Here’s a video documenting the evolution of Syrian Army tanks during the several-year civil war, which include both improvised “DIY” type modifications as well as technological upgrades organically-developed and received from allies.
Susceptibility to rocket propelled grenades and recoilless rifle rounds quickly forced Syrian troops to develop improvised countermeasures to increase survivability. They piled sandbags on top of the armor, and hung chains and welded steel cages around the hull of their tanks. The idea was to detonate shape-charged warheads prematurely to exhaust their spalling distance before actually reaching the vehicle’s hull.
Later, when the rebels began receiving anti tank guided missiles (ATGM) like the BGM-71 TOW through President Obama’s arm and equip program, the improvised armor systems were of little use. Soon, the Syrian military began developing active protection systems like the Sarab variants that use infrared lights to mitigate the threats of enemy missiles.