does give the information to start an attack is the handshake between client and AP. Handshaking is done when the client connects to the network.

Although not absolutely true, for the purposes of this tutorial, consider it true. Since the pre-shared key can be from 8 to 63 characters in length, it effectively becomes impossible to crack the pre-shared key.

The only time you can crack the pre-shared key is if it is a dictionary word or relatively short in length. Conversely, if you want to have an unbreakable wireless network at home, use WPA/WPA2 and a 63 character password composed of random characters including special symbols.

The impact of having to use a brute force approach is substantial. Because it is very compute intensive, a computer can only test 50 to 300 possible keys per second depending on the computer CPU. It can take hours, if not days, to crunch through a large dictionary. If you are thinking about generating your own password list to cover all the permutations and combinations of characters and special symbols, check out this brute force time calculator first. You will be very surprised at how much time is required.

IMPORTANT This means that the passphrase must be contained in the dictionary you are using to break WPA/WPA2. If it is not in the dictionary then aircrack-ng will be unable to determine the key.

There is no difference between cracking WPA or WPA2 networks. The authentication methodology is basically the same between them. So the techniques you use are identical.

It is recommended that you experiment with your home wireless access point to get familiar with these ideas and techniques. If you do not own a particular access point, please remember to get permission from the owner prior to playing with it.

I would like to acknowledge and thank the Aircrack-ng team for producing such a great robust tool.

Please send me any constructive feedback, positive or negative. Additional troubleshooting ideas and tips are especially welcome.

Assumptions

First, this solution assumes:

You are using v0.9.1 or above of aircrack-ng. If you use a different version then some of the command options may have to be changed.

Ensure all of the above assumptions are true, otherwise the advice that follows will not work. In the examples below, you will need to change ath0 to the interface name which is specific to your wireless card.

Equipment used

In this tutorial, here is what was used:

MAC address of PC running aircrack-ng suite: 00:0F:B:AC:82

MAC address of the wireless client using WPA2: 00:0F:B5:FD:FB:C2

BSSID MAC address of access point : :6C:7E:

ESSID Wireless network name : teddy

Access point channel: 9

Wireless interface: ath0

You should gather the equivalent information for the network you will be working on. Then just change the values in the examples below to the specific network.

Solution

Solution Overview

The objective is to capture the WPA/WPA2 authentication handshake and then use aircrack-ng to crack the pre-shared key.

This can be done either actively or passively. Actively means you will accelerate the process by deauthenticating an existing wireless client. Passively means you simply wait for a wireless client to authenticate to the WPA/WPA2 network. The advantage of passive is that you don t actually need injection capability and thus the Windows version of aircrack-ng can be used.

Here are the basic steps we will be going through:

Start the wireless interface in monitor mode on the specific AP channel

Start airodump-ng on AP channel with filter for bssid to collect authentication handshake

Use aireplay-ng to deauthenticate the wireless client

Run aircrack-ng to crack the pre-shared key using the authentication handshake

Step 1 - Start the wireless interface in monitor mode

The purpose of this step is to put your card into what is called monitor mode. Monitor mode is the mode whereby your card can listen to every packet in the air. Normally your card will only hear packets addressed to you. By hearing every packet, we can later capture the WPA/WPA2 4-way handshake. As well, it will allow us to optionally deauthenticate a wireless client in a later step.

The exact procedure for enabling monitor mode varies depending on the driver you are using. To determine the driver and the correct procedure to follow, run the following command:

airmon-ng

On a machine with a Ralink, an Atheros and a Broadcom wireless card installed, the system responds:

Interface Chipset Driver

rausb0 Ralink RT73 rt73

wlan0 Broadcom b43 - phy0

wifi0 Atheros madwifi-ng

ath0 Atheros madwifi-ng VAP parent: wifi0

The presence of a phy0 tag at the end of the driver name is an indicator for mac80211, so the Broadcom card is using a mac80211 driver. Note that mac80211 is supported only since aircrack-ng v1.0-rc1, and it won t work with v0.9.1.

Both entries of the Atheros card show madwifi-ng as the driver - follow the madwifi-ng-specific steps to set up the Atheros card.

Finally, the Ralink shows neither of these indicators, so it is using an ieee80211 driver - see the generic instructions for setting it up.

