TripAdvisor has become the latest web site this week to admit suffering a customer data breach after a hacker stole part of its member email list, potentially exposing those customers to spam in the future.
In an email to all customers of the travel reviews site, co-founder and chief executive Steve Kaufer explained that all member passwords remain secure.
"This past weekend we discovered that an unauthorised third party had stolen part of TripAdvisor's member email list," he added.
"We've confirmed the source of the vulnerability and shut it down. We're taking this incident very seriously and are actively pursuing the matter with law enforcement."
Kaufer explained that "only a portion of all member email addresses were taken", but he did not elaborate on exactly how many customers are likely to have been affected.
"The reality is that criminals are increasing the volume and sophistication of their attacks. This breach highlights the vital importance of having multiple layers of security that are properly configured," said Russell Poole, security director at consultancy 2e2.
"Security is always high on the agenda of most companies, but the reality is the fight against criminals is getting harder and organisations must ensure they are continually reviewing and improving their security processes, procedures and tools."
The news comes in the same week as online retailer Play.com admitted that a security breach had taken place at a company that handles its marketing communications, with customers already being spammed as a result of having their names and email addresses stolen.
Equinox's Dave Millett explores how phone, mobile and broadband could be affected by a no-deal Brexit
Dust storm on Titan only the third Solar System body where such storms have been observed
New technique could enable quantum computers to scale-up to millions of qubits
Systrom and Krieger taking time off "to explore our curiosity and creativity"