Happy Vijaya Dashami 2069

Techgaun team would like to wish all our site visitors happy vijaya dashami 2069. May this dashain bring peace and prosperity in everyone's life and may the world be more peaceful place than ever.

I would like to include blessings (ashirbad / आशिर्वाद) offered during Dashain.

The mantra below is enchanted when elders offer tika to male member:

आयुर द्रोण सुते श्रेयम दशरथे , सत्रुक क्षेयम रघवे, ऐश्र्वर्यम नहुशे , गतिस्च पवने, मानन्च दुर्योधने, सौर्यम शान्त नवे, बलम हलधरे , सत्यस्च कुन्तीसुते , बिज्ञ।न बिदुरे, भवन्तु भबताम, किर्तिस्च नारायणे!

Ayur Drona sute sriyem Dasarathe, Satruk ksheyam Raghave, Yaishoryem Nahushe, Gatischa pawane, Manancha Duryodhane, Suaryam Shanta nave, Balam Haldhare, Satyaschha Kuntisute, Bigyanam Bidure, Bhawanu Bhabatam, Kirtischha Narayane!

The mantra below is enchanted when the tika is offered to the female members:

ॐ जयन्ती मङ्गला काली भद्रकाली कपालिनी । दुर्गा क्ष्यमा शिवा धात्री स्वहा स्वधा नमोस्तु ते ।।

Om Jayanti Mangala Kaali Bhadra Kali Kapalini Durga Kshyama shiva dhatri swaha swadha namostu te

Happy Vijaya Dashami 2069

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Reverse Shell Backdoor Cheatsheets Collection

Once you find your way to command execution after exploiting any of the flaws in web-apps, you look for interactive shell. You can do so by binding shell in some port or using reverse shell backdoor. Here are few links with awesome backdoor cheatsheet collections for obtaining reverse shell using different scripting languages:

PentestMonkey's Cheatsheet

Bernardo's Reverse Shells One-liners

GNU Citizen

In case you can't access pentest monkey, below is the cheatsheet in PNG format:

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Ubuntu Tweak Development Will Continue

Three days ago, Ubuntu Tweak developer Tualatrix had posted a blog post mentioning that the Ubuntu Tweak will no longer be developed but he has now changed his mind and has decided to continue the development because of support he received.

The developer writes
You made me know that Ubuntu Tweak is still valuable, and as the first software project I made 5 years ago, it is just like my baby, I don’t really want to give up the development.

and thanks all the good people who left the message for him and forked the app in github.

The blog post also mentions
Back to 5 years ago, I developed it just because of my practice on Linux programming, I felt freedom when I make things on Linux (Although I didn’t have developing experience on Windows and Mac then). But now I don’t feel any freedom about developing this software any more. The initial motivation is changed, and I’m still looking for new motivation.

Overall, he is not too satisfied with his current overload for working on this personal project while still managing time for his job and personal life.

Anyway, Ubuntu Tweak 0.8.1 is out and you can download from PPA.

PPA DEB link

Release Notes


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Ninja Fu With Netcat - Hacker's Swiss Army Knife

Netcat is one of my favorite tools for network investigations and backdoor planting. Netcat is a seemingly simple but very powerful and useful tool to read and write network connections using TCP or UDP. In this post, we will see several examples of using netcat in different scenarios.

First of all, if you are using distros like Ubuntu, they are probably including the OpenBSD netcat which does not provide a very useful switch that lets us execute any command. The netcat-traditional offers this switch so for learning purpose, you should install the netcat-traditional package by issuing the command below in Ubuntu & its derivatives (However, beware of inherent risk with this feature of the traditional netcat):

samar@samar-Techgaun:~$ sudo apt-get install netcat-traditional

Now you can use both OpenBSD and traditional versions by using nc.openbsd and nc.traditional respectively. However, the nc command might still be symbolically linked with nc.openbsd (/etc/alternatives/nc). If you want to permanently use nc to refer nc.traditional, type the following command (or do sudo rm /bin/nc && sudo ln -s /bin/nc.traditional /bin/nc):

samar@samar-Techgaun:~$ sudo update-alternatives --config nc

As I had already said, netcat is a very useful tool for network related works and hence often referred as Hacker's Swiss Army Knife and TCP/IP Swiss Army Knife. You can use netcat for several purposes such as file transfer, port scanning, listen server, bind & reverse shells, backdoors, etc. Because of this, netcat has been a favorite tool for hackers to get and maintain access to the servers.

Before beginning with the examples, I would like to inform you that most of the times ports above 1024 are used to create listen servers with netcat. This is because ports below 1024 are reserved by OS for core network services and you can not bind to these ports without special privilege to the system.

