Police say the attack appeared to be unprovoked.
The 25-year-old mother, who spoke to the London Free Press, said the woman was glaring at her and muttering under her breath. When she asked what the problem was, the other woman launched into a verbal assault and spat on her.
The Free Press, which did not name the victim, reported that the she "slapped the attacker with the back of her hand as a natural reflex." In response, the attacker allegedly grabbed the mother's head, dragged her away from her son, pinned her against a wall, and punched her in the face up to three times. Her hijab fell off her head during the attack, she said.