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Consumer Products => Avast Free Antivirus / Premium Security (legacy Pro Antivirus, Internet Security, Premier) => Topic started by: irj on January 23, 2010, 02:26:49 AM

Title: Scanning in different ways and arriving in different results.
Post by: irj on January 23, 2010, 02:26:49 AM
I don't know if it is a bug. I putted 4 eicar zip files in one folder of my flash drive and scanned it in 4 different ways.

Firstly, right clicking the drive letter of my flash drive in my computer. It was good. It detected the 4 infected files. So no issue with this one.

Secondly, I used "Removable media scan" in avast user interface. Scan completed but there were some files could not be scanned. When I clicked the "show results", it was my dvdrom drive so nothing to worry about it since no cd/dvd inserted to my dvdrom drive. But it didn't found the eicar zip files. I also noticed that the amount of data tested was less than the amount when scanned it using the right clicking the drive. Going back to the dvdrom drive, better if the avast will not anymore alert the user about some files could not be scanned in case of empty dvdrom drive. It makes the user confuse.

Thirdly, I scanned it using "Select folder to scan". I checked the drive letter of my flash drive and nothing found. The amount of data tested was similar to my second method.

Lastly, I also scanned it using "Select folder to scan". I checked the folder where the 4 eicar zip files located and again, it did not found.

I did not change any settings in avast user interface.

The "removable media scan" is very helpful to people who need to scan 4 or more removable drives like me. In my opinion, the 4 methods I showed should arrived in detecting the 4 eicar zip files. So I am worried to the results I got.  :-\

I am currently using the avast! free antivirus.
Title: Re: Scanning in different ways and arriving in different results.
Post by: DavidR on January 23, 2010, 02:46:47 AM
It would entirely depend on what Scan Settings, Packers list is set to if the zip archive isn't ticked it won't get scanned. There are different settings for different scans and the defaults will have different settings probably.

Title: Re: Scanning in different ways and arriving in different results.
Post by: irj on January 23, 2010, 03:16:36 AM
Thanks DavidR for your reply. As I looked for the Scan Settings, only the "Select folder to scan" has it. How about the "Removable media scan"? Do am right, the flash drive, MMC, SD are part of removable media? Is it not harmful to my system if the virus/malware inside the zip file?

I am new in avast and sorry for my ignorance with regards to this issue.
Title: Re: Scanning in different ways and arriving in different results.
Post by: DavidR on January 23, 2010, 04:11:44 AM
Archive files, .zip, etc. are inert, you need to extract the files and then you have to run them to be a threat. Long before that happens avast's File System Shield should have scanned them and before an executable is run that is scanned.

I'm not exactly sure if SD MMC are considered removable medial by avast, for me in avast 4.8 I always considered it to be CDs, DVDs and Floppy disks. Now there is much removable storage (USB, SD, MMC, etc.) it is hard to say how they are classified as when plugged in they seem to be treated by windows as removable storage and assigned a drive letter.

So if plugged in when you run a Full System Scan then I think they would be scanned.
Title: Re: Scanning in different ways and arriving in different results.
Post by: irj on January 23, 2010, 03:04:22 PM
DavidR thank you for the information and for your time. It is already clear to me and now I know that I should not worried about how avast scanned the files. I learn something new today. Thank you again.  :)
Title: Re: Scanning in different ways and arriving in different results.
Post by: DavidR on January 23, 2010, 04:39:18 PM
No problem, glad I could help.