On the 2nd day of Russian bombings they targeted Ahrar al-Sham, the main component of the Islamic Front who are fighting ISIS. Granted, though, that the Islamic Front is a Sunni Islamist group that wants to overthrow Assad, create an Islamic state, and have Sharia law under a Majlis-ash-Shura (think Iran's Supreme Council, just Sunni instead of Shia). Also according to opposition news sources the Russians did bomb the town of Al Shedadi which is in ISIL controlled territory.
"The new round of strikes on Thursday — conducted with two models of Soviet-era warplanes, the Su-25 Frogfoot and Su-24 Fencer — was said by Mayadeen, a pro-Damascus news channel, to target the Army of Conquest, a coalition of insurgent groups that includes the Al Qaeda-affiliated Nusra Front, the hard-line Islamist group Ahrar al-Sham and a range of less extreme Islamist groups — all of which are opposed to the Islamic State.
Russian officials nonetheless insisted that they had hit four “objects of the Islamic State” in the provinces of Idlib, Hama and Homs. The Islamic State is most active in areas significantly to the east of those regions. Russia, like Mr. Assad, has tended to make little distinction among the many insurgent groups in Syria’s four-year-old civil war."
This is going to be interesting for Russia. Their Muslim population is largely Sunni and from the North Caucus region (Chechens, Ingush, Kabardin, Karachay, and Dagestani), and also from the Volga basin ( Tatars and Bashkirs) while they're siding with the Shias in Syria. Only 5% of the Russian Muslim population is Shia.