Introduction to LiveCD contd.....

Hello visitors,

In my previous post I gave a brief idea about what actually a LiveCD(RescueCD) is and purpose of using them. Now I will provide some extra features a RescueCD provides. It varies from company to company that provides a RescueCD distribution. I am going to give a short tutorial regarding using a RescueCD. I choose Dr.Web LiveCD and AVG RescueCD (I prefer these two as the best options for post infection scenarios) 

Dr. Web LiveCD

It is a software product based on Dr.Web antivirus scanner. It allows to restore the system when loading the system from the hard drive becomes impossible due to virus infection. It is distributed as boot disk and is based on portable linux operating system(Gentoo Linux) and also inbuilt software(OnDemand scanner) intended for scanning, curing, deleting files from the target directory/drive.

System Requirements :

• i386 processor(P4,dual core....etc)
• Minimum of 256MB of RAM
• CD/DVD drive

Download the liveCD from the link provided above, its size is approx 173MB, the downloaded file will have .iso as an extension so it can be burned directly into CD with help of any traditional CD/DVD burning software(links provided in the previous post). After burning the disk becomes a bootable disk and also do make sure that your system is set to boot from CD/DVD drive(goto BIOS setting and change the boot priority to your CD/DVD drive)

When the cd is inserted in the CD/DVD drive and system is rebooted again

 Dr.Web liveCD provides four options :

1. Standard mode(the first option) : Load all the necessary modules with easy to understand interface.
2. Advanced mode : Its is recommended only for exp users who are familiar with Unix based commands and so I would not recommend for first time users.
3. Start Local HDD : It will load from your hard drive i.e as our system normally boots.
4. Testing Memory : When your computer is unstable and restarts at random.

After selecting the default load option the liveCD will load essential modules to setup a miniOS and finally will look as shown below :

Linux based environment

It contains following basic applications :

• Dr.Web Scanner for linux
• Firefox browser
• Sylpheed mail client
• Midnight commander file manager
• command-line terminal
• Leafpad text editor

Basically it is just your miniOS which directly runs in RAM, The main advantage of having a miniOS is when your computer is highly infected and you won't be able to restore your system in such situations formatting your system is only the option, so this miniOS helps you to obtain copy of important files which gets deleted during formatting process.

Dr.Web Scanner in the linux environment

It is necessary(not compulsory) to have an internet connections so that Dr.Web has the latest viruses definitions. With the help of the scanner you can select the target directory/drive in your system which you wish it to be scanned. Wait for the scan to be completed and it will show you the final result whether a virus(es) is/are found or not. If found you will get an option of curing/deleting/quarantine/renaming.

Advantages for using Dr.Web LiveCD

• Good file curing capability.
• Small updates(but still can detect thousands of viruses)
• Has a dedicated Linux environment for backup purposes.

Disadvantages

• Slow scanner(can even be slower when scanned in highly infected system)
• Virus detection is not that high but not low also.

AVG RescueCD

AVG is another company that provides antivirus solutions, its quite a known among the users as compared to Dr.Web and other solution that I named in my previous post. It provides a RescueCD that can be downloaded over here (click on the 1st download link which will download the .iso file) the file size is approx 94MB.

System Requirements :

• Intel Pentium or equivalent processor (300Mhz)
• 512Mb of RAM
• CD/DVD drive

When computer is booted with AVG RescueCD inserted the welcome screen starts(after some initial loadings of modules)

Welcome screen of RescueCD

During booting the AVG RescueCD will mount all hard drives of your computer. This will make them available for scanning and editing. In most of the cases select the first option while rest of the two option are normally required when system has less resources.

Typical UI of AVG RescueCD

It is recommended that user first update to latest virus definitions. If the user does not have the internet connection she/he can copy the updates to the USB and can manually update the definitions(tutorial will be provided later)

After the update is completed perform the scan, the scan can be performed either on the directory/drive. After scan is completed the result(if infections are found) will be shown as below :

Option for directory/drive scan

When infected file is found

File handling

You can select relevant option on how to handle the file. And after the file is been deleted/renamed the system can be rebooted.

NOTE : In case of AVG RescueCD it doesn't provide a dedicated portable miniOS like that of Dr.Web so retrieving important files from your infected system is bit difficult for normal user. So I don't recommend it for user who are looking for data retrieval purposes unless they are quite familiar with the RescueCD. 

For manual Update

Download the virus definitions file from here and copy the files in USB. Now from the main UI of AVG select on Update----> Select Offline----> browse through the directory where the file(with .bin extension is stored)

Advantages :

• Faster Scans
• Offline update possible
• Good detection rate

Disadvantages :

• Difficult to maneuver if user is not familiar with keyboards
• Backing up of files may sometimes be tedious
• Requires system to have atleast 512MB of RAM if not then system might not respond properly

Thats all for now, hope you all might have liked my brief tutorial regarding working with LiveCDs and found helpful to you :)

Take care visitors


regards,
Ishan ;)