ONE News has gained access to the personal files of American soldiers, uncovering military secrets from the most powerful nation in the world.
In November last year the US Defence Department banned the use of portable data storage devices.
However, Chris Ogle from Whangerei got more than he bargained for when he bought an MP3 player from an Oklahoma thrift shop for $18.
When the 29-year-old hooked up the player he discovered a playlist he could never have imagined - 60 files in total, including the names and personal details of American soldiers.
"The more I look at it, the more I see and the less I think I should be!" he says.
Some of the information appears to be a mission briefing.
ONE News found amongst the files lists of soldiers based in Afghanistan, along with the names of some personnel who have fought in Iraq and cellphones numbers for soldiers based overseas.
ONE News called some of the numbers and the phones are still active.
The files that the numbers were located in are marked with a warning saying the release of its contents is "prohibited by federal law".
There are also details of equipment deployed to the bases and private information about soldiers, such as social security numbers and even which ones are pregnant.
"One of the first rules of military endeavour is not to give the opposition anything whatsoever that they could use to compromise your position, in any way at all," says Peter Cozens of Strategic Studies at Victoria University.
Most of the files found are dated 2005 and seem unlikely to compromise US national security, but experts contacted by ONE News say they could put the individual soldiers at risk.
"This is just slack administrative procedures which are indeed a cause of embarrassment. And it's the sort of thing which ought not really to be in the public domain," says Cozens.
The US Army and the American embassy will not comment.