Who Leaked The Classified Pentagon Documents? From Video Game Forum To 4Chan

The U.S. is now investigating the leak of highly classified Pentagon materials less than a week after the documents, ranging from briefing slides and assessments of international support for Ukraine, were published on online social media platforms.

To date, little is known about who may have been behind the leak. However, the investigation has cast a spotlight on users of the online platform Discord. The documents first surfaced on the platform, initially being shared among members of a tiny group until it was reposted by another user to another group last month and eventually to a server called "Minecraft Earth Map," per Bellingcat.

From there, the leaked Pentagon documents spread through pro-Russian Telegram channels and on 4chan, which is a series of wholly anonymous, anything-goes forums. A user posted a series of eight messages, three of which had images that showed some of the leaked documents.

Discord launched its platform in 2015 with the aim of giving videogamers an easier way to communicate while playing online games. Discord users can chat about games and other topics in invitation-only groups referred to as servers.

However, the platform has since been embroiled in controversy, including being used to share child pornography and playing a role in the 2017 "Unite the Right" rally in Charlottesville when the leader of a white supremacist group promoted neo-Nazi ideology on the platform. The rally left at least one person dead.

It is unclear how the leaks will impact the U.S. and its allies. The documents contained classified information about foreign countries, including Ukraine which Washington warned could face a "completely reduced" supply of medium-range air defense capabilities next month.

One page of the leaked documents also claimed that Russian officials — particularly Russian National Security Council Secretary Nikolay Patrushev and Russian Chief of the General Staff Valeriy Gerasimov — planned to sabotage the war in Ukraine when President Vladimir Putin undergoes his chemotherapy.

The U.S. government is now coordinating an interagency probe with the Pentagon's Office of Intelligence and Security to determine the source of the leak and examine whether any sources and methods have been compromised after the documents were posted online, per CNN, citing three U.S. officials.