The actual source of the information may never really be known. Recent data breaches have exposed a large amount of information that is available for purchase on the dark web. Bad actors are filing these claims by buying identities online, taking advantage of prior data breaches, network intrusions, email phishing or cold calling using an impersonation scheme to get personal information.
Be careful in sharing information or asking for assistance through social media. Fraudsters will look for bits of information on social media in order to put together enough information to file a claim using your identity.