UK-based consumer rights group Which? and tech consultancy 6point6 studied 98 travel sector companies, probing websites, subdomains, employee portals and other web properties with lawful online tools and discovered hundreds of vulnerabilities across major hotel, airline and travel booking websites, some of which have already suffered major breaches.

They found Marriott-owned websites were riddled with 497 bugs including over 100 assessed to be “high” or “critical”. Airline easyJet, which this year revealed a breach affecting nine million customers, was found to have 222 vulnerabilities across nine web domains, including one critical bug that could allow an attacker to hijack users’ browsing sessions and British Airways was found to have 115 vulnerabilities on its websites including 12 judged to be critical. Elsewhere there were 291 potential vulnerabilities found at American Airlines, and a critical vulnerability at Lastminute.com which could allow attackers to create fake log-in accounts.

“Our research suggests that Marriott, British Airways and easyJet have failed to learn lessons from previous data breaches and are leaving their customers exposed to opportunistic cyber-criminals,” argued Which? Travel editor, Rory Boland.