Hidden Bluetooth tracker in postcard exposes Dutch warship's location

A journalist at Dutch outlet Omroep Gelderland followed a public mailing address on the Dutch government website and slipped a Bluetooth tracker inside a postcard sent to a naval vessel. The device transmitted location data for roughly a day, revealing the ship sailing from Heraklion toward Cyprus — and by extension hinting at the position of the carrier strike group it was operating with in the Mediterranean.

The tracker was caught within 24 hours of the ship’s arrival, during routine mail sorting, and disabled. Postcards and greeting cards had been exempt from the x-ray screening applied to packages, which is exactly the gap the experiment exploited. The Dutch navy has now banned electronic greeting cards onboard, but the underlying lesson is broader: cheap consumer tracking hardware turns any unscreened inbound item into a potential OPSEC failure for high-value targets.