Spyware affected 18m computer users worldwide
Federal regulators say that 18 million computer users worldwide were affected by malicious spyware allegedly distributed by parties that agreed the day before to a $US2 million ($A2.6 million) settlement.
Analysts and government officials said huge hurdles remain in containing the problem.
The Federal Trade Commission's settlement against two California companies and three individuals was the second-biggest ever made by the agency, bringing the running total to about $US8 million ($A10.45 million) in settlements with more than a dozen companies over the past two years.
