What should be the IS auditor's approach to incidents not documented in the risk assessment plan?

The appropriate approach for an IS auditor when encountering incidents not documented in the risk assessment plan is to document them as new risks. This action integrates emerging risks into the organization's overall risk management framework, ensuring that no potential threat is overlooked.

By documenting these incidents, the auditor contributes to the ongoing refinement of the risk assessment process, helping to ensure it reflects the current threat landscape. This practice supports proactive risk management, as it allows the organization to assess the relevance and impact of these new risks on its operations.

Additionally, addressing incidents promptly by updating the risk assessment plan strengthens the organization's risk governance and prepares it to tackle similar incidents in the future. Thus, this approach aligns with best practices in risk management, emphasizing the importance of continuous monitoring and adaptation to new information.