Simple Netcat Listen Server

samar@samar-Techgaun:~$ nc -lvp 1234
listening on [any] 1234 ...

Simple Netcat Client

samar@samar-Techgaun:~$ nc -vvn 192.168.1.6 1234
(UNKNOWN) [192.168.1.6] 1234 (?) open

Once the client gets connected, the netcat listener might then look like this:

samar@samar-Techgaun:~$ nc -lvp 1234
listening on [any] 1234 ...
connect to [192.168.1.6] from samar-Techgaun.local [192.168.1.6] 38700

Noticed the port 38700 in the end? This is the port that the client uses to talk with the server. Observe that the value is much higher than 1024 and hence such ports are known as ephemeral port.

Once the client and server get connected, you can write anything and press ENTER. The data will get transmitted to the other end thus making netcat a data transfer tool.

Open Raw Connection With Netcat as client

samar@samar-Techgaun:~$ nc -vv ku.edu.np 80
Warning: inverse host lookup failed for 116.90.239.5: Unknown host
ku.edu.np [116.90.239.5] 80 (http) open
HEAD / HTTP/1.0\n\n

HTTP/1.1 200 OK
Date: Mon, 22 Oct 2012 04:46:49 GMT
Server: Apache/2.2.3 (CentOS)
X-Powered-By: PHP/5.1.6
Connection: close
Content-Type: text/html; charset=UTF-8

sent 21, rcvd 171

As seen above, I opened the RAW connection to ku.edu.np and then issued HEAD / HTTP/1.0\n\n request to obtain the HTTP header. You can also notice (see web server version & PHP version?) that netcat can be used for basic fingerprinting and banner grabbing. Of course, this is not limited to HTTP fingerprinting. Extend the idea to work with other services.

Web Server Example Using Netcat

samar@samar-Techgaun:~/Desktop/test$ { echo -ne "HTTP/1.0 200 OK\r\nContent-Length: $(wc -c < my_file)\r\n\r\n"; cat my_file; } | nc -lv -p 8080
listening on [any] 8080 ...

This example taken from Wiki entry works as a one shot webserver hosting the my_file's content which can be accessed through web browser by specifying http://server:8080.

File Transfer Using Netcat

To transfer file from server to client, set up the server as below:

samar@samar-Techgaun:~$ cat my_file
I am DATA
samar@samar-Techgaun:~$ nc -lvp 1234 < my_file
listening on [any] 1234 ...

In the client end, do:

samar@samar-Techgaun:~$ nc -vv 192.168.1.6 1234 > output.txt
samar-Techgaun.local [192.168.1.6] 1234 (?) open
^C sent 0, rcvd 10
samar@samar-Techgaun:~$ cat output.txt
I am DATA

Port Scanning With Netcat

samar@samar-Techgaun:~$ nc -nvz -w1 192.168.1.1 1-1024
(UNKNOWN) [192.168.1.1] 80 (http) open
(UNKNOWN) [192.168.1.1] 23 (telnet) open
(UNKNOWN) [192.168.1.1] 21 (ftp) open

If you wish to scan number of hosts (or full network), you can do something like below:

samar@samar-Techgaun:~/Desktop/test$ for ip in $(seq 1 254); do nc -nvz -w1 192.168.1.$ip 1-1024; done

In the first example, ports 1-1024 are scanned in the host 192.168.1.1 and in the second example, a class C network 192.168.1.0/24 is scanned. However, netcat is by no means an advanced port scanner and tools such as nmap are great for this job.

Spawn a process

The -e switch can be specified to spawn a process in the system. In the server, type the command below:

samar@samar-Techgaun:~$ nc -lv -p 1234 -e /bin/bash
listening on [any] 1234 ...

At the other end, you will just connect to the just started netcat service and then issue any command that the bash recognizes. Good for shells in the servers, isn't it?

samar@samar-Techgaun:~$ nc -vv 192.168.1.6 1234
samar-Techgaun.local [192.168.1.6] 1234 (?) open
ls
my_file
output.txt

Netcat backdoor using mkfifo

Since the normal pipe (|) is not so reliable & works in a unidirectional fashion, linux offers something called named pipes which can be exploited to create advanced backdoor in the systems which might not consist the netcat with -e support.

samar@samar-Techgaun:~$ mkfifo /tmp/b4ck; sh /tmp/b4ck | nc -lvp 1234 > /tmp/b4ck
listening on [any] 1234 ...

