A man entered Hassans Newsagents on Birkdale Drive, Ashton-on-Ribble, Preston, at 8.50am on Wednesday 10 December, made his way behind the counter and punched the shop assistant several times.
The 66-year-old managed to escape and alerted a passer-by outside before the man ran away empty handed.
The attacker is believed to be a five foot seven teenager. He was wearing red gloves, blue jeans, a blue thigh length jacket with red trim and stripes on the hood and he was carrying a ladies style handbag with some sort of animal print on it.
DC Nicola Barnes of Preston CID said: “This was an unpleasant incident for the victim who suffered a nasty black eye.
“We are keen to try and identify the man in the CCTV images and anyone with information should contact us on 101 quoting log number 0206 of December 10th.”