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Aggregations and Visualizations
TheoryMedium11 minSIEM OperationNetwork Analysis

The Date Histogram: patterns over time

What is it?

A date histogram buckets documents into time intervals (per minute, per hour) and counts each bucket, optionally split by a field. It is the Elastic equivalent of Splunk's timechart — the way you turn time into a visible shape.

Why it matters

Some signals live only in time. A beacon — a host calling home on a fixed interval — is invisible in a document list and under a volume alert, but a per-minute histogram draws it as a flat, evenly-spaced line.

Where you see it

A date histogram with a 1-minute interval, split by destination.domain, over a workstation's proxy events: the malicious destination shows the same small count every minute; normal browsing is irregular.

What normal looks like

An irregular histogram that follows human rhythm — busy hours, quiet nights, uneven bars. Real activity is bursty, not metronomic.

What suspicious looks like

A destination whose bar is the same height in every single interval — a machine cadence. The regularity, not the volume, is the tell; beacons carry almost no data.

How analysts investigate

Add a date histogram with a small interval, split by the entity in question, and look for a bar that repeats identically. Then confirm it is not a legitimate scheduled job before escalating.

Common beginner mistakes

  • Using an interval too coarse (per hour) to reveal a per-minute beacon.
  • Calling every regular pattern malicious — backups and sync jobs are regular too; validate first.

Regularity in time is the signal

  Date histogram, interval 1m, split by destination.domain:
    cdn-updates.example   ▂▅▁▇▂▁▅   ← irregular = human/app browsing
    sync-node7.example    ▁▁▁▁▁▁▁   ← exactly 1 every minute = a beacon
  volume is tiny, so a bandwidth alert never fires — the RHYTHM is the tell
  (this is Splunk's timechart span=1m, in Elastic)
A per-minute date histogram exposes a beacon's fixed rhythm that a document list and volume alerts miss.

Quick check

A host connects to one domain with the same tiny count every minute. Which Elastic view makes it obvious?

A quick self-check — it doesn't affect your XP or progress.

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