The Model 650 election machines used in more than half of U.S. states are vulnerable to cyber attacks, according to a report by Ohio’s secretary of state. The high-speed machine is used to count ballots, but an issue in its system could fall victim to election interference.

The Model 650, created by Election Systems & Software LLC, is still sold on the company’s website; however, a spokeswoman for Election Systems told the Wall Street Journal that the machines have not been in production since 2007.

She also said that the election machines are still fairly difficult to hack into in a “real world environment.”

In August, hackers at the Defcon conference discovered flaws many of the election machine systems used across the country and this research was later made into a report.

The report said that most of the security issues with the voting machines are at pique vulnerability when a hacker has physical access to the equipment; however, there are still ways to hack them remotely.

Although Election Systems is confident in its machines, it has worked with state and local legislatures to replace paperless voting machines.

The 2016 presidential election gave rise to fears of election interference when social platforms like Twitter and Facebook discovered that their sites were used by Russian-backed organizations to tamper in the U.S. elections using fake accounts and trolling to influence election results. Russian hackers were also accused by US officials of targeting voting systems in several states.