The FIRST activity associated with a successful cyber attack is reconnaissance. This is because reconnaissance is a phase of the cyber attack lifecycle that involves gathering information about the target organization or system, such as its network topology, IP addresses, open ports, services, vulnerabilities, etc. Reconnaissance helps to identify potential entry points and weaknesses that can be exploited by the attackers in later phases of the attack. The other options are not the first activity associated with a successful cyber attack, but rather follow after reconnaissance in the cyber attack lifecycle, such as exploitation (A), maintaining a presence C, or creating attack tools (D).