5,600 Dutch websites involved in 'biggest hack ever'
The theft of user information from 1.2 billion people which first came to light in August also involved 5,600 Dutch websites, according to the National Cyber Security Centre.
The centre has a list of websites and email addresses ending in .nl which were affected by the hack and a collection of details from other hackers by a Russian gang.
In total, 420,000 websites were affected, 5,600 of which were Dutch.
The owners of the sites are being informed so they can take action where necessary, the cyber security centre said.
Internet service providers are also working with the NCSC to update consumers whose email addresses may have been compromised.
The hack was discovered by US internet security company Hold Security and first reported by the New York Times in August.