The Canadian branch of Telecomix—a loose-knit hacktivist group that supports open access to the Internet and digital rights—has taken credit for cracking into one of Mr. Trump's websites and publishing a tribute to television host Jon Stewart on the eve of his last broadcast with The Daily Show.

A message from the loose-knit hacking group appeared on Trump.com early Monday and had managed to stay online so far for several hours without being removed.

"Mr Stewart, we at @TelecomixCanada would like to take this opportunity to thank you for the many happy years of quality journalism and entertainment you and your team have undertaken at Comedy Central," reads part of the posting, which is by-and-large more of a celebratory essay praising The Daily Show host than a jab at The Donald.