The 41 year-old woman was getting into her car outside the Community Resource Centre in Victoria Road, Bridlington, between 8.45pm and 9pm on Monday (September 4), when she was approached from the side by her assailant, who tried to steal her bag.
She shouted for help, at which point her attacker fled towards Wellington Road.
The assailant is described as around 18, white, 5ft10ins tall, with a pale complexion, a dark fringe, and dirty, bitten fingernails.
Anybody with any information on the attack should contact Bridlington Police on 0845 60 60 222, quoting log number 752 of September 4.