Detection rules › Kusto

SlackAudit - User email linked to account changed.

Status
available
Severity
medium
Time window
14d
Group by
SrcUserEmail, SrcUserName
Source
github.com/Azure/Azure-Sentinel

'Detects when user email linked to account changes.'

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT1078 Valid Accounts

Rule body kusto

id: 9d85feb3-7f54-4181-b143-68abb1a86823
name: SlackAudit - User email linked to account changed.
description: |
  'Detects when user email linked to account changes.'
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: SlackAuditAPI
    dataTypes:
      - SlackAudit_CL
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
relevantTechniques:
  - T1078
query: |
  SlackAudit
  | where TimeGenerated between (ago(14d) .. (1d))
  | summarize max(TimeGenerated) by SrcUserName, SrcUserEmail
  | join (SlackAudit 
        | where Action =~ 'user_login'
        | project SrcIpAddr, SrcUserName, NewUserEmail = SrcUserEmail) on SrcUserName
  | where NewUserEmail != SrcUserEmail
  | extend AccountCustomEntity = SrcUserName
  | extend IPCustomEntity = SrcIpAddr
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: AccountCustomEntity
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPCustomEntity
alertDetailsOverride:
  alertDisplayNameFormat: Slack user email changed for {{SrcUserName}}
  alertDescriptionFormat: Slack audit detected a user email change for {{SrcUserName}} from {{SrcUserEmail}} to {{NewUserEmail}}.
customDetails:
  SourceUserName: SrcUserName
  OriginalUserEmail: SrcUserEmail
  NewUserEmail: NewUserEmail
  SourceIpAddress: SrcIpAddr
version: 1.0.1
kind: Scheduled

Stages and Predicates

Stage 1: source

SlackAudit

Stage 2: where

| where TimeGenerated between (ago(14d) .. (1d))

Stage 3: summarize

| summarize max(TimeGenerated) by SrcUserName, SrcUserEmail

Stage 4: join

| join (SlackAudit 
      | where Action =~ 'user_login'
      | project SrcIpAddr, SrcUserName, NewUserEmail = SrcUserEmail) on SrcUserName

Stage 5: where

| where NewUserEmail != SrcUserEmail

Stage 6: extend

| extend AccountCustomEntity = SrcUserName

Stage 7: 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
Actioneq
  • user_login
NewUserEmailne
  • SrcUserEmail 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
SrcUserEmailsummarize
SrcUserNamesummarize
AccountCustomEntityextend
IPCustomEntityextend