The 21-year-old was attacked in Aberdeen in the early hours of Thursday morning.
Grampian Police are looking for a "stocky" Asian man, with short, dark hair and a beard.
Detective Sergeant Lorna Ferguson, who is leading the inquiry, said: "I would urge anyone who recognises this male to contact Grampian Police and pass on his details."
In a separate incident, a woman was assaulted by a man as she walked along a residential street.
The attack happened between 9pm and 9.10pm on Bruce Avenue, Inverness, on Friday. The man was last seen running from Bruce Avenue towards Glenurquhart Road.
Anyone with information is asked to contact police at Burnett Road Police Station, Inverness, on 01463 715555.