One in five thwarted identity theft attempts last year was aimed at young professionals living in rented accommodation, according to a credit checking company.
Experian said 20% of detected and prevented ID theft attempts in 2015 were aimed at young professional renters, meaning this group is bearing the biggest brunt of a surge in identity theft.
People in this sector were the target for nearly a quarter (23.4%) of all attacks involving current accounts, which was the biggest focus for fraudsters in 2015.
Experian said that while London remains the "fraud capital" of the country, the inner cities of Birmingham, Leeds, Manchester and Glasgow have also been particularly vulnerable.
It said the high density of professional renters in shared blocks of flats contributes to this, with personal details easily accessible in shared mail boxes.
Isolated pockets of fraud hotspots have also been detected in the Highlands, Wales, Devon, Cornwall and Hampshire, Experian said.
The figures also show that affluent families living in prestigious areas, who tend to have high assets and investments, became less of a target for identity fraud attempts, accounting for 8.3% of the total in 2015, down from 10.7% in 2014.
Nick Mothershaw, UK and Ireland director of identity and fraud at Experian, said: "Easily accessible, shared hallways can offer opportunities for those wanting to harvest personal details and these figures highlight the need for renters to be vigilant.
"People in these shared blocks must remain aware of their finances and spot any irregularities that could be a sign of fraudulent activity."
The figures are taken from UK fraud prevention system National Hunter, which Experian operates on behalf of its members.
The system enables financial firms to cross-match applications against more than 100 million previous application records to spot signs of fraud.
Experian said that to prevent themselves falling victim to identity fraud, people should always shred personal documents and never respond to cold calls or emails asking for account details, Pins, passwords or personal information.
It also warned people not to give too much away on networking websites. For example, pets' names or children's names could be used as passwords.
It is also important for people to register to vote at their current address as otherwise thieves could use previous address details to open new credit accounts, and run up debts in the previous occupant's name.