The Mossad reference is symptomatic of the "ops" floating around on social media—Iran has repeatedly suggested ISIS is a confection of MI6 and the CIA, sometimes with the help of Mossad. There was a major online hoax claiming documents leaked by Snowden showed al-Baghdadi had been trained by Mossad, which seems to have been entirely debunked.
What we know with some degree of certainty is that Iran is aligned with Assad in Syria and with Russia, and that Britain, the US, Israel and Turkey are lined up against them.
We know the CIA has funded Syrian "moderates" who have at least at one stage had a lot of overlap with fundamentalist Islamic groups ISIS and Jabhat al-Nusra, and that the best case from the standpoint of an apologist for US policy is that the CIA has been quite unsuccessful in stopping US materiel from getting into fundamentalist hands on a regular basis.
Since the CIA has been openly pursuing regime change in Syria, it has also sponsored ops on social media to increase the global profile of the Free Syrian Army, a fairly dubious entity made up of at least thirty independent "moderate rebel" groups.
In real terms, the shift that we're seeing now is that the US has previously been content to create mayhem in Syria and to indirectly arm fundamentalist groups while there was a prospect of forcing Syrian regime change.
US ally Turkey has been conducting an "anti ISIS" campaign that actually consists in significant part of attacking Kurdish targets. Turkey has also destroyed infrastructure for essential services such as electricity and water in cities in Turkish Kurdistan, putting Kurdish people there in dire straits.
US ally Israel has been put in the strange position of an almost-alliance of convenience with the salafist groups against Shiite organisation Hezbollah and its ally Hamas in Gaza and the West Bank.
Since Russia entered the conflict by having Assad "invite" it to bomb ISIS and Jabhat al-Nusra targets, it has also been attacking positions held by US-backed forces. Note that there is still a huge grey area as to which groups are fundamentalist terrorists, and which are "moderate" rebels suitable for inclusion in a conceptualised political regime transition under US guidance.
Like all campaigns of bombardment, this Russian aerial campaign has been killing relatively large numbers of civilians as well as striking military targets.
The current US shift is away from support for the FSA and towards at least a temporary reprieve for Assad as the US and Russia turn to waging a joint campaign of sorts against ISIS. As this takes place, you can expect different rhetoric from Iran focused on legitimising Assad's control of Syria and praising the Russian campaign against ISIS and al-Nusra.
I've heard it alleged that accomplishing a political partition of Iraq along sectarian lines remains a long term US goal, as does diminishing the influence of Iran.
