"Overall, the USA infection rates have been slower than the rest of the world, but we may still see significant impacts in additional networks as these malware attacks morph and change", said Bossert.
Another part of being prepared for an attack is to have a back-up plan if your computer becomes infected.
As companies around the world have patched their Microsoft (MSFT) Windows operating systems, the next round of WannaCry ransomware could strike organizations that have not uploaded security fixes.
The attacks affected 150 countries and infected at least 200,000 computers worldwide, despite global cyber security firms warning last month that they were expected.
A ransomware attack has swept through more than 150 countries across the globe.
Instead of developing hacking tools in secret and holding them for use against adversaries, governments and intelligence agencies should share weaknesses they find with Microsoft and other software makers so that vulnerabilities can be repaired, he said.
The malware spread because of flaws in old versions of Windows originally identified by the NSA to hack into PCs before being made public by the Shadow Brokers group in April.
European policing and security agencies said the fallout from a ransomware attack that has already crippled more than 200,000 computers around the world could deepen as people return for another work week. An equivalent scenario with conventional weapons would be the US military having some of its Tomahawk missiles stolen.
Experts are still trying to determine who launched the ransomware attack.
WannaCry takes advantage of a Microsoft Windows vulnerability. "The fact that so many computers remained vulnerable two months after the release of a patch illustrates this aspect".
Ransomware known as "WannaCry" was unleashed on Friday and exploited vulnerabilities in outdated versions of Microsoft Windows.
Mr Smith argued that in cyberspace, governments should apply rules such as those regarding weapons in the physical world.
Victims are expected to contact the criminals for a key to unlock their files, said security expert Prof Alan Woodward, from the University of Surrey.
Microsoft has updated its security software to deal with the crisis.
One theory suggested that 90 percent of NHS trusts across the United Kingdom were using Microsoft's 16-year-old OS Windows XP, which could leave them susceptible to attacks.
For those running Windows 10 or Windows Vista, Windows 7 and Windows 8.1 systems, which has automatic updates turned on, you'll remain protected from WannaCry.