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

Tactic	Techniques
Initial Access	`T1200` Hardware Additions

Rule body

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

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`Log_Type`	eq	`DHCPREQUEST`	`field:"Log_Type" kind:eq value:"DHCPREQUEST"`
`ProcessName`	eq	`dhcpd`	`field:"process_name" kind:eq value:"dhcpd"`
`count_`	gt	`1000`	`field:"count_" kind:gt value:"1000"`

Output fields

These fields are emitted when the rule matches.

Field	Source
`SrcIpAddr`	`summarize`