NamHuy » Ubuntu

Linux defacements and Linux hacking

Huy Tran — Tue, 15 Nov 2011 17:36:26 +0000

Zone-h.org has an excellent site to see defacements and what is going on across the internet. Reviewing the archives and live defacements, Linux is defaced (hacked) more times than Windows. What exactly does this mean? Is Linux unsafe? Not at all. It truly falls on the administrator who configured Linux. There is a false sense of security when you install Linux based on all of the sites and forums that support Linux’s ability to be safe and reliable. Truly it can be the safest if the following holds true -

Proper configuration
Updates
Reading materials
Frequent penetration tests
Monitoring and logging
Experience with advanced configurations

Zone-h archives

All operating systems have vulnerabilities. And yes Apple, Microsoft and Linux is only as safe as the end user.

Install all programs on a newly installed ubuntu system

Huy Tran — Fri, 22 Jul 2011 20:51:17 +0000

If you’re running Ubuntu there is a neat way of installing all of your programs on a newly installed Ubuntu system.
Run the following command on the ‘old’ Ubuntu installation.
“dpkg –get-selections > installed-software”

You’ll end up with a file called installed-software. Copy the file to a usb key and copy it to a location on your backtrack machine.
Run: “dpkg –set-selections < installed-software” in the directory where you copied the file installed-software.
Finally the “sudo apt-get dselect-upgrade” commands completes all of this. Be aware that is might take while until the installtion finishes.

If the above doesn’t work, you probably do not have dselect installed.
In that case, run “apt-get install deselect”
The above instructions also work on BackTrack 5

Clearing Ubuntu Cache Memory

Huy Tran — Sat, 16 Jul 2011 23:09:17 +0000

Did a search for help on clearing up Ubuntu’s Cache System as my system keeps using up my memory for cache system. Though using up my memory for cache doesn’t actually hinder my system’s operation, I find it quite irritating to see it being used up even though I have 8GB of RAM. This command should work for most Debian based Linux Operating System, but I haven’t try them as I don’t own any now. Here is the link to the document.

Before using the below commands, do a sync to flush any cache data to the disk so data that’s required isn’t lost.

To free pagecache:
echo 1 > /proc/sys/vm/drop_caches

To free dentries and inodes:
echo 2 > /proc/sys/vm/drop_caches

To free pagecache, dentries and inodes:
echo 3 > /proc/sys/vm/drop_caches

how to add proftpd user to /var/www

Huy Tran — Fri, 19 Nov 2010 01:43:54 +0000

Here is how you add an user to ftp server on Ubuntu LAMP (Linux, Apache, MySQL, PHP).

chown username /var/www/username

or chown username /var/www

Terminal or shell command to shutdown or reboot Ubuntu Linux

Huy Tran — Wed, 03 Nov 2010 23:05:35 +0000

So how do you shutdown or reboot Ubuntu Linux from a terminal or a shell prompt? If GUI is working you can always click on a Quit button. If GUI is not working or if you are working remotely over ssh type the following command:

To shutdown / poweroff Ubuntu Linux
Type the command:
sudo halt
OR
sudo shutdown -h now

To reboot Ubuntu Linux
Type the command:
sudo reboot

More information can be found about these two commands by typing following commands (man page):
man reboot
man shutdown

XEphem on Ubuntu

Huy Tran — Mon, 25 Oct 2010 22:16:58 +0000

XEphem is an outstanding software for astronomers.It is written in C and there aren’t any packages built for it so you have to compile it using the source codes.
When building on Ubuntu, it is most likely that you’ll get some error messages, because need some libraries not included in Ubuntu by default.
Download the source code and extract it.

$ wget http://97.74.56.125/free/xephem-3.7.4.tar.gz

$ tar -xvf xephem-3.7.4.tar.gz

Before compiling, we need these packages installed.

$ sudo apt-get install libmotif3 libmotif-dev x11proto-print-dev libxp-dev libxmu-dev

If you don’t install these packages, you’ll get errors during compilation from various files, like aavso.c

Now let’s compile!

$ cd xephem-3.7.4/GUI/xephem

$ make MOTIF=../../libXm/linux86

(NOTE : If you’re using an x86_64 system, use MOTIF=/usr/lib as make the option since the libXm delivered with xephem won’t do any good for you)
The rest is as stated in the INSTALL file.

List of things to be done after every Ubuntu install

Huy Tran — Sun, 17 Oct 2010 08:03:23 +0000

Here is a list of things that I must do every time I upgrade my Ubuntu version.

Create root password
Install multimedia codecs to play songs and other files
Install VLC and Mplayer
Install new graphic and sound drivers if available
Install new version of Mozilla Firefox
Install Gimp (Ubuntu 10.04 LTS)
Install Mozilla Thunderbird
Install Microsoft Windows Fonts
Install Skype
Install Xorg-edit
Install TeamViewer

Disable one of two built in Wifi cards Ubuntu

Huy Tran — Fri, 01 Oct 2010 17:43:18 +0000

$sudo lshw -C network

$sudo lsmod

shows us that the driver to blacklist is rt73usb.

Then add

blacklist rt73usb

to /etc/modprobe.d/blacklist.

Stop CPU beep in Ubuntu-Debian

Huy Tran — Sun, 26 Sep 2010 17:40:36 +0000

The CPU beep is a really irritating thing in Linux distros and sometimes the graphical sound manager does not work when shutting it up. Fortunately there is a simple way to do it in terminal. In Ubuntu (and distros based upon it) type: gksudo gedit /etc/modprobe.d/blacklist In Debian type:

su gedit /etc/modprobe.d/blacklist

And add the [...]

Growing list of schools using Ubuntu

Huy Tran — Thu, 23 Sep 2010 17:33:09 +0000

https://wiki.ubuntu.com/Education/UbuntuSchools

In case you ever doubt that your work is making a difference, just take a look at this growing list of schools using Ubuntu and its derivatives. And an entire project of kids building their own machines to take home and use after completing class – impressive!

Feel free to add other schools and learning projects you know about.