Marriott data breach: practical advice from a cybersecurity expert

The fallout from the hack should be alarming to anyone who has stayed at a Starwood property in the last four years, expert says

A cyber breach in Starwood's reservation system had allowed unauthorised access to information about as many as 500 million guests since 2014. Bloomberg

The potential fallout from the Marriott’s Starwood data breach should be alarming to anyone who has stayed at a Starwood property in the last four years. Not only are guests at risk for opportunistic phishing attacks, but targeted phishing emails are almost certain, as well as phone scams and potential financial fraud. Unlike previous breaches, this attack also included passport numbers for some individuals who are now at increased risk for identity theft. At this point, however, it's unclear what level of exposure each individual victim has been subject to. Until then, all potential victims should assume the worst and take all necessary precautions to protect themselves from all manner of scams.

Sophos, a UK cybersecurity firm, recommends these tips:

Be on alert for "spear phishing"

Marriott has said that personal details associated with the Starwood Preferred Guests accounts have been compromised, and personal email addresses are vulnerable. This creates the perfect scenario for cyber-criminals to actually spear phish consumers because they have this type of detailed information. Spear phishing is the fraudulent practice of sending emails ostensibly from a known or trusted sender in order to induce targeted individuals to reveal confidential information.

Be on alert for opportunistic phishing

Marriott said it will email Starwood Preferred Guests and those who may be impacted. Do not click on links in emails or other communication that seem to have come from Marriott or Starwood hotels. It’s possible that criminals will try to take advantage of this by sending malicious tweets or phishing emails that look like they’ve come from the company. Hover over URLs and links to see the address before you click. Look at the email address to see where it is from

Monitor your financial accounts

Reports indicate the attackers may have access to some members’ encrypted credit card information, but it’s not clear as of yet if this information can be decrypted; in general, monitor your credit card for suspicious activity. As a safety precaution, change the password to your online credit card account. If you use the same password for similar financial management websites, immediately change the password on those websites. As a best security practice, always choose a different, strong password for each sensitive account

Change your passwords

It’s not clear as of yet if the attackers have access to Starwood Preferred Guest account passwords, but as a safety precaution, consumers can change their password. If this password is also used for any financial accounts, change those immediately. Monitor your Starwood Preferred Guest account for suspicious activity

Don’t Google “Web Watcher”

Marriott is offering victims in the USA, UK and Canada a free, one year subscription to something it calls WebWatcher, which it describes as a service that monitors "internet sites where personal information is shared." Don't Google it. If you Google “WebWatcher” you won't find the monitoring service, you'll find lots of links to spyware of the same name. Don't sign up for that. Do follow the links to country-specific versions of the official breach site. You cannot sign up for monitoring from the main breach page, you have to go to the all-but-identical versions of the page for the US, UK or Canada

John Shier is senior security advisor at Sophos