Submit the file to virus@avast.com (in password protected archive or through avast chest) I don't know exactly what type is this malware. But as you said; is possible that the trojan is a "Downloader" type. the generic nature of this detection means that the Payloads performed by this group of trojans may be highly variable, and therefore difficult to describe specifically. This group of trojans has been observed to perform any, or all, of the following actions:
* redirect Web traffic
* manipulate certain Windows or third-party applications including settings or configurations
* drop or install additional malicious programs
* download and run additional malicious programs