Cybercriminals are poisoning results when users search for information on the Twitter worm that was unleashed over the weekend, according to security firm F-Secure. The attackers use search-engine optimization tactics so that their malicious sites -- serving up fake anti-virus software -- rank near the top of results. These types of attacks are not uncommon, as opportunists typically leverage popular news or trendy terms to poison search results, F-Secure said. — DK