SAN FRANCISCO -- The FBI is warning of a potential ATM bank heist that could steal millions of dollars globally, and authorities now have good reason to believe the attack could be carried out within the coming days.There are several steps you can take right now to protect your money.The fraud scheme is typically referred to as an ATM cash out. So, if you haven't changed your password or pin number lately, experts say now would be a very good time.Automated teller machines are potentially under attack across the world. The FBI is now warning American financial institutions about the possibility of cyber criminals carrying out a sophisticated scheme using malware to access personal bank card information."The bank has to do a lot of things on their side to upgrade their firewalls, to upgrade their policies, you know, of dealing with transactions," explains San Jose State University Prof. Dr. Ahmed Banafa.ATM cash outs are more likely to happen at small to medium-sized institutions around the world because they tend to have less security measures in place. Fraudulent copies of debit and credit cards are created by sending the stolen data to the masterminds, who then transfer it to a reusable card with a magnetic stripe."Once they are into the system, they go to the administrative account and they remove any sort of limitations, so whatever's in the bank at that time, they can cash that, and they do it at a pre-determined time, all over the world," Banafa says.The FBI declined to go into greater detail about the warning but said in a statement, "The FBI routinely advises private industry of various cyber threat indicators observed during the course of our investigations. This data is provided in order to help systems administrators guard against the actions of persistent cybercriminals."Despite the threat to financial institutions globally, officials at Technology Credit Union in San Jose are confident their systems are good to go."It is quite common in the financial industry to get alerts like these, and whenever we do, we automatically trigger to our fail safe position, where we increase our monitoring and heighten our alert system to make sure that we are covered," said RS Mukherjee, Technology Credit Union chief information officer.Mukherjee says you should consider changing your password or pin number in the coming days. He also said it's important to monitor your online statements, and to also be on the lookout for any skimming devices when using an ATM."We have all of the IT team, and most of the fraud team, all hands on deck over the weekend, to be able to catch those unusual events, quickly and promptly," said Mukherjee.Experts think the cyber attack could likely happen on a Saturday, when most of the smaller banks around the world tend to be closed for the weekend.