First, you guys are so lazy its rediculous. That said...
Originally Posted by Sharper
There will be occasions that even though it says you are associated and the keep alive packets are flowing nicely, the association breaks. So you might have to stop and rerun the command.
With some drivers, the wireless card MAC address must be the same as MAC address you are injecting. So if fake authentication is still not working then try changing the card MAC to the same one you are trying to authenticate with. A typical package to do this is macchanger. Search the forums or the internet for the details and other options. Changing the MAC address is beyond the scope of this tutorial. See How do I change my card's MAC address?
Some access points are configured to only allow selected MAC access 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. Thus ,the advantage of the next technique (interactive replay) is that it gets around this control.
To determine if MAC access control is in place, enter the following command:
"You will have to change “00:c0:ca:17:db:6a” to the injection MAC address. It is case sensitive and typically lowercase. You may need to look at the tcpdump output without the grep filter to verify the case.
tcpdump -n -vvv -s0 -e -i ath0 | grep -E "(RA:00:c0:ca:17:db:6a|Authentication|ssoc)
When you are trying to do fake authentication, the exchange should look identical to the wep.open.system.authentication.cap file which comes with the aircrack-ng software. This file can be read into tcpdump as...
Basically you should see two authentication packets and then two association packets. If your real life capture does not contain all four packets and your fake authentication is failing then there is a MAC filter in place. In this case, you must use the MAC address of a client already associated with the AP. To do this, change the MAC address of your card to it. See How do I change my card's MAC address?
tcpdump -n -e -vvv -r wep.open.system.authentication.cap
A normal MAC address looks like this: 00:09:5B:EC:EE:F2. The first half (00:09:5B) of each MAC address is the manufacturer. The second half (EC:EE:F2) is unique to each network card. Many access points will ignore invalid MAC addresses. So make sure to use a valid wireless card manufacturer code when you make up MAC addresses. Otherwise your packets may be ignored.
Here is an example of what a failed authentication looks like:
An alternate approach is to replay packets from a wireless client which is currently associated with the AP. This eliminates the need to use fake authentication since you be piggy backing on client MAC address which is already associated with the AP.
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 RequestNotice the “Got a deauthentication packet” and the continuous retries above.
Use the interactive replay attack instead. We are going to look for an arp packet coming from an already associated wireless client going to the access point. We know that this arp packet will be rebroadcast by the AP and generate an IV. ARP packets coming from a wireless client are normally 68 bytes long with a broadcast MAC address.
So we construct a request which selects the packets we are looking for:
Where: -d FF:FF:FF:FF:FF:FF - broadcast - m 68 - minimum packet length of 68 - n 68 - maximum packet length of 68 - t 1 - packet is going to the access point - f 0 - packet is not coming from the access point
aireplay-ng -2 -a <bssid MAC address> -d FF:FF:FF:FF:FF:FF -m 68 -n 68 -t 1 -f 0 <interface>
This will display each packet captured for you to inspect before being used. Just ensure the packet you select is one of the wireless clients already associated with the access point.
Here is an example:
Some access points have a setting to disable wireless client to wireless client communication (called at least on Linksys “AP isolation”). If this is enabled then all the techniques above will not work. The only approach is to use the techniques outlined in another one of my tutorials: How to crack WEP via a wireless client.
aireplay-ng -2 -a 00:14:6C:7E:40:80 -d FF:FF:FF:FF:FF:FF -m 68 -n 68 -t 1 -f 0 ath0
Read 202 packets...
Size: 68, FromDS: 0, ToDS: 1 (WEP)
BSSID = 00:14:6C:7E:40:80
Dest. MAC = FF:FF:FF:FF:FF:FF
Source MAC = 00:0F:B5:AB:CB:9D
0x0000: 0841 d400 0014 6c7e 4080 000f b5ab cb9d .A....l~@.......
0x0010: ffff ffff ffff a00f 010a dd00 a795 2871 ..............(q
0x0020: 59e5 935b b75f bf9d 718b d5d7 919e 2d45 Y..[._..q.....-E
0x0030: a89b 22b3 2c70 b3c3 03b0 8481 5787 88ce ..".,p......W...
0x0040: b199 6479 ..dy
Use this packet ? y
Saving chosen packet in replay_src-0124-120102.cap
You should also start airodump-ng to capture replies.Although you can’t see it, the above command started generating the IVs. As usual, run airodump-ng and aircrack-ng.