http://youtu.be/X00UcfrglCI
Sounds like it was ZSU-23 and S-60. Probably navigation error that the plane(s) flew so close to Syria. (at that altitude, if it was a recon flight, it may not have been able to gather much in terms of intelligence)
Not this again! The war has been over for 13 years now, and the same old internet themes keep popping up. Let me guess, you also believe NATO lost about 78 planes there too. A very large % of Serbian air defense was, in fact, destroyed. The rest, was kept out of the fight. You don't have to destroy something, to render it ineffective.
Clearly, this has no bearing on Syria, because no NATO planes would be flying low enough, just as in Serbia, to be affected by AAA or short-range SAMs. Long-range SAMs, especially the vast majority of Syria's SAMs which are antiquated, are not likely to be a solution. Large radars and SAM sites emit their position to everyone.
Doesn't this seem a bit "pathetic"? At least try to keep it civilized, instead of gloating over the (hopefully unlikely) loss of two airmen.