Cost Explorer is an AWS billing and analytics service that shows usage trends and forecasts future cloud spend. It is a financial observability tool: useful for budgeting, but not the final source of invoice truth. Its numbers can differ from actual bills because they are estimates built from partially processed usage data, rounding rules, credits, refunds, and other billing adjustments.
In cyber security, Cost Explorer helps teams spot abnormal spending that may point to compromised accounts, runaway compute jobs, exposed resources, or unexpected crypto-mining activity. Defenders use it for anomaly detection and cost governance, but they must verify spikes against Bills, the Cost and Usage Report, and raw account telemetry before taking action. A broken forecast can trigger false alarms, waste response time, and erode trust in cloud controls.