Step 1a - Setting up madwifi-ng

First stop ath0 by entering:

airmon-ng stop ath0

The system responds:

ath0 Atheros madwifi-ng VAP parent: wifi0 VAP destroyed

Enter iwconfig to ensure there are no other athX interfaces. It should look similar to this:

lo no wireless extensions.

eth0 no wireless extensions.

wifi0 no wireless extensions.

If there are any remaining athX interfaces, then stop each one. When you are finished, run iwconfig to ensure there are none left.

Now, enter the following command to start the wireless card on channel 9 in monitor mode:

airmon-ng start wifi0 9

Note: In this command we use wifi0 instead of our wireless interface of ath0. This is because the madwifi-ng drivers are being used.

The system will respond:

ath0 Atheros madwifi-ng VAP parent: wifi0 monitor mode enabled

You will notice that ath0 is reported above as being put into monitor mode.

To confirm the interface is properly setup, enter iwconfig.

ath0 IEEE 802.11g ESSID: Nickname:

Mode:Monitor Frequency:2.452 GHz Access Point: 00:0F:B:AC:82

Bit Rate:0 kb/s Tx-Power:18 dBm Sensitivity 0/3

Retry:off RTS thr:off Fragment thr:off

Encryption key:off

Power Management:off

Link Quality 0/94 Signal level -95 dBm Noise level -95 dBm

Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0

Tx excessive retries:0 Invalid misc:0 Missed beacon:0

In the response above, you can see that ath0 is in monitor mode, on the 2.452GHz frequency which is channel 9 and the Access Point shows the MAC address of your wireless card. Only the madwifi-ng drivers show the card MAC address in the AP field, other drivers do not. So everything is good. It is important to confirm all this information prior to proceeding, otherwise the following steps will not work properly.

To match the frequency to the channel, check out: wp134132. This will give you the frequency for each channel.

Step 1b - Setting up mac80211 drivers

Unlike madwifi-ng, you do not need to remove the wlan0 interface when setting up mac80211 drivers. Instead, use the following command to set up your card in monitor mode on channel 9:

airmon-ng start wlan0 9

monitor mode enabled on mon0

Notice that airmon-ng enabled monitor-mode on mon0. So, the correct interface name to use in later parts of the tutorial is mon0. Wlan0 is still in regular managed mode, and can be used as usual, provided that the AP that wlan0 is connected to is on the same channel as the AP you are attacking, and you are not performing any channel-hopping.

To confirm successful setup, run iwconfig. The following output should appear:

wmaster0 no wireless extensions.

wlan0 IEEE 802.11bg ESSID:

Mode:Managed Frequency:2.452 GHz Access Point: Not-Associated

Tx-Power 0 dBm

Retry min limit:7 RTS thr:off Fragment thr 2352 B

Link Quality:0 Signal level:0 Noise level:0

mon0 IEEE 802.11bg Mode:Monitor Frequency:2.452 GHz Tx-Power 0 dBm

Here, mon0 is seen as being in monitor mode, on channel 9 2.452GHz. Unlike madwifi-ng, the monitor interface has no Access Point field at all. Also notice that wlan0 is still present, and in managed mode - this is normal. Because both interfaces share a common radio, they must always be tuned to the same channel - changing the channel on one interface also changes channel on the other one.

Step 1c - Setting up other drivers

For other ieee80211-based drivers, simply run the following command to enable monitor mode replace rausb0 with your interface name :

airmon-ng start rausb0 9

rausb0 Ralink rt73 monitor mode enabled

At this point, the interface should be ready to use.

Step 2 - Start airodump-ng to collect authentication handshake

The purpose of this step is to run airodump-ng to capture the 4-way authentication handshake for the AP we are interested in.

Enter:

airodump-ng -c 9 --bssid :6C:7E: -w psk ath0

Where:

-c 9 is the channel for the wireless network

--bssid :6C:7E: is the access point MAC address. This eliminates extraneous traffic.

-w psk is the file name prefix for the file which will contain the IVs.

ath0 is the interface name.

Important: Do NOT use the --ivs option. You must capture the full packets.

Here what it looks like if a wireless client is connected to the network:

CH 9 Elapsed: 4 s 2007-03-24 WPA handshake: :6C:7E:

BSSID PWR RXQ Beacons Data, /s CH MB ENC CIPHER AUTH ESSID

:6C:7E: 39 100 51 116 14 9 54 WPA2 CCMP PSK teddy

BSSID STATION PWR Lost Packets Probes

:6C:7E: 00:0F:B5:FD:FB:C2 35 0 116

In the screen above, notice the WPA handshake: :6C:7E: in the top right-hand corner. This means airodump-ng has successfully captured the four-way handshake.

