If avast didn't detect this:
Send the sample to email@example.com zipped and password protected with the password in email body, a link to this topic might help and undetected malware in the subject.
Or you can also add the file to the User Files (File, Add) section of the avast chest (if it isn't already there) where it can do no harm and send it from there (select the file, right click, email to Alwil Software). No need to zip and PW protect when the sample is sent from chest. A copy of the file/s will remain in the original location, so any further action you take can remove that.