WASHINGTON — Internet users scanning their Twitter feeds or Facebook accounts might want to add one more quick click to check their computer for malware.
Thousands of people around the country whose computers were infected with malicious software more than a year ago faced the possibility of not being able to get online after midnight Sunday EDT.
At 12:01 a.m. Monday, the FBI planned to shut down the Internet servers set up as a temporary safety net to keep infected computers online for the past eight months. The court order the agency obtained to keep the servers running expired, and it was not renewed.
The problem began when international hackers ran an online advertising scam to take control of more than 570,000 infected computers around the world. When the FBI went in to take down the hackers late last year, agents realized that if they turned off the malicious servers being used to control the computers, all the victims would lose their Internet service.
In a highly unusual move, the FBI set up the safety net. The bureau brought in a private company to install two clean Internet servers to take over for the malicious servers so that people would not suddenly lose their Internet.
The FBI arranged for a private company to run a website — http://www.dcwg.org — as a place where computer users could go to see if their computer was infected and find links to other computer security business sites where they could find fixes for the problem.
From the onset, most victims didn’t even know their computers were infected, although the malicious software probably has slowed their Web surfing and disabled their antivirus software, making their machines more vulnerable to other problems.
Many computer users do not understand the complex machines they use every day to send e-mail, shop, and cruise for information. The cyberworld of viruses, malware, bank fraud, and Internet scams is often distant and confusing, and warning messages may go unseen or unheeded.
Also, some people simply do not trust the government and believe that federal authorities are only trying to spy on them or take over the Internet. Blogs and other Internet forums are riddled with postings warning of the government using the malware as a ploy to breach American citizens’ computers. That is a charge the FBI and other cybersecurity specialists quickly denounce as ridiculous.
As of Wednesday FBI official said there were about 45,600 computers that still may be infected in the United States. Worldwide, the total is roughly 250,000 infected. Recent efforts by Internet service providers may limit the problems on Monday.
Tom Grasso, an FBI supervisory special agent, said many Internet providers have plans to try to help their customers. Some may put technical solutions in place that will correct the server problem. It they do, the Internet will work, but the malware will remain on victims’ computers and could pose future problems.
Other Internet providers are simply braced for the calls to their help lines.