Earth Hour March 28th 0830-0930

Switch off the lights for one hour from 0830-0930.

Its time for us to act and reflect upon. Global Warming vs Earth.

Reset the root password on a linux box

Intro
The following steps were used to successfully reset the root password of a "Fedora 10" machine. In general, can be applied to any linux machine.

1. GRUBWhile booting, after the initial splash and POST screen of the bios, the control transfers to GRUB. If there is just one linux operating system installed, the GRUB screen is bypassed to the booting screen, in that case just keep on pressing or tapping the ESC Button until you see the GRUB Menu.
   
2. Edit Choose the OS you want to boot into and press "e" to edit.
   
3. Edit Find the line that corresponds to kernel, and again press "e". Add the following line to the end of the line.

   single init=/bin/bash

   
   Then press enter, and then "b" to boot the OS. After booting you will get a root shell.


4. Mounting the filesystem in readwrite mode: Type in the following command to remount the filesystem in read write mode.

   mount -o remount,rw / 


Not doing this step might give the following error when running passwd, passwd: Authentication token lock busy.

5. passwd Next just use the passwd command, and give a new root password, Now that's simple.


6. Reboot or init 5

That's really all I did.

OR from the root shell, you can also edit the /etc/shadow file to remove the password.
OR copy the /etc/shadow /etc/passwd file and use John-The-Ripper software to try cracking the password.

Stuck? Let me know...

              .___.__       .__  __         .__        ___.    __    
            __| _/|__| ____ |__|/  |______  |  | ______\_ |__ |  | __
           / __ | |  |/ ___\|  \   __\__  \ |  | \____ \| __ \|  |/ /
          / /_/ | |  / /_/  >  ||  |  / __ \|  |_|  |_> > \_\ \    < 
          \____ | |__\___  /|__||__| (____  /____/   __/|___  /__|_ \
               \/   /_____/               \/     |__|       \/     \/
                                
              a8888b.   
             d888888b. 
             8P"YP"Y88 
             8|o||o|88                
             8'    .88 
             8`._.' Y8.                      
            d/      `8b. 
           dP   .    Y8b. 
          d8:'  "  `::88b 
         d8"         'Y88b                                   
        :8P    '      :888                            
         8a.   :     _a88P                              
       ._/"Yaa_:   .| 88P| 
  jgs  \    YP"    `| 8P  `.
  a:f  /     \.___.d|    .' 
       `--..__)8888P`._.' 

csrcs.exe Virus Manual Removal Steps

csrcs.exe

Don't confuse csrcs.exe with csrss.exe, csrss.exe is a legitimate windows service, whereas the csrcs.exe is a Trojan, or a virus. It resides in the

C:\Windows\System32\

folder.

To remove csrcs.exe and all its effects, first take

regedit

( Start > Run : regedit ). Then search for the string "csrcs.exe", and remove all occurrence of the string from the values. If there is a path given like "C:\Windows\System32\csrcs.exe" delete the entire value from the registry.

Next delete the file, from C:\Windows\System32.
If you do not find it, first show all hidden files. You may have to fix that in the registry to show hidden files. This has been covered in an earlier post. So once thats done delete the exe file.

Restart.
Hope that does it.
If not do comment,
I will get back to you ....

Edge Detection on Images

Intro
The following images show the result of applying various edge detection algorithms on this image.

Original Image

1. Prewitt
   
   

   -1 -1 -1
   0 0 0
   1 1 1

   
   
2. Sobel
   
   

   -1 -2 -1
   0 0 0
   1 2 1

   
   
3. Laplacian 1
   
   

   -1 -1 -1
   -1 8 -1
   -1 -1 -1

   
   
4. Laplacian 2
   
   

   0 -1 0
   -1 4 -1
   0 -1 0

   
   
5. Stochastic
   
   

   0.802 0.836 0 -0.836 -0.802
   0.845 0.897 0 -0.897 -0.845
   0.870 1.000 0 -1.000 -0.870
   0.845 0.897 0 -0.897 -0.845
   0.802 0.836 0 -0.836 -0.802
   

   
   

ARP Spoofing or IP Masquerade

What is IP Masquerade or ARP Spoofing?

In order to understand, What IP Masquerading or ARP Spoofing is we need to look into the working of the Ethernet. Ethernet is a Data Link Layer protocol, which uses MAC addresses embedded in the network interface cards (NICs) to communicate between devices. But the network layer and the above layer communicates using IP addresses. So in order to communicate, there must be some mechanism to map the IP addresses in network layer to the MAC addresses in the data link layer. This is accomplished using the ARP (Address Resolution Protocol). In this method when a packet needs to be sent to a destination machine, given its IP, the ARP protocol is used to send an ARP Request. This request is broadcast among the machines on the ethernet. If the machine is within the same ethernet, the MAC address of the corresponding machine is obtained from the machine as an ARP reply. This MAC address is cached by the machine, in an ARP Table and further packets to that IP is send to the machine with the MAC address.

Now the inherent flaw in the protocol is that, there is no mechanism to verify that the IP address corresponds to the MAC address and a forged ARP reply updates the ARP cache. So if a forged reply comes for an IP address and MAC pair, the ARP table gets updated. No questions asked.

Thus any machine in the network can act as if its another machine and hijack all the information flowing. This is called ARP spoofing or IP Masquerading.