Setup a Fake Accesspoint with BackTrack 5

Recently I needed to setup a fake access point for a presentation, I fired up my Backtrack5 VM, Connected my Alfa AWUS036H USB adapter and started to configure the Fake AP.

There are a lot of Tutorials and Scripts for setting up a Fake AP,  The “Gerix”  tool also have an option to auto set a Fake AP (for some reason this tool never worked for me).

I started to setup my fake AP and had run into some trouble for a strange reason.

I decided to put my experience here hopefully you’ll find it useful.

Started by putting my Wlan interface in monitor mode

root@Blackbox:~/fakeap# 

I noticed the following error: “Unknown error 132″
Tried using airodump-ng to see what happens…

root@Blackbox:~/fakeap# 

Got the same error.

The solution was simply to unload the RTL8187 and Load the R8187 driver instead as follows:

root@Blackbox:~/fakeap# 

Tried putting wlan In monitor mode again

root@Blackbox:~/fakeap# 

Well, that fixed the problem

root@Blackbox:~/fakeap# 

Now we can proceed to the fake ap setup process

1. Install a DHCP Server

apt-get install dhcp3-server

2. Edit “/etc/dhcp3/dhcpd.conf” as follows (You can change ip address, pool and dns server as needed):

ddns-update-style ad-hoc;
default-lease-time 600;
max-lease-time 7200;
authoritative;
subnet 10.0.0.0 netmask 255.255.255.0 {
option subnet-mask 255.255.255.0;
option broadcast-address 10.0.0.255;
option routers 10.0.0.254;
option domain-name-servers 8.8.8.8;
range 10.0.0.1 10.0.0.140;
}

3. Put your wlan in monitor mode

airmon-ng start wlan1

4. Start airbase-ng, you will need to specify the AP SSID and channel number

airbase-ng -e FreeWifi -c 11 -v wlan1 &

5. Airbase will create a new adapter “at0″ you will need to enable it and assign it with an ip address and subnet mask, the ip address you assign to this interface will be the default gateway that you specified in the dhcpd.conf file.

ifconfig at0 up
ifconfig at0 10.0.0.254 netmask 255.255.255.0

6. Add a route

route add -net 10.0.0.0 netmask 255.255.255.0 gw 10.0.0.254

7. Setup ip tables

iptables --flush
iptables --table nat --flush
iptables --delete-chain
iptables --table nat --delete-chain
iptables -P FORWARD ACCEPT

• Eth3 is my external interface which is connected to the internet change it to whatever yours is

iptables -t nat -A POSTROUTING -o eth3 -j MASQUERADE

8. Clear dhcp leases

echo > '/var/lib/dhcp3/dhcpd.leases'

9. Create a symlink to dhcpd.pid (skipping this may cause an error when starting dhcp server)

ln -s /var/run/dhcp3-server/dhcpd.pid /var/run/dhcpd.pid

10. Start the DHCP server

dhcpd3 -d -f -cf /etc/dhcp3/dhcpd.conf at0 &

11. Don’t forget to enable IP forwarding

echo "1" > /proc/sys/net/ipv4/ip_forward

That’s All Folks!

I have created a simple bash script to automate this process you will just need to change it  to suit your configuration.