More than 25 million people are expected to travel by air during this year’s Thanksgiving season, making it one of the busiest on record, according to the Transportation Security Administration. Although an increased number of travelers may be good for airline companies, it poses a cybersecurity problem.

“More people in airports using public Wi-Fi means that hackers have more targets,” said Dr. Michael Nowatkowski, associate professor of information security at the School of Computer and Cyber Sciences at Augusta University. “Hackers take advantage of large crowds to increase their chances of a successful attack. If people don’t take precautions, they could become victims. Business travelers should be even more cautious because they could give away their company’s confidential information.”

Because cybersecurity at airports has become a pressing problem, cloud security company Coronet recently analyzed the vulnerabilities of the 45 busiest airports in the country.

Based on their findings, the company created a threat index score and divided the severity of the threat into three categories: red for severe risk of being hacked, orange for medium risk and yellow for low risk.

Of the 45 airports analyzed, 18 fall in the red category with San Diego International Airport leading the list of the most insecure airports when it comes to online safety. Charlotte Douglas International Airport came in eighth. At these airports, Coronet recommends that travelers never connect to public Wi-Fi without properly protecting their devices.

Although Hartsfield Jackson Atlanta International Airport did not make top 10, it fell in the orange category. Travelers going through airports in this category should have proper software protection on their devices that can identify malicious networks. They should also only connect to legitimate Wi-Fi networks.

Nowatkowski recommends that travelers take the following steps to ensure their devices and information are protected:

• Apply any software updates, which may include security updates, to your devices while connected to your home network;

• Always use original operating systems on your devices;

• Download and update anti-virus and anti-malware programs on all devices you will be traveling with;

• Before connecting to public Wi-Fi, make sure the network is legitimate (hackers can create malicious networks with the same name as legitimate networks and trick you or your device into connecting to them);

• Only use public Wi-Fi for activities that do not involve sensitive or personal information, such as checking reading the news or checking the weather;

• Never use public Wi-Fi for bank transactions, purchases or bill payments (it’s safer to use your 4G or LTE network for these activities);

• Never update your devices while connected to public Wi-Fi (hackers can trick your devices into installing malicious programs during the update process;

• Make sure you turn off your devices’ Wi-Fi, Bluetooth, file sharing and air drop (hackers can use those connections to hack into your devices).