No, the site convertonmp3.com is not hacked. It is distributing malware by design. That is the business model of this and many other similar sites.
At the above link, you get a “Download with ConvertOnMP3.com Download Manager” checkbox which is ticked by default. (This did not appear for me until I browsed with a Windows web browser; YMMV.) If you click the download link without unticking the box then instead of the .mp3 you get a .exe file. That is the file virustotal is complaining about (note the filename is listed as “The_Supermen_Lovers_feat_Mani_Hoffman_Starlight_Official_Video.mp3.exe”.
The executable is a downloader from the pay-per-install programme at installpath.com (related domains: keenondownload.com, leadingdownload.com), which will then install a selection of adware depending on whoever is paying them at the time.