LONDON-These days, when an unexpected email turns up offering lots of cash, most people just assume it is a scam and delete it.But Mark Litchfield opened one such a message and it led him on a journey that, so far, has netted him about $1.5m (£1.15m) - all of it legitimate.The email was from one-time web giant Yahoo, now owned by Verizon Media, and offered Mr Litchfield several thousand dollars as a reward for finding a bug in its website code.The email was a surprise because he had pretty much forgotten about finding the bug.

“I submitted a bug to Yahoo and thought that was the end of it,” he told BBC News. “And then I got this email saying, ‘Hey, we’ve got some money for you. Do you want it?’”Yahoo had millions wiped off its value because it fell victim to several hack attacks

“That’s when I realised that there was money to be made in this.”