Category Archives: Operating System

Operating system is computer/device software used to organize how the computer work, mainly as base software that build up and connect all the computer hardware with ability to maintenance and organize how other application work.

File Permission on UNIX/Linux

Operating System, Software,

in unix/linux sistem it is easy for us to define directory or file permission. there are 3 options : read, write, execute. these options are represented with binary number rwx, respectively for read, write, execute. there are also 3 user type/level exist : user, group, other. user means the specific user logged in the system which is also the owner of the file / directory, group mean several user that has been defined on one group name, and other represent any user exist or the whole world.

each file/directory in unix/linux will be labeled by specific permission, such as drwxrwxrwx. Continue reading File Permission on UNIX/Linux →

Step by Step Backtrack Methodology

networking, Operating System

I found interesting book about backtrack and how the term penetration testing described. it is far beyond my imagination though. Here, the term penetration testing comes with words auditor, security auditor. Pentester can also become security auditor that has great responsibility to a system.

In those book i found backtrack methodology. it is actually step by step action taken by security editor in doing his penetration testing using backtrack.

those step divided into :
1. Target Scope
2. Gathering Information
3. Target Discovery
4. Enumerating Target
5. Vulnerability Mapping
6. Social Networking
7. Exploiting target
8. Privilege Escalation
9. Maintaining Access
10. Document and Reporting

Each of those processes can be done with all backtrack tools available on fresh installation of backtrack OS.
Well, i haven’t done any practical action yet actually. So later i will come up with it.

Nessus installation on Backtrack 5

hack, Operating System,

Nessus is vulnerability scanner that has web-based interface. You can use it to improve your backtrack funcionalities.

1. Install from apt-get
# apt-get install nessus

2. Follow the instruction displayed (add user). this user will be the administrator user, you can add other type of user later
# /opt/nessus/sbin/nessus-adduser

3. Register to nessus.org to get your activation code. if you have received it, run this command
# /opt/nessus/bin/nessus-fetch –register

4. if this procces doesnt run well, it may be caused by wrong proxy configuration. setting proxy configuration on nessus-fetch.rc will solve it

5. Upgrade your nessus
# apt-get upgrade nessus

6. Run nessus daemon
# /etc/init.d/nessusd start

7. Open your browser and enter https://localhost:8834/
you may login to nessus now.

Setting Static IP Address in Ubuntu / Backtrack

networking, Operating System, ,

As laptop user, we may find that we usually connect to the internet using wifi, modem, or lan cable in public rooms, we usually get an IP address from dhcp, so that we dont need to configure manually our interface address. In some occasion, for example if we want to set our ubuntu to work as a server or to be kept in permanent place we need to set its IP address to static IP.

it can be done by modifiing /etc/network/interfaces file.
for default configuration this will display these lines
(eth0 for lan card
wlan0 for wirelesscard)

auto eth0
iface eth0 inet dhcp

by basic understanding for TCP/IP
u can change it to static configuration by doing this step :
1. Edit /etc/network/interfaces file

#rootbt: nano /etc/network/interfaces

2. Change the default example to these lines

auto eth0
iface eth0 inet static
address 192.168.1.5
network 192.168.1.0
netmask 255.255.255.0
broadcast 192.168.1.255
gateway 192.168.1.1

3. Save edited file by pressing Ctrl+O
4. Restart Network just to make it sure it works
#rootbt: ifconfig eth0 down
#rootbt: ifconfig eth0 up
#rootbt: /etc/init.d/networking restart

its just example, u need to change all the number according to your own setting, ask your system administrator if you dont have any information about IP address allocation on your workplace.

How to Connect Wifi Using Command Line on Ubuntu/Backtrack

Operating System, ,

Instead of using GUI version of network manager (Wicd) we can use our command line to connect Wifi in backtrack / ubuntu. Here is the step :

1. Turn on your wireless card, (usually done by specific button).
2. Open terminal. enter command iwconfig.
bt# iwconfig
this is the example output

lo        no wireless extensions.

eth0      no wireless extensions.

wlan0     Iunassociated  ESSID:off/any
          Mode:Managed  Channel=0  Access Point: 00:00:00:00:00:00
          Bit Rate=0 kb/s   Tx-Power:off
          Retry:on   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality:0  Signal level:0  Noise level:0
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

it shows you that your wireless device’s name is wlan0

4. Do a scan
bt# iwlist wlan0 scan

5. Select ESSID dan enter its key
bt# iwconfig wlan0 essid ESSIDNAME key s:password

this will only work for wifi with WEP
for working with access point with WPA we need wpa-supplicant
read this article to read further:

http://blog.tplus1.com/index.php/2008/06/13/how-to-connect-to-a-wireless-network-from-the-ubuntu-command-line/

from those link i got this post

How to connect to a wireless network from the Ubuntu command line using a WPA/WPA2 Personal key.
For this to work.. you need to have WPA-Supplicant installed … Ubuntu comes with WPA-Supplicant installed by default.
if not present, install it using this command: sudo apt-get install wpasupplicant
Ubuntu doesn’t use a root password by default …so we need to use the sudo command here.