At the other end, you just need to connect to the newly created netcat service port:

samar@samar-Techgaun:~$ nc -vv 192.168.1.6 1234
localhost [192.168.1.6] 1234 (?) open
ls
my_file
output.txt
sent 3, rcvd 33

I hope this post provides some directions on how to work with netcat and proves that netcat is called TCP/IP swiss army knife for the reason. There are other several possibilities with netcat. Explore to get more out of this awesome tool. ;)


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Ubuntu Studio - Ubuntu Derivation For Audio Video & Graphics Editor

Ubuntu Studio is a variant of Ubuntu aimed at the GNU/Linux audio, video and graphic enthusiast as well as professional. The distribution provides a collection of open-source applications available for multimedia creation. Ubuntu Studio is a free, open source and powerful operating system created for the creative people to create exceptional arts using right sets of tools for audio, video and graphical editing. As an officially recognized derivative of Ubuntu, Ubuntu Studio is supported by Canonical Ltd.

Ubuntu Studio is released every six months, but a long term release (LTS) version is released only every 2 years.

Audio apps include Jack, Ardour, Audacity, QTractor, Hydrogen, Yoshimi, Rakarrack, Gladish, Puredata and several other apps available for download.

Graphical apps include Blender, Inkscape, GIMP, MyPaint and several other apps.

Video apps include Openshot video editor, FFMPEG, DVDStyler, and other apps.

Photography apps include Darktable, Shotwell, and several other useful apps.

Calibre, Scribus and LibreOffice and other apps are available to suffice publishing needs.

Useful Links

Ubuntu Studio HOME

Ubuntu Studio Download

Ubuntu Studio Documentation


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Enable Auto Correction Of Path In Bash

While using the cd command, its normal to make mistakes while typing the directory path. You can enable auto-correction while typing directory path by enabling a particular shell option.

Minor spelling mistakes will be corrected automatically if the particular shell option cdspell using the SHell OPTions command invoked with shopt command.

When you enable the cdspell shell option, the errors checked for are missing characters, repeated characters, and transposed characters. Once the error is encountered, the corrected path is printed and directory is changed successfully.

samar@samar-Techgaun:~$ shopt -s cdspell
samar@samar-Techgaun:~$ cd Desktp
Desktop
samar@samar-Techgaun:~/Desktop$ cd ../Deskotp/
../Desktop/
samar@samar-Techgaun:~/Desktop$ cd ../Desktoop
../Desktop
samar@samar-Techgaun:~/Desktop$

The line shopt -s cdspell enables the auto-correction while using cd command. The session above shows some of the corrections performed once we enabled the cdspell shell option.

If you want to turn on this particular setting, then add the appropriate line using the command below:

samar@samar-Techgaun:~$ echo "shopt -s cdspell" >> ~/.bash_profile

I hope this counts as useful tips to beginner linux guys ;)


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Ubuntu Tweak Will No Longer Be Developed

Comes as a very sad news but Ubuntu Tweak developer has decided to stop the development of Ubuntu Tweak. Tualatrix Chou writes in a blog post:

" I want to stop the development and maintenance of Ubuntu Tweak. This means you will not be able to use “Apps” (Since it is a web service), I will not response for the bug report, the last commit of the code will be: Add cache support for Apps, only available in Ubuntu 12.10, so sad".

While the developer writes the reason as If making free software is not free any more, why still doing this?, I found the whole post quite cryptic.

One of his friend mentions that Ubuntu Tweak, though being a great app has not been included in the official source which is a really depressing thing.


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Practical ls Command Examples For Fun & Profit

The power of linux lies in the shell through which we can perform complex job in no time. While the directory listing command 'ls' seems to be very simple command, the linux shell provides the power to use switches and pipes to do anything from terminal. Check out this list with practically useful examples using ls.

Display all files including hidden files/folders

ls -a

Display one file/folder per line

ls -1

Count number of files & folders

ls -1 | wc -l

Human readable file sizes (eg. Mb or Gb)

ls -lh

Alphabetically sort the listing

ls -X

Only list the folders in current directory

ls -d */
ls -p | grep /

Display folders in current directory consisting certain patterns

ls -l D* | grep :$
ls -l *a* | grep :$

List files by descending order of modification time

ls -lt
ls -l --sort=time #alternative long version

List files by descending order of creation time

ls -lct

List files in reverse order

ls -ltr
ls -l --sort=time --reverse #alternative long version

List files in descending order of file size

ls -lSh
ls -lh --sort=size
ls -lSh1 *.avi #find largest AVI file
rm `ls -S1 | head -1` #delete largest file in current folder

List files in ascending order of file size

ls -lShr
ls -lh --sort=size --reverse #alternative long version

Display directories in recursive manner

ls -R

Display the files/folders created today

ls -l --time-style=+%F | grep `date +%F`

Display the files/folders created this year

ls -l --time-style=+%y | grep `date +%y`

Any more example that fires up in your mind? Feel free to share over here ;)


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