Plenty of people take to social media to express their excitement at going on holiday - and posting an image of their boarding pass online is a popular way to boast about it.
But did you know the information on this seemingly harmless piece of paper could reveal a lot more about you than your flight number and destination?
See also: Revealed: Why airport shops really want to see your boarding pass
Cyber security expert and blogger Brian Krebs recently relayed a story about one of his reader's attempts to get hold of this hidden information.
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The reader spotted a boarding pass posted by one of his friends on Facebook and decided to use a simple online scanner (these are freely available online and very simple to use) to get into his friend's Lufthansa account.
By scanning the barcode online, he found the record locator for the flight and managed to gain access to his friend's frequent flyer account using that information along with his friend's surname.
He could then see every future flight his friend was booked on and had the ability to change seats and even cancel flights.
His friend's phone number and the name of the person who had booked each flight was also readily available.
On his blog, Krebs notes that such access could easily be exploited by attackers and suggests shredding old boarding passes instead of just throwing them away.
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