London radio station Last FM has asked its users to change their account passwords after becoming the latest high-profile firm to own up to the possibility of a security breach. LinkedIn and dating site eHarmony also appear to have suffered major password breaches in recent days. Security experts say the latest breach is starting to look like part of a pattern. If a specific vulnerability connects these hacks to one another more breaches will probably follow in the coming days, says one expert. Security expert Graham Cluley: “You have to worry there’s a common vulnerability””]