Now we need to create 2 files: wireless-wpa.sh + wireless-wpa.conf using the vi command. For those who are not familiar with vi , I will guide you through this.

OK ..lets start: first we gonna create the wireless-wpa.sh
type: sudo vi wireless-wpa.sh
press the “i” button ones and insert text below.
#!/bin/sh
iface=eth1

#shut down interface
ifconfig $iface down

#set ad-hoc/management of wireless device
iwconfig $iface mode Managed

#enable interface
ifconfig $iface up

#stop any persistent wireless wpa2 sessions
killall wpa_supplicant

#apply WPA/WPA2 personal settings to device
wpa_supplicant -B -Dwext -i $iface -c ./wireless-wpa.conf -dd

#obtain an IP address
dhclient $iface

Now we need to save this file and quit vi…. press “esc” button ones … then type.. :wq ( you need to type the : also )
Thats done … now we gonna make the wireless-wpa.conf

type: sudo vi wireless-wpa.conf
press the “i” button ones and insert text below.

# config file using WPA/WPA2-PSK Personal key.

ctrl_interface=/var/run/wpa_supplicant

network={
ssid=”my_router_id”
scan_ssid=1
key_mgmt=WPA-PSK
psk=”1234567890″
}

Now we need to save this file and quit vi…. press “esc” button ones … then type.. :wq ( you need to type the : also )
That’s also done … now we need to set the permissions for these 2 files.

sudo chmod 755 wireless-wpa.sh
sudo chmod 644 wireless-wpa.conf

Make sure you put these 2 files in the same directory anywhere you like…else it will not work.
Run the following command to make a connection to your wireless Router/Accespoint/
sudo ./wireless-wpa.sh

That’s all …. have fun!

from long example above i conclude that using GUI version of network manager will help us a lot.

source :
1. http://blog.tplus1.com/index.php/2008/06/13/how-to-connect-to-a-wireless-network-from-the-ubuntu-command-line/
2. https://help.ubuntu.com/community/WifiDocs/WPAHowTo

Backtrack 5 with Desktop Application

Operating System, , ,

Backtrack is generally ubuntu with various penetration-testing software and security software installed inside. It is linux distribution that focused for security testing needed, so at your fresh install you will not find any desktop application software installed. nah, becaus of this you will not able use this software to please you with standard application such as mp3 player, file reader, etc.

here some software needed to be installed after you fresh installation.
1. Internet browser : For KDE there is Konkueror installed, but u can install other internet browser such as firefox and google chrome. after u connect the internet using wicd network manager, just use apt-get to install those software
[php]
apt-get install firefox
apt-get install chromium-browser
[/php]

2. Music Player : Thera some options such as amarok, banshee, and vlc player. but unfortunately (in my case) backtrack 5 can’t play mp3 file. you can solved this problem by installing gxine with all its dependencies.

here is the command :

sudo apt-get install gstreamer0.10-pitfdll gstreamer0.10-ffmpeg gstreamer0.10-plugins-bad gstreamer0.10-plugins-bad-multiverse gstreamer0.10-plugins-ugly gstreamer0.10-plugins-ugly-multiverse gxine libxine-main1 libxine-extracodecs ogle ogle-gui

i get it from http://ubuntuforums.org/archive/index.php/t-335023.html

3. Video player : After u do the command above, any video file (must be) can be played with gxine or other software.

4. Pdf reader : thera some pdf reader avaliable such as : document viewer and xpdf, i think evince works better.
[php]
apt-get install evince
apt-get install kpdf
[/php]

5. Text editor : u can use nano (shell) as text editor but gedit should give you better view.
[php]
apt-get install gedit
[/php]

6. When i tried to open .chm file i find error occured, the software can not properly view the .chm file as it is. then i find out from google to use kchmviewer. kchmviewer is good .chm viewer for ubuntu.
[php]apt-get install kchmviewer[/php]

other software, u can easily choose it from package manager.

Setting proxy in BackTrack 5

Operating System

it is the same with usual proxy configuration in ubuntu

1. Open your shell/terminal
2. type this line

[php]
export http_proxy=http://username:pass@proxyserver:port/
export ftp_proxy=http://username:pass@proxyserver:port/
export https_proxy=http://username:pass@proxyserver:port/
[/php]

here is the example
[php]
export http_proxy=http://brian:okeydoke@cache.kampus.com:3128/
[/php]

u must change the username, password, proxyserver, and its port with your own configuration.
Ask ur sistem administrator if u dont know about it

in KDE u can also go to menu setting and choose proxy setting