WASHINGTON -- Computer owners are being encouraged to run security tests on their machines within the next two weeks to ensure they have not been infected by two hacker networks that were seized this week by international law enforcement agencies.
The malware-driven network, called "Gameover Zeus," lifted banking credentials from up to 1 million infected Microsoft Windows computers, according to the United Kingdom's National Crime Agency.
The Wall Street Journal's Market Watch reports the U.S. is home to the highest percentage of Gameover Zeus infections, at 13 percent, according to the Symantec security company.
A second network, using Cryptolocker malware, took command of more than 234,000 computers, demanding ransom payments to unlock files.
Despite the network takedowns, computer owners are scrambling to protect their machines and data.
"U.K. authorities are saying people have this two-week window, in which they need to act with urgency and install anti-malware softwares on their computers and run scans to see if they're protected, and security experts agree," says MarketWatch reporter Priya Anand.
The U.S. Computer Emergency Readiness Team, in the Department of Homeland Security, has posted a list of anti-virus and anti-malware software that users should run.
Anand says security experts believe it generally takes criminals about two weeks to regain control of networks.
"It's not like the world's going to explode after that window ends," says Anand, "but if you have this chance to be safe now, you probably want to act on that."
Signs your computer may have been hacked
Malware can turn computers into bots, or robots that are part of a network called a botnet.
Security experts say there are signs that can help determine whether your computer has been turned into a bot.
One indicator is if the Internet and your computer's programs are running unusually slowly.
"Like you're crawling on the Internet, and it feels like you can make a cup of coffee and eat a sandwich in the amount of time it takes to run a program, that's a warning sign there could be something wrong with your computer, and you might want to run a scan," says Anand.
If you attempt to open a website, and a different website pops up, that indicates a problem.
"That might be a sign that someone else might be controlling what you're doing on your computer," says Anand.
Anand says users should check their computer's activity monitor, or task manager, to see when unfamiliar applications are running.
"If it's something that you didn't open up, or don't have set to automatically open on your computer, that's a huge red flag," says Anand. "There shouldn't be programs running on your computer that you didn't ask to run."
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