Here it is with no connected wireless clients:

CH 9 Elapsed: 4 s 2007-03-24

:6C:7E: 39 100 51 0 0 9 54 WPA2 CCMP PSK teddy

Troubleshooting Tip

See the Troubleshooting Tips section below for ideas.

To see if you captured any handshake packets, there are two ways. Watch the airodump-ng screen for WPA handshake: :6C:7E: in the top right-hand corner. This means a four-way handshake was successfully captured. See just above for an example screenshot.

Use Wireshark and apply a filter of eapol. This displays only eapol packets you are interested in. Thus you can see if capture contains 0,1,2,3 or 4 eapol packets.

Step 3 - Use aireplay-ng to deauthenticate the wireless client

This step is optional. If you are patient, you can wait until airodump-ng captures a handshake when one or more clients connect to the AP. You only perform this step if you opted to actively speed up the process. The other constraint is that there must be a wireless client currently associated with the AP. If there is no wireless client currently associated with the AP, then you have to be patient and wait for one to connect to the AP so that a handshake can be captured. Needless to say, if a wireless client shows up later and airodump-ng did not capture the handshake, you can backtrack and perform this step.

This step sends a message to the wireless client saying that that it is no longer associated with the AP. The wireless client will then hopefully reauthenticate with the AP. The reauthentication is what generates the 4-way authentication handshake we are interested in collecting. This is what we use to break the WPA/WPA2 pre-shared key.

Based on the output of airodump-ng in the previous step, you determine a client which is currently connected. You need the MAC address for the following. Open another console session and enter:

aireplay-ng -0 1 -a :6C:7E: -c 00:0F:B5:FD:FB:C2 ath0

-0 means deauthentication

1 is the number of deauths to send you can send multiple if you wish

-a :6C:7E: is the MAC address of the access point

-c 00:0F:B5:FD:FB:C2 is the MAC address of the client you are deauthing

ath0 is the interface name

Here is what the output looks like:

:28 Sending DeAuth to station -- STMAC: 00:0F:B:

With luck this causes the client to reauthenticate and yield the 4-way handshake.

Troubleshooting Tips

The deauthentication packets are sent directly from your PC to the clients. So you must be physically close enough to the clients for your wireless card transmissions to reach them. To confirm the client received the deauthentication packets, use tcpdump or similar to look for ACK packets back from the client. If you did not get an ACK packet back, then the client did not hear the deauthentication packet.

The purpose of this step is to actually crack the WPA/WPA2 pre-shared key. To do this, you need a dictionary of words as input. Basically, aircrack-ng takes each word and tests to see if this is in fact the pre-shared key.

There is a small dictionary that comes with aircrack-ng - password.lst. This file can be found in the test directory of the aircrack-ng source code. The Wiki FAQ has an extensive list of dictionary sources. You can use John the Ripper JTR to generate your own list and pipe them into aircrack-ng. Using JTR in conjunction with aircrack-ng is beyond the scope of this tutorial.

Open another console session and enter:

aircrack-ng -w password.lst -b :6C:7E: psk. cap

-w password.lst is the name of the dictionary file. Remember to specify the full path if the file is not located in the same directory.

. cap is name of group of files containing the captured packets. Notice in this case that we used the wildcard to include multiple files.

Here is typical output when there are no handshakes found:

Opening psk-01.cap

Opening psk-02.cap

Opening psk-03.cap

Opening psk-04.cap

Read 1827 packets.

No valid WPA handshakes found.

When this happens you either have to redo step 3 deauthenticating the wireless client or wait longer if you are using the passive approach. When using the passive approach, you have to wait until a wireless client authenticates to the AP.

Here is typical output when handshakes are found:

BSSID ESSID Encryption

1 :6C:7E: teddy WPA 1 handshake

Choosing first network as target.

Now at this point, aircrack-ng will start attempting to crack the pre-shared key. Depending on the speed of your CPU and the size of the dictionary, this could take a long time, even days.

