The details of three individuals were publicly displayed in Chapel Road in Dungiven on Thursday evening.
PSNI Assistant Constable Chris Todd said those named were serving police officers.
Last month, the names of 10,000 officers and civilian staff were mistakenly released in a Freedom of Information request.
ACC Todd said he recognised the impact on the individuals and their families following Thursday’s incident.
He said the police had been in contact with them and that the “safety and welfare of all our officers and staff remains our priority”.
Additional security and patrols had been implemented across Northern Ireland as part of the police response, the senior officer added.
SDLP East Derry MLA Cara Hunter said police officers must be able to serve their communities free from intimidation.
She was speaking after personal details relating to police officers appeared in the Dungiven area on Thursday.
Said the East Derry MLA: “Following the PSNI’s major data breach many officers and their families are living in fear that their personal details may be exposed to the public.
“Given the sensitive nature of policing here it’s imperative that officers feel as safe as possible in their homes and in their communities and it’s disgraceful that anyone would try to exploit this to intimidate or to put officers in real danger.
“I’m deeply disappointed that details relating to officers have been posted in the Dungiven area and I welcome their swift removal.
“Those who seek to intimidate or threaten police have no support from the local community here and any attempt to use information about police officers in this way should be fully condemned and rejected.”
SDLP Policing Board member Mark H Durkan said: “While it was inevitable that a small number of people would seek to use the information leaked through the data breach in this way, we cannot underestimate the harmful impact this is having on officers and their families.
“Thankfully there have been relatively few incidents of this nature since the leak, but our police officers now must live with the knowledge that it could happen every single day.
“We cannot immediately repair the harm that has been caused to police officers, staff and public confidence in policing, but it’s important that we the investigation into the breach results in outcomes that ensures this never happens again.
“Anyone using information about police officers in this way must be dealt with in the strongest possible terms and I’d urge those with information to come forward to police.”Tags: