A hack has compromised TeleMessage, a messaging platform used by former National Security Adviser Mike Waltz and other US government officials, raising concerns over the potential leak of sensitive data. The platform, which mimics Signal while adding archiving features, is used by government agencies to comply with records retention requirements. 

The hacker, who exploited a security flaw, accessed archived communications from several users, including data linked to government bodies like Customs and Border Protection, as well as private companies such as Coinbase. 

Despite not accessing Waltz's messages, the breach revealed usernames, passwords, backend access, and chat snippets. The hacker claimed the intrusion took only 15-20 minutes and said they did not report the vulnerability to TeleMessage. The breach also exposed chats from modified versions of other apps like WhatsApp and Telegram. Signal distanced itself from the cloned app, emphasizing that it cannot guarantee the security of unofficial versions. The incident has raised concerns about the security of archive-enabled messaging apps used in government settings.