In what's perhaps the biggest data privacy scandal of the year after the Facebook and Cambridge Analytica fiasco, hotel chain Marriott's reservation database has been hacked, which could affect hundreds of millions of guests who have stayed at the hotel or any of its properties since 2014.

Announcing the news in a press release, the company said it first learned of this breach on Sept. 8, stating that an authorized part had tried to access the guest reservation database for its Starwood properties.

Marriott Data Breach Explained

A subsequent investigation then revealed that there had been "unauthorized access to the Starwood network since 2014" and that the personal information of about 500 million guests had been compromised. The type of information stolen varies. For 327 million of those guests, the data breach included "some combination of name, mailing address, phone number, email address, passport number, Starwood Preferred Guest ('SPG') account information, date of birth, gender, arrival and departure information, reservation date, and communication preferences," according to Marriott.

What Are The Affected Hotels?

The hack affects guests who have stayed at Marriott's Starwood hotels since 2014. Below is a list of such properties:

• W Hotels

• The St. Regis

• Sheraton Hotels & Resorts

• Westin Hotels & Resorts

• Element Hotels

• Aloft Hotels

• The Luxury Collection

• Tribute Portfolio

• Le Méridien Hotels & Resorts

• Four Points by Sheraton

• Design Hotels

• Starwood-branded timeshares

What To Do If You Think You're Affected

The company said it'll send emails to affected guests whose information may have been compromised in the data breach. It has also put up a website with detailed information about the incident, in addition to a call center for guests who might have questions or are concerned about their information potentially being stolen. Marriott advises customers to remain vigilant, as bad agents might try to pose as the company by sending convincing but fake emails.

For those who made a reservation with any of the aforementioned hotels on or before Sept. 10, chances are their information has been stolen, according to Marriott. To make sure none of that goes out, the company is offering affected guests a year's worth of fraud monitoring services for free. This includes a tool called WebWatcher, which will monitor websites where personal data is shared and alerts customers if their information is found.

Websites such as Wired have also put up dedicated guides to make sure everyone's information is protected. Some of the safeguards are pretty basic, such as changing one's password, PIN codes, and other pertinent security keys.

Online tools such as HaveIBeenPwned are also useful to check whether one's private data has been compromised.

Make sure to check back with Tech Times as we learn more.