A tenant whose basic detection rules only notify — email, Slack — creates no
investigation and no alert any API can read: /investigations stays empty and the
Alert Triage API is MDR-gated. The rule's LEQL query is the only artefact left,
so replay it on a schedule and turn every matching line into an alert.
query_log and query_log_set gain:
- an ingest block (results_path events, dedup_key event_id, watermark start_time);
- event_id = log_id + the line's sequence number, the line's own address in Log
Search. It has to be stable across runs because the scheduler deliberately
re-reads the last minute of the previous window on every tick, and anything
derived from the fetch time would make that overlap a second incident. A hash
of (log_id, timestamp, message) covers a source that does not number entries;
- start_time read as ISO-8601, UNIX seconds or milliseconds alike. The API only
takes milliseconds, but which one the scheduler sends is an operator setting on
the rule — the feed must not fetch the wrong window because of a dropdown;
- a bounded page walk (limit, default 1000): unattended every few minutes, a
query matching more than intended would otherwise hold the run open long
enough for the next tick to find it in flight and skip itself;
- detection_name, stamped on every event. The log line does not know which rule
it is being replayed for, and without it an incident is titled by its own first
characters where the source console shows an alert name.
Plus mappers/query_log{,_set}.yaml: the parsed event lives in `message` as a
JSON-encoded string, so account, addresses, asset and process come out through
$parseJson. A raw unparsed line is not JSON — those entries resolve to nothing
and are skipped, and custom:rapid7_log_line still carries the line verbatim.
Severity is left unmapped: a log line has no priority of its own, so the alert
rule's default applies.
Known limits, by construction: this endpoint rejects calculations, so a rule with
a threshold (N occurrences in M minutes) cannot be reproduced — only pattern
rules are 1:1 — and an inactivity rule never can, since it fires on the absence
of events. The query also becomes a copy: editing the rule in InsightIDR leaves
the feed reading the old one.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UjtRtCzw6FEajDDHJ3mTQf
