Bootable Antivirus CD
Boot and Disinfect CDs
One of the great advantages of booting to a cd to clean up a virus infected system is that the cd is more likely to get everything. In a running live operating system, it’s hard to say how many viruses might be running hidden, or may interfere with a virus scan, but booting to a linux live cd or other cd that can do a virus scan can be a good way to make sure that nothing interferes with your virus removal. The big disadvantage to this kind of scan is that if important system files are infected they may be quarantined and it may prevent the system from booting. One example is a virus in an Outlook PST file. A virus scanner in windows would be able to interface with Outlook and remove the message that the virus is attached to. A boot cd for the same purpose would quarantine the enitre pst file for you to deal with at a later time. It’s a tradeoff.
At one point in time I had my own livecd that I developed for virus removal. It was based on Mandrake and had clamav on it. When the system booted it attempted to check for antivirus updates and then started straight into it’s virus scan. It was fairly successful for me, but the tradeoffs above had me move it lower in my list of priorities.
f-secure has a rescue CD that is linux based and does exactly this same thing. It will boot, check for antivirus updates and then proceed to a scan. They are very up front as to the risk that if a system file is infected it may render the system unbootable. Of course, a repair reinstall should fix things assuming that it’s not too badly damaged. I’ve tried it and used it after running several other fairly thorough scans and like having this option as a second opinion that can work outside of the infected systems operating system.