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Detection rules › Kusto

API - Account Takeover

Status
available
Severity
high
Time window
5m
Source
github.com/Azure/Azure-Sentinel

'42Crunch API protection against account takeover'

MITRE ATT&CK coverage

TacticTechniques
Credential Access
Discovery

Rule body

id: 25c86f99-0a91-4b7f-88f3-599a008e5ab8
name: API - Account Takeover
description: |
  '42Crunch API protection against account takeover'
severity: High
requiredDataConnectors:
  - connectorId: 42CrunchAPIProtection
    dataTypes:
      - FortyTwoCrunchAPIProtection
  - connectorId: FortyTwoCrunchAPIProtection
    dataTypes:
      - FortyTwoCrunchAPIProtection
queryFrequency: 5m
queryPeriod: 5m
triggerOperator: gt
triggerThreshold: 0
eventGroupingSettings:
  aggregationKind: SingleAlert
status: Available
tactics:
  - CredentialAccess
  - Discovery
relevantTechniques:
  - T1110
  - T1087
query: |
  let firstRec = FortyTwoCrunchAPIProtection
  | where TimeGenerated >= ago(5m) 
  | project-away NonBlockingMode, SourcePort, DestinationPort, Query, ApiId, RequestHeader, ResponseHeader, Errors, EventType, Uuid
  | where (UriPath has "/api/register" or UriPath has "/api/reset") and Status == 403;
  let recCount = iff((toscalar(firstRec | count) >= 20), 1, 0);
  firstRec | take recCount
customDetails:
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SourceIp
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: Hostname
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: InstanceName
version: 3.0.1
kind: Scheduled

Stages and Predicates

let firstRec is inlined into the numbered stages below.

Let binding: recCount used in Stage 5

let recCount = iff((toscalar(firstRec | count) >= 20), 1, 0);

Stages 1 to 4 define let firstRec (the rule's main pipeline source); stage 5 runs on it.

Stage 1: source

FortyTwoCrunchAPIProtection

Stage 2: where

| where TimeGenerated >= ago(5m)

Stage 3: project-away

| project-away NonBlockingMode, SourcePort, DestinationPort, Query, ApiId, RequestHeader, ResponseHeader, Errors, EventType, Uuid

Stage 4: where

| where (UriPath has "/api/register" or UriPath has "/api/reset") and Status == 403

Stage 5: take

firstRec
| take recCount

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
Statuseq
  • 403
field:"Status" kind:eq value:"403"
UriPathmatch
  • /api/register transforms: term
  • /api/reset transforms: term
field:"UriPath" kind:match