Such Adware programs sometimes aren't outright illegal, but exist in a sort of gray area, Bestuzhev told The Post.
"Often, Adware programs do not have any uninstall procedures and use technologies which border on virus technology to help the program stealthily penetrate the computer and run unnoticed," he said in an e-mail. To avoid these risks, Kaspersky recommends using only authorized streams to keep up with the games -- like the video offered by Univision, or the audio stream provided by ESPN radio.
But some fans, in their desperation to get around paying for cable, may still take their chances: In a recent informal online poll run by The Washington Post that yielded more than 1,700 responses, one in five said they watch live sports on "some shady Web site."
Besides schemes associated with sketchy livestream sites, other companies have identified cybercriminals targeting soccer fans through phishing attacks offering free tickets to World Cup games.
Bestuzhev told The Post that the type of Adware his company is seeing on sites aimed at World Cup viewers is "fairly common" on other shady sites claiming to offer streaming video. Scott Montgomery, a vice president at cybersecurity company McAfee, says it's not surprising to see hackers try to take advantage of global interest in something as big as the World Cup by registering official-sounding domains for the purpose of stealing credit cards or installing software on unsuspecting consumers' computers.
"It is not just the World Cup -- any really high demand event site (World Cup, NCAA Final Four, Super Bowl, the UK royals wedding site, etc.) will generate this kind of cyber-leeching,” he told the Post over e-mail.