On Wednesday, some of the world's most prominent people, including former President Barack Obama and Democratic presidential candidate Joe Biden, along with Bill Gates, Elon Musk and Warren Buffett, had their Twitter accounts post invitations for an apparent Bitcoin scam. Twitter reacted by blocking further posts from all verified accounts on the service and said it had detected "a coordinated social engineering attack by people who successfully targeted some of our employees with access to internal systems and tools."

The company's explanation has ignited speculation over the identity of the perpetrators and what they were actually targeting in the attack. The scale of the endeavor and its timing -- months before the November U.S. elections -- have prompted some cybersecurity experts to theorize that the attack masked a more nefarious campaign to seize sensitive data.