Boot virus detected on partial disk image, false positive?

1234ava · 2015-04-27T13:13:23.000Z

Avast Free detected WXY-B boot virus on a Macrium Reflect image file of mine. I suspect a false positive though.
I gather WXY-B infects the mbr and the 1st partition boot sector, but there was no 1st partition in my image. It wasn’t a full disk image: it had just the disk’s mbr and two final partitions, including an unformatted partition. See screenshot below, the imaged partitions are on the far right hand side.

https://forum.avast.com/index.php?action=dlattach;topic=170185.0;attach=161240;image

Besides, other Reflect images I created on the very same day, containing the same disk mbr but some other partitions on it, were NOT detected as infected with WXY-B.

Pondus · 2015-04-27T13:33:51.000Z

have you tested file at www.virustotal.com ? … if tested before, click rescan for a fresh result
post link to scan result here

1234ava · 2015-04-27T14:20:29.000Z

It’s a disk image file sized over 1 GB, so I cannot upload it to VirusTotal.

Pondus · 2015-04-27T14:29:38.000Z

report it here https://support.avast.com → avast virus lab and you will get instructions how to send it to the lab so they can check it

1234ava · 2015-04-27T18:00:43.000Z

Done, thanks!

1234ava · 2015-05-06T16:49:47.000Z

Avast Virus team examined my disk image file and confirmed it is safe, no boot virus, just like I thought.

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