Logic bombs are a type of malware that remain dormant until a specific condition is met. Once triggered, they execute malicious actions, such as deleting files or crashing systems. Unlike viruses, worms, and macro viruses, logic bombs do not replicate themselves or spread to other systems. Instead, they are designed to target specific systems and activate at a predetermined time or event. Therefore, logic bombs align with the given statement that viruses attack when certain conditions are met.