Here is what successfully cracking the pre-shared key looks like:

Aircrack-ng 0.8

:00 2 keys tested 37.20 k/s

KEY FOUND. 12345678

Master Key : CD 69 0D 11 8E AC AA C5 C5 EC BB 59 85 7D 49 3E

B8 A6 13 C5 4A 72 82 38 ED C3 7E 2C 59 5E AB FD

Transcient Key : 06 F8 BB F3 B1 55 AE EE 1F 66 AE 51 1F F8 12 98

CE 8A 9D A0 FC ED A6 DE 70 84 BA 90 83 7E CD 40

FF 1D 41 E1 65 17 93 0E 64 32 BF 25 50 D5 4A 5E

2B 20 90 8C EA 32 15 A6 26 62 93 27 66 66 E0 71

EAPOL HMAC : 4E 27 D9 5B 00 91 53 57 88 9C 66 C8 B1 29 D1 CB

I Cannot Capture the Four-way Handshake.

It can sometimes be tricky to capture the four-way handshake. Here are some troubleshooting tips to address this:

Your monitor card must be in the same mode as the both the client and Access Point. So, for example, if your card was in B mode and the client/AP were using G mode, then you would not capture the handshake. This is especially important for new APs and clients which may be turbo mode and/or other new standards. Some drivers allow you to specify the mode. Also, iwconfig has an option modulation that can sometimes be used. Do man iwconfig to see the options for modulation. For information, 1, 2, 5.5 and 11Mbit are b, 6, 9, 12, 18, 24, 36, 48, 54Mbit are g.

Sometimes you also need to set the monitor-mode card to the same speed. IE auto, 1MB, 2MB, 11MB, 54MB, etc.

Be sure that your capture card is locked to the same channel as the AP. You can do this by specifying -c when you start airodump-ng.

Be sure there are no connection managers running on your system. This can change channels and/or change mode without your knowledge.

You are physically close enough to receive both access point and wireless client packets. The wireless card strength is typically less then the AP strength.

Conversely, if you are too close then the received packets can be corrupted and discarded. So you cannot be too close.

Make sure to use the drivers specified on the wiki. Depending on the driver, some old versions do not capture all packets.

Ideally, connect and disconnect a wireless client normally to generate the handshake.

If you use the deauth technique, send the absolute minimum of packets to cause the client to reauthenticate. Normally this is a single deauth packet. Sending an excessive number of deauth packets may cause the client to fail to reconnect and thus it will not generate the four-way handshake. As well, use directed deauths, not broadcast. To confirm the client received the deauthentication packets, use tcpdump or similar to look for ACK packets back from the client. If you did not get an ACK packet back, then the client did not hear the deauthentication packet.

Try stopping the radio on the client station then restarting it.

Make sure you are not running any other program/process that could interfere such as connection managers, Kismet, etc.

Unfortunately, sometimes you need to experiment a bit to get your card to properly capture the four-way handshake. The point is, if you don t get it the first time, have patience and experiment a bit. It can be done.

Another approach is to use Wireshark to review and analyze your packet capture. This can sometimes give you clues as to what is wrong and thus some ideas on how to correct it. The WPA Packet Capture Explained tutorial is a companion to this tutorial and walks you through what a normal WPA connection looks like. As well, see the FAQ for detailed information on how to use Wireshark.

In an ideal world, you should use a wireless device dedicated to capturing the packets. This is because some drivers such as the RTL8187L driver do not capture packets the card itself sends. Also, always use the driver versions specified on the wiki. This is because some older versions of the drivers such as the RT73 driver did not capture client packets.

When using Wireshark, the filter eapol will quickly display only the EAPOL packets. Based on what EAPOL packets are actually in the capture, determine your correction plan. For example, if you are missing the client packets then try to determine why and how to collect client packets.

To dig deep into the packet analysis, you must start airodump-ng without a BSSID filter and specify the capture of the full packet, not just IVs. Needless to say, it must be locked to the AP channel. The reason for eliminating the BSSID filter is to ensure all packets including acknowledgments are captured. With a BSSID filter, certain packets are dropped from the capture.

Every packet sent by client or AP must be acknowledged. This is done with an acknowledgment packet which has a destination MAC of the device which sent the original packet. If you are trying to deauthenticate a client, one thing to check is that you receive the ack packet. This confirms the client received the deauth packet. Failure to receive the ack packet likely means that the client is out of transmission range. Thus failure.

When it comes to analyzing packet captures, it is impossible to provide detailed instructions. I have touched on some techniques and areas to look at. This is an area which requires effort to build your skills on both WPA/WPA2 plus how to use Wireshark.

aircrack-ng says 0 handshakes

Check the I Cannot Capture the Four-way Handshake. troubleshooting tip.

aircrack-ng says No valid WPA handshakes found

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