A video from 2014 shows the moment Syrian rebels make a direct hit on a regime tank with an anti tank guided missile (ATGM) which then results in a massive secondary cook off as either the fuel or ammunition are ignited by the blast.

ATGM warheads are specifically designed to defeat heavily armored vehicles. While more modern militaries have developed technology to counter the anti tank weapons; i.e. slat armor, reactive armor, jamming, and active protection... at this point in the war, many of the SAA tanks were outdated relics with no counter measures and easily penetrated by anti tank weapons.