Detection rules › Kusto

Tomcat - Multiple empty requests from same IP

Status
available
Severity
medium
Time window
5m
Group by
SrcIpAddr
Source
github.com/Azure/Azure-Sentinel

'Detects multiple empty requests from same IP'

MITRE ATT&CK coverage

Rule body kusto

id: 7c9a1026-4872-11ec-81d3-0242ac130003
name: Tomcat - Multiple empty requests from same IP
description: |
  'Detects multiple empty requests from same IP'
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: CustomLogsAma
    datatypes:
      - Tomcat_CL
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
  - Impact
relevantTechniques:
  - T1190
  - T1133
  - T1499
query: |
  let threshold = 50;
  TomcatEvent
  | where HttpResponseBodyBytes == 0
  | summarize MultipleClientErrors = count() by SrcIpAddr, bin(TimeGenerated, 5m)
  | where MultipleClientErrors > threshold
  | extend IPCustomEntity = SrcIpAddr
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPCustomEntity
version: 1.0.2
kind: Scheduled

Stages and Predicates

Parameters

let threshold = 50;

Stage 1: source

TomcatEvent

Stage 2: where

| where HttpResponseBodyBytes == 0

Stage 3: summarize

| summarize MultipleClientErrors = count() by SrcIpAddr, bin(TimeGenerated, 5m)
Threshold
gt 50

Stage 4: where

| where MultipleClientErrors > threshold

Stage 5: extend

| extend IPCustomEntity = SrcIpAddr

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
HttpResponseBodyByteseq
  • 0 transforms: cased
MultipleClientErrorsgt
  • 50 transforms: cased

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

FieldSource
MultipleClientErrorssummarize
SrcIpAddrsummarize
IPCustomEntityextend