A woman was assaulted as she walked home after a night out in Glossop.
The 24-year-old victim was walking along Simmondley Lane when the attack took place.
A man tried to grab the victim from behind but she freed herself and punched her attacker to the jaw before running off.
The incident happened at about 1.45am on Sunday, November 9.
The brief description of the offender is that he was about 5ft 11ins, wearing a dark hooded top and possibly a scarf covering part of his face.
Police investigating the offence want to hear from anyone with information or who may know a man with an injured jaw.
Witnesses or anyone who can help officers with their inquiries should call Derbyshire police on 101, quoting crime reference 47520/14.
You can also call Crimestoppers, anonymously, on 0800 555 111.