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BackTrack

in your back pocketorAccessing a BackTrack server via mobile phone

in some vaguely secure way

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The Objective

Set up a Backtrack system that is accessible over the internet from thephone in my pocket. What can I say? I like to practice my metasploitsyntax while waiting in the doctor's office.

Oh, and I'd also like to do it as cheaply as possible and in somerelatively secure fashion.

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The Solution

BT4 R2 under VMWareThis would allow me to move it around as well as maintain a Known Goodsnapshot

VNC and SSHThis would allow me to access the system from any computer that had atunneling ssh client, specifically my phone

Secure ita good password, changed frequently (even better to use certificate authentication for ssh)frequent reverts to the Known Good snapshottunnel VNC through SSHchanging the default SSH port from tcp/22port knocking in order to gain access

note: sample configuration files will be in the Speaker Notes where appropriate

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First, you will need BackTrack

"BackTrack is a Linux security distribution."

"Whether youre hacking wireless, exploiting servers, performing a web applicationassessment, learning, or social-engineering a client, BackTrack is the one-stop-shop for allof your security needs.

BackTrack is a Linux-based penetration testing arsenal that aids security professionals inthe ability to perform assessments in a purely native environment dedicated to hacking."

This was all cribbed directly from their website: http://www.backtrack-linux.orgThis is also where you can download the latest release. Make sure you download the onefor VMWare. (I know. I know. It doesn't really matter for you hardcore geeks)

http://www.backtrack-linux.org/

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Why VMWare?

VMWare allows us to not have to dedicate a whole system tojust BackTrack.

BackTrack has been kind enough to provide a VMWare virtual

appliance.

VMWare also provides us the the ability to take a "snapshot" ofthe system. This means if the system ever gets breached or

you screw up configuration you can always return to your"Known Good".

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Booting up under VMWare

You can download VMWare Player for free (with registration)from: http://downloads.vmware.com/

Extract the BackTrack files and open up the one with the ".vmx"

extension.

Login with userid: root / password: toor

No need to start XWindows, but if you really want to, type: startx

http://downloads.vmware.com/http://downloads.vmware.com/

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'toor'? Really? You gonna keep that?

The default password is 'toor'. Change this immediately with:

passwd

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Configure the local firewall

We want to setup the BackTrack firewall to block all but

necessary traffic. You will need to decide now which ports youare going to use for port knocking and ssh. In this example wewill use the following:

port knocking: tcp/1111, tcp/2222, udp/3333ssh: tcp/4444

Feed your config file to iptables-restoreiptables-restore < /etc/iptables.rules

* sample configuration file in the Speaker notes

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Enable Networking

The BackTrack server is configured for DHCP, but the

interface is disabled by default. You can enable it with:

/etc/init.d/networking start

For static IP address you will need to edit:vi /etc/network/interfaces*

You can set networking to auto-start on a reboot with:

update-rc.d networking defaults

* sample configuration file in the Speaker notes

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Update BackTrack

Now that we have internet access, it's a good time to get theOS up to date.

apt-get -y update

apt-get -y upgradeapt-get clean

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Enable and configure SSHSSH will be your primary access to BackTrack. Luckily most of the tools you will

use in BackTrack are run from command-line anyway.

Edit the config file to change the default SSH port.vi /etc/ssh/sshd_config*

Generate your ssh encryption keys (Do not enter passphrases)

ssh-keygen -t dsa -f /etc/ssh/ssh_host_dsa_keyssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key

Start the ssh server and set it to auto-start on a reboot/etc/init.d/ssh startupdate-rc.d ssh defaults

* sample configuration file in the Speaker notes

Advanced configuration using certificate basedauthentication is at the end of this presentation

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Port KnockingYou can think of port knocking as a "secret knock" used toremotely open and close the ssh port.

Backtrack will start with all ports closed. After you send it aspecial sequence of packets, the port knock server will issue acommand to open the ssh port. After you are finished using

ssh, you send it a different sequence to close the port again.

