Final answer:
Identification of attackers and systems occurs in the Identification phase of incident response, which involves detecting the incident's scope and nature.
Step-by-step explanation:
Identifying the attacker(s) and attacking system(s) would occur in the Identification incident response phase. This phase is crucial as it involves detecting and determining the extent of the incident. The main tasks include identifying the nature of the attack, the systems that have been compromised, and the attackers responsible for the incident. In essence, it is about understanding the 'what', 'where', 'when', and 'how' of the incident. Techniques such as analyzing logs, system forensics, and intrusion detection methods are typically employed during this phase.