Last week, one of the USA’s largest cellphone service providers, T-Mobile, was targeted by a major cyberattack that impacted over 54 million people. The attackers appear to have accessed the “driver’s license numbers, Social Security numbers and device identification (IMEI and IMSI) numbers” of both past and current customers, as well as prospective customers.

So, if you fall into one of these categories, what should you do? According to the latest report from CNET, experts suggest that you take these four steps to best protect your personal data.

1. Freeze your credit. [This will] prevent anyone with your information from opening a line of credit, or taking out any loans under your name… You’ll just need to fill out a form with Equifax, Experian and Transunion (one from each company) to make the request.

2. Use monitoring services to keep an eye on your credit. There are several credit monitoring services that help you watch your credit report and using one could mean you will receive an alert and hopefully catch false accounts as soon as they happen.

3. Sign up for identity-theft monitoring. In addition to keeping an eye on your Social Security number and credit, an identity-monitoring service will monitor the dark web for anyone selling or trading your personal information or arrests under your name.

4. Use a password manager to create and store logins. Instead of reusing a password — or a series of passwords — rely on a password manager to create, store and autofill your login information.

While at this time, it is unclear exactly what data was accessed in the attack, there is no evidence that suggests customers’ credit card information was compromised. In a press release that came out last week, T-Mobile reported that they will inform everyone who was affected once they are done conducting an investigation into the incident.