Potential Fodhelper UAC Bypass

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Id	56f3f35c-3aca-4437-a1fb-b7a84dc4af00
Rulename	Potential Fodhelper UAC Bypass
Description	This detection looks for the steps required to conduct a UAC bypass using Fodhelper.exe. By default this detection looks for the setting of the required registry keys and the invoking of the process within 1 hour - this can be tweaked as required.
Severity	Medium
Tactics	PrivilegeEscalation
Techniques	T1548.002
Required data connectors	SecurityEvents WindowsSecurityEvents
Kind	Scheduled
Query frequency	2h
Query period	2h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Windows Security Events/Analytic Rules/PotentialFodhelperUACBypass.yaml
Version	1.0.2
Arm template	56f3f35c-3aca-4437-a1fb-b7a84dc4af00.json

KQL

SecurityEvent
  | where EventID == 4657
  | parse ObjectName with "\\REGISTRY\\" KeyPrefix "\\" RegistryKey
  | project-reorder RegistryKey
  | where RegistryKey has "Software\\Classes\\ms-settings\\shell\\open\\command"
  | extend TimeKey = bin(TimeGenerated, 1h)
  | join (
  SecurityEvent
  | where EventID == 4688
  | where Process =~ "fodhelper.exe"
  | where ParentProcessName endswith "cmd.exe" or ParentProcessName endswith "powershell.exe" or ParentProcessName endswith "powershell_ise.exe"
  | extend TimeKey = bin(TimeGenerated, 1h)) on TimeKey, Computer
  | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
  | extend AccountName = tostring(split(TargetAccount, @'\')[1]), AccountNTDomain = tostring(split(TargetAccount, @'\')[0])

YAML

queryFrequency: 2h
version: 1.0.2
queryPeriod: 2h
id: 56f3f35c-3aca-4437-a1fb-b7a84dc4af00
triggerOperator: gt
triggerThreshold: 0
tactics:
- PrivilegeEscalation
query: |
  SecurityEvent
    | where EventID == 4657
    | parse ObjectName with "\\REGISTRY\\" KeyPrefix "\\" RegistryKey
    | project-reorder RegistryKey
    | where RegistryKey has "Software\\Classes\\ms-settings\\shell\\open\\command"
    | extend TimeKey = bin(TimeGenerated, 1h)
    | join (
    SecurityEvent
    | where EventID == 4688
    | where Process =~ "fodhelper.exe"
    | where ParentProcessName endswith "cmd.exe" or ParentProcessName endswith "powershell.exe" or ParentProcessName endswith "powershell_ise.exe"
    | extend TimeKey = bin(TimeGenerated, 1h)) on TimeKey, Computer
    | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
    | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
    | extend AccountName = tostring(split(TargetAccount, @'\')[1]), AccountNTDomain = tostring(split(TargetAccount, @'\')[0])  
severity: Medium
kind: Scheduled
requiredDataConnectors:
- connectorId: SecurityEvents
  dataTypes:
  - SecurityEvent
- connectorId: WindowsSecurityEvents
  dataTypes:
  - SecurityEvent
entityMappings:
- entityType: Host
  fieldMappings:
  - identifier: FullName
    columnName: Computer
  - identifier: HostName
    columnName: HostName
  - identifier: DnsDomain
    columnName: HostNameDomain
- entityType: Account
  fieldMappings:
  - identifier: FullName
    columnName: TargetAccount
  - identifier: Name
    columnName: AccountName
  - identifier: NTDomain
    columnName: AccountNTDomain
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Windows Security Events/Analytic Rules/PotentialFodhelperUACBypass.yaml
name: Potential Fodhelper UAC Bypass
description: |
    'This detection looks for the steps required to conduct a UAC bypass using Fodhelper.exe. By default this detection looks for the setting of the required registry keys and the invoking of the process within 1 hour - this can be tweaked as required.'
status: Available
relevantTechniques:
- T1548.002

ARM