According to a US State Department cable, an unknown attacker contacted at least five government officials, including three secretaries of state, a US governor and a member of the US Congress, using an AI version of the voice and writing style of US Secretary of State Marco Rubio. The Washington Post reports.
US authorities do not know who is behind these events, but believe that the perpetrator is likely trying to manipulate influential government officials "for the purpose of gaining access to information or accounts."
The same Signal app, which has already been involved in some high-profile scandals involving the US government, was used for contacts.
The State Department cable says the impostor began his "work" in mid-June 2025 by creating a Signal account using the username "[email protected]." This name is not his real email.
"The actor left voicemails on Signal for at least two targeted individuals and in one instance, sent a text message inviting the individual to communicate on Signal," the dispatch continued. Other employees were also contacted via email.
When asked about the cables by The Washington Post, the State Department said it would "conduct a thorough investigation and continue to take precautions to prevent similar incidents in the future." Officials declined to discuss the content of the messages or the names of the diplomats and officials who were targeted.
The FBI also declined to comment on the Rubio impersonator. Under U.S. law, impersonating a federal officer or employee with the intent to defraud or obtain information is a crime.
Hani Farid, a professor at the University of California, Berkeley, who specializes in digital forensics, said that an operation of this nature does not require a skilled executor, but they are often successful because government officials can be negligent about data security.
"You just need 15 to 20 seconds of audio of the person, which is easy in Marco Rubio’s case. You upload it to any number of services, click a button that says ‘I have permission to use this person’s voice,’ and then you type what you want him to say," says Hani Farid. "Leaving voicemails is particularly effective because it’s not interactive."
"This is why you should not use Signal or other unsecured channels for official government business," the professor added.