Here's some interesting footage from Syria. According to this report from Al-Masdar News:
Dramatic footage emerged on Friday of a Russian search-and-rescue mission conducted near Palmyra which saved the lives of two Russian pilots who found their aircraft downed by technical failure and subsequently struck by an ISIS missile.
The Russian Ministry of Defence said all Russian military personnel survived the incident and landed safely at the Khmeimim Airbase in Latakia just hours later.
The incident took place near Huwaysis, a village in eastern Homs located on the frontline between the Syrian Arab Army and ISIS.
There's more at the link. Here's the video. Watch it in full-screen mode for best results.
Both helicopters appear to be Mil Mi-24's or Mi-35's (the latter an export version of the Mi-24). From the sounds on the video, I'd say ISIS used an anti-tank guided missile, or perhaps even an unguided rocket like the Russian RPG series, to hit the helicopter once it was down.
I reckon the crew of the helicopter that was forced down were very, very lucky to have another friendly aircraft close enough to pick them up, before ISIS got its hands on them!