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Detection rules › Kusto

Potential DHCP Starvation Attack

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

'This creates an incident in the event that an excessive amount of DHCPREQUEST have been recieved by a DHCP Server and could potentially be an indication of a DHCP Starvation Attack.'

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT1200 Hardware Additions

Rule body kusto

id: 57e56fc9-417a-4f41-a579-5475aea7b8ce
name: Potential DHCP Starvation Attack
description: |
  'This creates an incident in the event that an excessive amount of DHCPREQUEST have been recieved by a DHCP Server and could potentially be an indication of a DHCP Starvation Attack.'
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: SyslogAma
    datatypes:
      - Syslog
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
relevantTechniques:
  - T1200
query: |
  let threshold = 1000;
  Infoblox
  | where ProcessName =~ "dhcpd" and Log_Type =~ "DHCPREQUEST"
  | summarize count() by SrcIpAddr, bin(TimeGenerated,5m)
  | where count_ > threshold
  | join kind=inner (Infoblox
      | where ProcessName =~ "dhcpd" and Log_Type =~ "DHCPREQUEST"
      ) on SrcIpAddr
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SrcIpAddr
version: 1.0.5
kind: Scheduled

Stages and Predicates

Parameters

let threshold = 1000;

Stage 1: source

Infoblox

Stage 2: where

| where ProcessName =~ "dhcpd" and Log_Type =~ "DHCPREQUEST"

Stage 3: summarize

| summarize count() by SrcIpAddr, bin(TimeGenerated,5m)

Stage 4: where

| where count_ > threshold

Stage 5: join

| join kind=inner (Infoblox
    | where ProcessName =~ "dhcpd" and Log_Type =~ "DHCPREQUEST"
    ) on 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
Log_Typeeq
  • DHCPREQUEST
ProcessNameeq
  • dhcpd
count_gt
  • 1000 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
SrcIpAddrsummarize