Scanning a system involves attempting to identify the security vulnerabilities the system may have by sending it specific network traffic and observing its responses. The definition is reasonably specific but can cause confusion—and potentially undue alarm—if it is assumed to include follow-on attempts to exploit any vulnerabilities discovered. Scanning is extremely common on the Internet but may have only a modest success rate, and cyber actors therefore scan far more systems than they actually affect.

Source: Cyber Threats to Elections – A Lexicon, Cyber Threat Intelligence Integration Center & Office of the Director of National Intelligence,