Some questions about Avast! 4.8 Home

[muis]

Hello to you all,

I'm a new user of Avast! and have a couple of questions concerning scanning of my computer.

First one is that i have noticed that it takes very very long to scan, 5 hours for about 263 GIG of data, whit Avira and AVG this took about 1 to 1.5 hours, why is that?

Second is that some dvd-files packed in a ISO file (not all dvd ISO's) or lose .VOB-files can not be scanned because this is a decompression bomb (i know what a decomp. bomb is but this is false in this case)
Example:
N:\DOWNLOAD\pls-oubb3dvd\pls-oubb3dvd.iso\VIDEO_TS\VTS_02_1.VOB [E] Het bestand is een decompression bom. (42110)
N:\DOWNLOAD\pls-oubb3dvd\pls-oubb3dvd.iso\VIDEO_TS\VTS_02_2.VOB [E] Het bestand is een decompression bom. (42110)
N:\DOWNLOAD\pls-oubb3dvd\pls-oubb3dvd.iso\VIDEO_TS\VTS_02_3.VOB [E] Het bestand is een decompression bom. (42110)
N:\DOWNLOAD\pls-oubb3dvd\pls-oubb3dvd.iso\VIDEO_TS\VTS_02_4.VOB [E] Het bestand is een decompression bom. (42110)

NOTE: This will only occur whit files larger that 1 GIG.

My thoughts are that there could be a virus hidden in a repacked .VOB or ISO witch will be undetected, but strangely it will scan the files if you right click on the folder and choose "scan with Avast!"


Overall I'm am very happy with Avast!, it use way less resources (almost none) than AVG (residentshield) and unlike Avira it has an Webshield and Mailscanner, GOOD SERVICE  

Best regards, Muis

[Lisandro]

First one is that i have noticed that it takes very very long to scan, 5 hours for about 263 GIG of data, whit Avira and AVG this took about 1 to 1.5 hours, why is that?

1. Different sensitivity (archive scanning, etc.) will give you different times.
2. Other programs running in background.
3. avast on-demand speed is not the best feature of avast...

My thoughts are that there could be a virus hidden in a repacked .VOB or ISO witch will be undetected, but strangely it will scan the files if you right click on the folder and choose "scan with Avast!"

I don't think so, I mean, decompression bombs aren't a thing to worry that much.

[muis]

Hello Tech,

Thanks for your replay, i think i get the first answer, but for the second.....I don't worry about the decomp. bomb but i do about the virus that my be whitin the so called bomb, cause Avast! doesn't scan it, it will be undetected.
If there is a virus whitin a .VOB or ISO file, will Avast! detect it when i try to play the file, or will Avast! detect it when i download the file (mostly in Rar format) and why will it scan if i right-click the file and choose "Scan whit Avast!

Manny thanks, Muis

[Lisandro]

If there is a virus whitin a .VOB or ISO file, will Avast! detect it when i try to play the file, or will Avast! detect it when i download the file (mostly in Rar format)

If you set File Shield (v.5) or Standard shield (v.4) to scan on saving, it will be scanned.

and why will it scan if i right-click the file and choose "Scan whit Avast!

It's a thorough scanning, so the file is deepest scanned by this method.

[DavidR]

<snip>
I don't worry about the decomp. bomb but i do about the virus that my be whitin the so called bomb, cause Avast! doesn't scan it, it will be undetected.

Whist a file is within one of these large archives it is inert, so in theory archives don't need to be scanned by an on-demand scan.

If there is a virus whitin a .VOB or ISO file, will Avast! detect it when i try to play the file, or will Avast! detect it when i download the file (mostly in Rar format)
<snip>

Only when the archive is extracted and executables run do they become active and at that point the resident on-access scanner should scan the file. So yes they would be scanned.

The web shield scans 'all' HTTP traffic on port 80 so if you download a zip file, that and its contents should be scanned. Some RARs if they have multiple archive layers may not be fully scanned (though I don't know that for certain), but again archives are by their nature inert and the same principals would apply to what I said earlier.

[muis]

Thanks both for your answers, things are more clear now, thanks for the support.

Best regards, Muis

[DavidR]

You're welcome.