Investigators released video of the May 29 incident on Thursday in an effort to find the pair.
Police say the victim, a 42-year-old man, was seeking shelter from the rain around 10 p.m.
Surveillance video shows the suspects open the door as one of them throws a rock at the man. The two then run away.
At some point they come back and throw more rocks at him, before one retrieves a shopping cart, brings it into the vestibule, and shoves it at the man. The throw more objects at him before leaving again.
However, police say, as the man was curled in the corner suffering from his wounds, the two come back yet again to throw more rocks at him.
The video shows one of them walk right up to the man, and a large rock is visible in his hand.
The victim was treated at the hospital for minor cuts to his head and neck pain. He was listed in stable condition.
Anyone with information is asked to contact Philadelphia Police at 215.686.TIPS (8477) or text a tip to PPD TIP or 773847.