A data breach on adulterers’ social network Ashley Madison has exposed the personal data of some of its 37 million users, the blog Krebs on Security reported Monday. An individual or group of hackers called “The Impact Team” posted a sample of the leaked data, which has since been taken down. The hackers have threatened to publish more personal information unless parent company Avid Life Media, which owns the social network, permanently takes down Ashley Madison and the hookup site Established Men. The hackers accused ALM of keeping user information even after a $19 service promises to delete full profiles. ALM Chief Executive Noel Biderman confirmed the hack and said the company believes someone who had inside access is behind the attack.