US secretary of defence Pete Hegseth used a commercial internet line—known in IT terms as a “dirty line”—installed in his Pentagon office to bypass standard defence department security systems and access encrypted messaging platforms like Signal from a personal computer, source told news agency Associated Press.
The “dirty line” was specifically used to access websites and applications blocked on the Pentagon’s usual networks: SiprNet (for classified data) and NiprNet (for unclassified but secure communication), reported ABC news. Pentagon rules prohibit any unauthorised electronic devices in the defence secretary’s office due to the risk of spyware and hacking.

Earlier this week, reports revealed that Hegseth shared sensitive details about military air strikes in Yemen with close personal contacts through a private Signal group. The group, created by him in January before his confirmation, included his wife Jennifer (a former Fox News producer), his brother Phil, and lawyer Tim Parlatore, who also advises him at the Pentagon. The Times said Hegseth shared information such as flight timings of F/A-18 Hornets targeting Houthi rebels on March 15.
This was the second such case involving Hegseth. Last month, The Atlantic revealed that its editor-in-chief had accidentally been added to another Signal chat about the same Yemen operation.
Back in 2016, Hegseth had criticised Hillary Clinton on Fox News for using a private email server during her tenure as secretary of State, calling it a “fireable” and “criminal” offence for anyone with a top secret clearance.