https://phys.org/news/2018-07-mystery-bought-websites-implying-senators.html

The Democratic Senatorial Campaign Committee acknowledged to the AP that it had quietly purchased the addresses, which use a new internet suffix "forsale," in March for at least 27 incumbent senators facing re-election this fall and in 2020, without telling the senators. The cybersecurity director for the sergeant-at-arms, the highest-ranking U.S. law enforcement officer in the Senate, has been looking into the matter.

The addresses now controlled by the Democratic political group include the names of mostly Democrats but some prominent Republicans, too. The group masked its role in the purchase to ensure its identity as the buyer remained anonymous. The current price for such addresses, with a privacy guard, is roughly $18 each.