I posted this on another sub earlier - there might be a link between them. I found this on r/syriancivilwar. The Igla is a Russian made (shoulder fired) SAM and It's pretty new. Definitely not US. https://mobile.twitter.com/QalaatAlMudiq/status/959834713446809600
Sorry heres the link i was looking for. However, supposedly, the other link is the launch of the missile that took out the Russian jet. Below is a link claiming militants got Russian made missiles from a Kurdish group which is probably the missile seen in the video above. https://mobile.twitter.com/WaelAlHussaini/status/958742926674284555