The victim, who is in her 40s, was on Victoria Road at 11.15am on Friday October 2 when a man grabbed her and pushed her against a wall.
The suspect is described as a young white man, about 5ft 9ins tall, with short hair. He was wearing a grey hoodie and had a backpack.
Anyone with information that might help with the police's investigation - including any CCTV, dash-cam or doorbell-camera footage - is asked to email [email protected], quoting reference number 12200173044.
They can also call North Yorkshire Police on 101, select option two, and ask for Michael Ward.
Information can be passed on anonymously via Crimestoppers on 0800 555111.