Criminals are capitalizing on a busy sports summer to fool people into clicking on soccer, golf and even paintball sites infested with malicious programs that can compromise privacy or worse, says a Czech Republic-based security software seller.

The sites are on what Prague-based Avast Software calls its monthly "Most Wanted" list. The World Cup, the LeBron James spectacle and baseball season are particular targets for search-engine gaming, the company says. Criminals seek to trick people into clicking on sites that seem to be legitimate -- or that are legitimate, but infected without the operator's knowledge -- so that malicious programs can be downloaded to personal computers.

The worst of these programs can allow a criminal to take control of a personal computer and use it for wrongdoing. Others can download programs such as keystroke loggers that compile passwords and distribute them to third parties.

Avast sells security software, but also provides free copies of its active anti-virus software on its website. Information for its "Most Wanted" list is culled from a community of users that volunteer to report the results of problem websites they find.

Other security software companies, such as McAfee, compile lists in a similar spirit.

Here's the current list of most-infected sites, several of which are blocked at the browser level by Firefox:

cybergolf.com (appears to be legitimate)
elitepaintballguns.com
footballfevr.com
joinfutbol.com
mosportsmen.com
sport-pros.com
sportsroids.com
sportxsport.com
topsportzone.com
u-soccer.com

During the World Cup, Avast says it noticed a 200% increase in infected web pages at the co.za country code domain.