We will use knockd as our port knock server.

http://www.zeroflux.org/projects/knockhttp://www.portknocking.org/

http://www.zeroflux.org/projects/knockhttp://www.portknocking.org/http://www.zeroflux.org/projects/knock

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Port Knocking install and configuration

To install knockd:apt-get install knockd

Edit the config file to set-up the ports you want to use:

vi /etc/knockd.conf

Start knockd in daemon mode:knockd -d -i eth0

Is this just "security through obscurity"?

* sample configuration file in the Speaker notes

http://www.portknocking.org/view/about/obscurityhttp://www.portknocking.org/view/about/obscurity

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Start VNC

Even though we will rarely use a gui or XWindows, why nothave it? At the very least, it looks more impressive when youshow off.

Start VNC (you will be prompted to set a password):vncserver

We will access VNC through an SSH tunnel.

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Take a picture, it'll last longer

Take a VMWare snapshot and call it "Known Good". Every nowand again you can restore this snapshot in VMWare and comeback to exactly this point in your configuration.

VM -> Snapshot -> Take Snapshot

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Dynamic DNS

If you don't have a static IP address you will probably want tosetup dynamic DNS on host. This is a free service that will keepa hostname always registered to whatever your current, ISPassigned, IP address. You can run the client on any machine

behind your router. There are many options. Here are two:

http://www.dyndns.com/services/dns/dyndns/http://www.no-ip.com/

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Configure the your Internet routerYour internet or wireless router will need to be configured to

forward external ports for both SSH and port knocking to theBackTrack system. This is usually available in your routeradministration.

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Client side

That is it for the server. You now have it configured for portknocking, ssh, vnc and remote access over the internet.

Now it's time to configure the client. You will need two clients.

One for port knocking and one for ssh/vnc.My examples will be for the iPhone, but most smart phones willhave these types of clients available. Links for Android clientsare listed later.

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iPhone:Install and configure KnockOnD

I chose KnockOnD as my port knocking client. Mainly because

it's free, ad free and it works.

http://bluezbox.com/knockond.html

http://bluezbox.com/knockond.html

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iPhone : Install and configure iSSH

iSSH is not free. As of this writing it's about 10$USD. But it has

benefits that the others do not have. Not the least of which isthat it allows for tunneling VNC.

http://www.zinger-soft.com/iSSH_features.html

http://www.zinger-soft.com/iSSH_features.html

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Android clients

For ssh/vnc use ConnectBot

ConnectBot

For port knocking use knock-androidKnock-Android

http://code.google.com/p/knock-android/downloads/detail?name=PortKnocking-0.2.6.apk&can=2&q=%20http://code.google.com/p/connectbot/

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Amaze your Friends and Family

Amaze yer friends with your incredible 500P3R L337 H4X0R skills

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TroubleshootingFlush all iptables rules

/sbin/iptables --policy INPUT ACCEPT/sbin/iptables --policy OUTPUT ACCEPT/sbin/iptables --policy FORWARD ACCEPT/sbin/iptables -F

verify SSH is working without the rulesverify knockd, ssh, vnc are running

ps ax | grep knockd

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Troubleshootingverify ports

netstat -anverify iptables

iptables -L -n

kill processeskillall knockdkillall sshdvncserver -kill :1

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Advanced: SSH Certificate AuthenticationServer setup

Change into your local .ssh config directorycd /root/.ssh

Generate a RSA key pair (make sure to set a password)ssh-keygen -v -t rsa

Authorize the key for 'root' access to the ssh server

cp id_rsa.pub authorized_keys

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Advanced: SSH Certificate AuthenticationClient setup

Copy your public key to an iPhone note.cat /root/.ssh/id_rsa

Sync your iPhone and copy the note to youriPhone clipboard.Import (Paste) it to iSSH from

General Settings > Configure SSH Keys> Import Key...

Change your Connection to "Use Key"authenticationVerify connectivity

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Advanced: Disable Password AuthenticationServer setup

Edit the /etc/ssh/sshd_config*PasswordAuthentication noChallengeResponseAuthentication no

Edit the config file to change the default SSH port/etc/init.d/ssh restart

* sample configuration file in the Speaker notes

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Thanks

I hope you found this useful. The original version of this presentation can befound at:

https://docs.google.com/present/view?id=djjg73z_45k2rdzkzt

https://docs.google.com/present/view?id=djjg73z_45k2rdzkzt