AWG Blogs

Saturday, July 4, 2009

udp_scan on Debian 4

Download & Setup:

lftp -c 'open -e "mget port-scan*" ftp.porcupine.org/pub/security'
tar zxvf port-scan.tar.gz
cd port-scan
make CFLAGS=-D_BSD_SOURCE

There will be some errors.

Then, run udp_scan on target:
./udp_scan 10.10.10.10 1-1024

Note: udp_scan also comes with the SATAN package (and its successors).

Installing SATAN 1.1.1 on Debian 4.0

wget http://www.ibiblio.org/pub/packages/security/Satan-for-Linux/satan-1.1.1.linux.fixed2.tgz

unpack in /tmp and cd to satan-1.1.1

edit reconfig:

sed -i 's/version 5/v\(ersion \)\?5/' reconfig

if no dev environment:

apt-get install make
apt-get install build-essential

then:

perl reconfig
make linux

run:

./satan

Wednesday, July 1, 2009

vtund Experimentation part 3 - Bridging

Picking up from "vtund Experimentation part 2" we are going to set up the bridge interface, which will bridge tap0 and eth1 as depicted in http://blog.kovyrin.net/2006/04/05/connecting-two-remote-local-networks-with-transparent-bridging/ (although there it's eth0).

On both server and client sever the vtund connection (if any) and kill the vtund process.

On the server:
in the lion config of vtund-server.conf, replace
"ifconfig "%% 10.1.0.1 netmask 255.255.255.0";
with the following lines:
ifconfig "%% up";
program "brctl addif br0 %%";
comment out the route command.
change the password (recommended)

On the client:
in the lion config of vtund-client.conf, replace
"ifconfig "%% 10.1.0.2 netmask 255.255.255.0";
with the following lines:
ifconfig "%% up";
program "brctl addif br0 %%";
change the password to same as server's (if changed on server).

On the server:
in /etc/network/interfaces
remove the eth1 ip configuration, except for the line
auto eth1 # to bring up eth1
Add the br0 ip configuration:
iface br0 inet static
address 192.168.100.99
netmask 255.255.255.0
bridge_ports eth1

On the client:
in /etc/network/interfaces
remove the eth1 ip configuration, except for the line
auto eth1 # to bring up eth1
Add the br0 ip configuration:
iface br0 inet static
address 192.168.100.100
netmask 255.255.255.0
bridge_ports eth1

On both server and client bring up br0:
ifup br0

On the server:
vtund -n -s -f /etc/vtund-server.conf

Then on client:
vtund -n -f /etc/vtund-client.conf lion server_public_ip_address

With luck, a UDP connection (tunnel) will be initialized. From client you should be able to ping 192.168.100.99 (server's br0 ip address).

On the server, type
brctl show
results:

bridge name bridge id STP enabled interfaces
br0 xxxxxxxx no eth1
tap0


Now set up another machine on the 192.168.100.x network on either side and ping both machines from it. If the machines can't ping eachother, ensure that the switch (vSwitch if in VMware) is set to Accept in Promiscuous Mode Policy Exceptions.

(see also Building Linux Virtual Private Networks (VPNs) on Google Books for example of the Ethernet Tunnel)

vtund Experimentation part 2

On both client and server:
fresh stable (ubuntu LTS 8.04) Ubuntu, get all updates.
then apt-get install bridge-utils (per http://blog.kovyrin.net/2006/04/05/connecting-two-remote-local-networks-with-transparent-bridging/)
then:
apt-get install uml-utilities
tunctl -u root -t tap0
ifconfig tap0 0.0.0.0 promisc up

then apt-get install vtun

modprobe tun

Then on server, copy /usr/share/doc/vtun/examples/vtund-server.conf to /etc
comment out: bindaddr { iface lo; };
in lion configuration:
change: "compress lzo:9;" to "compress no;"
change: "encrypt yes;" to "encrypt no;"
comment out firewall lines

Then on client, copy /usr/share/doc/vtun/examples/vtund-client.conf to /etc
edit /etc/vtund-client.conf: under the "lion" configuration, change "device tap1" to "device tap0"

Then on server:
edit /etc/network/interfaces:
auto lo
iface lo inet loopback

iface eth0 inet static
address public_ip_address
netmask public_mask
gateway public_gateway
auto eth0

Then on client:
edit /etc/network/interfaces:
auto lo
iface lo inet loopback

iface eth0 inet static
address public_ip_address
netmask public_mask
gateway public_gateway
auto eth0

Then on server:
vtund -n -s -f /etc/vtund-server.conf

Then on client:
vtund -n -f /etc/vtund-client.conf lion server_public_ip_address

With luck, a UDP connection (tunnel) will be initialized. From client you should be able to ping 10.1.0.1 (server's tun0 ip address).