Author Topic: Virus removal - How is it done?  (Read 4867 times)

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Offline TimN

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Virus removal - How is it done?
« on: September 06, 2003, 12:29:14 PM »
I recommended Avast to a friend and after installing she asked me a question baout virus removal I couldn't answer.  That's why I'm here.  :)

Avast creates the Virus Recovery Database (VRDB) every now and again althoughI'm not sure how often. How often is this and does Avast solely rely on this database for removing viruses from infected files?

In other words if a file was infected by a virus before the VRDB had been formed would it be possible to clean the file of the virus? In fact what methods does Avast use to clean viruses out of infected files or is the only option to delete them or put in the virus chest?

Offline igor

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Re:Virus removal - How is it done?
« Reply #1 on: September 06, 2003, 12:58:16 PM »
By default, VRBD is updated every 3 weeks; the interval can be changed by editting avast4.ini file, though.

avast! mostly relies on VRDB, yes - at least considering the "executable files" (the macroviruses are cleaned by other methods, not using VRDB). So, cleaning an infected file right after you installed avast! (i.e. without having the original file in VRDB) would not work.

avast 4.1 will include our Cleaner - that is able to clean the most common viruses using a virus-specific methods. The number of viruses healed by Cleaner will grow in time, as well as the integration of the Cleaner into avast! will get tighter.

Note, however, that any generic virus removal methods (that do not use a VRBD-like database) is usually not able to turn infected files exactly into their original state. For example, some information in the file header is often irreversibly overwritten when an exe-infection occurs. This information is unimportant in most of the cases; sometimes, however, it may cause problems - WinZip self-extracting archives will announce CRC errors, some copy-protected programs may not run, etc.

Offline TimN

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Re:Virus removal - How is it done?
« Reply #2 on: September 06, 2003, 01:20:40 PM »
Thanks,
I went to edit the avast4.ini to have make the VRDB update more frequently but strangely the very last line of the ini file was missing.  There was no "runinterval=10080" or wahetever number it should have been.

I checked and the last update to the VRDB was done 18 days ago so it was working. I added the line "runinterval=2880" as I want it to run every 2 days and resaved the .ini file.  Is this OK? Why was the line missing?

Obviously it will depend on how much stuff is on my PC but how long does it take to update the VRDB when my computer is idle?

Offline igor

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Re:Virus removal - How is it done?
« Reply #3 on: September 06, 2003, 01:49:28 PM »
When no RunInterval value is in the avast4.ini file, the default (3 weeks) is used.
I'm afraid I don't know how long the VRBD generation can take... of course, it depends on how much files you have on your drives... I think it shouldn't take very long (an hour?) - but I really don't know, I may be completely wrong.

As for shortening the interval of VRBD generation - it may not be the best idea; please read my old post here.
(why can't the Search command find this post  ???)

Offline raman

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Re:Virus removal - How is it done?
« Reply #4 on: September 06, 2003, 01:57:00 PM »
Mybe because th boardsearch searches only 60 days with standard settings?
MfG Ralf

Offline igor

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Re:Virus removal - How is it done?
« Reply #5 on: September 06, 2003, 02:08:56 PM »
Shame on me... I didn't notice the limit  :-[