The victim, a woman in her 50s, was attacked by another woman in the incident on Bridge Street in the centre of Tadcaster at around 2am on Sunday, May 19.
The assault left her with a fractured wrist and scratches.
A 23-year-old woman has since been arrested in connection with the assault and released on conditional bail.
Now North Yorkshire Police are looking for a good Samaritan who was passing when she stopped to come to the victim's aid.
If you are the woman who helped or have any information that could assist the investigation should contact North Yorkshire Police on 101, select option 2, and ask for Katie Swift, or collar number 6-4-3-7. You can also email [email protected]
If you wish to remain anonymous, you can pass information to Crimestoppers on 0800 555 111.
Please quote the North Yorkshire Police reference number 12190089825.