MosaicLoader

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Id	506f4d6b-3864-4bb1-8f75-a13fb066f97a
Rulename	MosaicLoader
Description	This query looks Malware Hides Itself Among Windows Defender Exclusions to Evade Detection.
Severity	High
Tactics	DefenseEvasion
Techniques	T1562
Required data connectors	MicrosoftThreatProtection
Kind	Scheduled
Query frequency	1h
Query period	1h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Defender XDR/Analytic Rules/Exploits/MosaicLoader.yaml
Version	1.0.0
Arm template	506f4d6b-3864-4bb1-8f75-a13fb066f97a.json

KQL

DeviceRegistryEvents 
| where ((ActionType == "RegistryValueSet") and (RegistryKey startswith @"HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows Defender\\Exclusions\\Paths" 
or RegistryKey startswith @"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Extensions"
or RegistryKey startswith @"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Processes"))
| extend HostName = iff(DeviceName has '.', substring(DeviceName, 0, indexof(DeviceName, '.')), DeviceName)
| extend DnsDomain = iff(DeviceName has '.', substring(DeviceName, indexof(DeviceName, '.') + 1), "")

YAML

queryPeriod: 1h
query: |
  DeviceRegistryEvents 
  | where ((ActionType == "RegistryValueSet") and (RegistryKey startswith @"HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows Defender\\Exclusions\\Paths" 
  or RegistryKey startswith @"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Extensions"
  or RegistryKey startswith @"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Processes"))
  | extend HostName = iff(DeviceName has '.', substring(DeviceName, 0, indexof(DeviceName, '.')), DeviceName)
  | extend DnsDomain = iff(DeviceName has '.', substring(DeviceName, indexof(DeviceName, '.') + 1), "")  
name: MosaicLoader
entityMappings:
- fieldMappings:
  - columnName: DeviceName
    identifier: FullName
  - columnName: HostName
    identifier: HostName
  - columnName: DnsDomain
    identifier: DnsDomain
  entityType: Host
- fieldMappings:
  - columnName: RegistryValueName
    identifier: Name
  - columnName: RegistryValueData
    identifier: Value
  entityType: RegistryValue
queryFrequency: 1h
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Defender XDR/Analytic Rules/Exploits/MosaicLoader.yaml
tags:
- MosaicLoader
- Windows Defender Exclusions
requiredDataConnectors:
- connectorId: MicrosoftThreatProtection
  dataTypes:
  - DeviceRegistryEvents
description: |
    This query looks Malware Hides Itself Among Windows Defender Exclusions to Evade Detection.
kind: Scheduled
version: 1.0.0
status: Available
severity: High
relevantTechniques:
- T1562
triggerOperator: gt
triggerThreshold: 0
tactics:
- DefenseEvasion
id: 506f4d6b-3864-4bb1-8f75-a13fb066f97a

ARM