Possible Clues:

• Poison half-a-dozen right in front of us
• Infection viscount's got in game
• Cause of infection (in people and computers)
• Type of protection
• Hacking tool
• Tops vital information rebutted by you and me in Trojan Horse
• Complaint against individual almost certain to be retracted
• Malware, often
• Infection starting very innocently rocks us seriously
• Cause of computer failure?