Because we needed another reason to keep us up at night.

The latest cause for concern is WannaCry, a bit of so-called ransomware that locks up your computer and holds it hostage until you pay the hackers. Ransomware isn't new, but the difference here is scale: As of Sunday, more than 100,000 organizations in at least 150 countries had been affected, making this the largest cyber-extortion scheme ever (you can actually watch a real-time map of affected computers).

It's scary enough stuff, but what really chills the bone is the idea that this is just the beginning. The speed and reach of WannaCry, as well as its ability to evolve, is just the latest example of the new age of cyberterrorism that we live in. It's one where hackers can influence the US election, pilfer your personal information or hold up critical life-saving systems in hospitals. And because of our dependence on technology, there are no easy solutions.

"The WannaCry ransomware outbreak is a wakeup call for the world," said Andreas Kuehlmann, senior vice president of the software integrity group at software provider Synopsys. "It highlights not only our interconnectedness and deep-seated dependence on technology, but the massive challenge we face in securing the ecosystem of software and systems we rely on."

With new cases cropping up over the weekend in China and Japan, it's no wonder millions of people walked into their offices if they too were victims of WannaCry. Or worse: If WannaCry evolves into something even more dangerous and widespread.

WannaCry has already shown the ability to change. An analyst from MalwareTech on Friday stumbled upon a way to halt the attack by unwittingly activating a kill switch, By Monday, hackers had changed the code so that kill switch no longer worked.

Genesis of WannaCry

WannaCry, also known as WanaCrypt0r 2.0, is able to get into Windows systems by exploiting a vulnerability called EternalBlue, which was first discovered by the NSA and leaked by the hacker group Shadow Brokers in April. The updated version that debuted today also uses the same exploits.

WannaCry enters a system through an email attachment and can spread through the local area network through a standard file sharing technology called Windows Server Message Block, or SMB. Hospitals in the UK's National Health Service, Spanish telecommunications provider Telefonica and Fedex were among the early organizations hit, and it spread from there.

"It shows how the criminals really have the upper hand in this situation and most companies are completely unprepared for this kind of attack," said Gartner analyst Avivah Litan.

The hackers typically demand about $300 in payment via bitcoin, an untraceable digital currency often used on shadowy parts of the internet. If that ransom isn't paid in 72 hours, the price could double. And after a few days, the files are permanently locked.

Hackers could stand to make more than a billion dollars if the ransoms are all paid.

Outdated equipment

Microsoft believes that government agencies like the CIA hoarding software flaws and keeping them secret contributed to WannaCry.

While Microsoft has patched up the vulnerabilities in newer versions of Windows, that left computers running older software still open to attack. And guess what? A lot of people still use Windows XP. Likewise, if you don't have a licensed version of Windows (you stole it), you may not have the necessary patches to protect you.

The effectiveness of WannaCry underscored the fact that many of these computers are using older software and haven't been updated or patched.

"As we look at the overall cybersecurity posture of the country, we have to look at the way we manage old platforms and better protect them," said Mark Testoni, CEO of security software company SAP NS2.

Still evolving?

Today's problem may just be the beginning. The real fear is that this set off a new wave of attacks. Hackers have already updated WannaCry. What's next?

"The concern being that potentially a new variant of this ransomware could show up on Monday," said Adam Meyers, vice president of intelligence at Crowd Strike, told CBS News. "And it would take a lot more effort to try to stop that next wave of attack."

Copycats are already starting to pop up, according to security experts.

That's really what's keeping security professionals awake at night.

"So we have the WannaCry thing. They'll say, 'did you fix it?' 'Well, we fixed the glitch. We've patched the ones that have been infected. Great, so we're good,'" said Yahoo Chief Information Security Officer Bob Lord at TechCrunch Disrupt on Monday. "But that transactional relationship isn't going to prepare you for a truly intelligent adversary who really is out to get you."