Silk Typhoon Suspicious UM Service Error
| Id | 0625fcce-6d52-491e-8c68-1d9b801d25b9 |
| Rulename | Silk Typhoon Suspicious UM Service Error |
| Description | This query looks for errors that may indicate that an attacker is attempting to exploit a vulnerability in the service. Reference: https://www.microsoft.com/security/blog/2021/03/02/hafnium-targeting-exchange-servers/ |
| Severity | Low |
| Tactics | InitialAccess |
| Techniques | T1190 |
| Kind | Scheduled |
| Query frequency | 1d |
| Query period | 1d |
| Trigger threshold | 0 |
| Trigger operator | gt |
| Source Uri | https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/SilkTyphoonSuspiciousUMServiceError.yaml |
| Version | 1.0.4 |
| Arm template | 0625fcce-6d52-491e-8c68-1d9b801d25b9.json |
Event
| where EventLog =~ "Application"
| where Source startswith "MSExchange"
| where EventLevelName =~ "error"
| where (RenderedDescription startswith "Watson report" and RenderedDescription contains "umworkerprocess" and RenderedDescription contains "TextFormattingRunProperties") or RenderedDescription startswith "An unhandled exception occurred in a UM worker process" or RenderedDescription startswith "The Microsoft Exchange Unified Messaging service" or RenderedDescription contains "MSExchange Unified Messaging"
| where RenderedDescription !contains "System.OutOfMemoryException"
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
| project-away DomainIndex
relevantTechniques:
- T1190
name: Silk Typhoon Suspicious UM Service Error
requiredDataConnectors: []
entityMappings:
- fieldMappings:
- identifier: FullName
columnName: Computer
- identifier: HostName
columnName: HostName
- identifier: NTDomain
columnName: HostNameDomain
entityType: Host
triggerThreshold: 0
id: 0625fcce-6d52-491e-8c68-1d9b801d25b9
tactics:
- InitialAccess
version: 1.0.4
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/SilkTyphoonSuspiciousUMServiceError.yaml
queryPeriod: 1d
kind: Scheduled
metadata:
categories:
domains:
- Security - Threat Intelligence
author:
name: Microsoft Security Research
support:
tier: Community
source:
kind: Community
queryFrequency: 1d
severity: Low
description: |
'This query looks for errors that may indicate that an attacker is attempting to exploit a vulnerability in the service.
Reference: https://www.microsoft.com/security/blog/2021/03/02/hafnium-targeting-exchange-servers/'
query: |
Event
| where EventLog =~ "Application"
| where Source startswith "MSExchange"
| where EventLevelName =~ "error"
| where (RenderedDescription startswith "Watson report" and RenderedDescription contains "umworkerprocess" and RenderedDescription contains "TextFormattingRunProperties") or RenderedDescription startswith "An unhandled exception occurred in a UM worker process" or RenderedDescription startswith "The Microsoft Exchange Unified Messaging service" or RenderedDescription contains "MSExchange Unified Messaging"
| where RenderedDescription !contains "System.OutOfMemoryException"
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
| project-away DomainIndex
triggerOperator: gt
{
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"workspace": {
"type": "String"
}
},
"resources": [
{
"apiVersion": "2024-01-01-preview",
"id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/0625fcce-6d52-491e-8c68-1d9b801d25b9')]",
"kind": "Scheduled",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/0625fcce-6d52-491e-8c68-1d9b801d25b9')]",
"properties": {
"alertRuleTemplateName": "0625fcce-6d52-491e-8c68-1d9b801d25b9",
"customDetails": null,
"description": "'This query looks for errors that may indicate that an attacker is attempting to exploit a vulnerability in the service. \nReference: https://www.microsoft.com/security/blog/2021/03/02/hafnium-targeting-exchange-servers/'\n",
"displayName": "Silk Typhoon Suspicious UM Service Error",
"enabled": true,
"entityMappings": [
{
"entityType": "Host",
"fieldMappings": [
{
"columnName": "Computer",
"identifier": "FullName"
},
{
"columnName": "HostName",
"identifier": "HostName"
},
{
"columnName": "HostNameDomain",
"identifier": "NTDomain"
}
]
}
],
"OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/SilkTyphoonSuspiciousUMServiceError.yaml",
"query": "Event\n| where EventLog =~ \"Application\"\n| where Source startswith \"MSExchange\"\n| where EventLevelName =~ \"error\"\n| where (RenderedDescription startswith \"Watson report\" and RenderedDescription contains \"umworkerprocess\" and RenderedDescription contains \"TextFormattingRunProperties\") or RenderedDescription startswith \"An unhandled exception occurred in a UM worker process\" or RenderedDescription startswith \"The Microsoft Exchange Unified Messaging service\" or RenderedDescription contains \"MSExchange Unified Messaging\"\n| where RenderedDescription !contains \"System.OutOfMemoryException\"\n| extend HostName = tostring(split(Computer, \".\")[0]), DomainIndex = toint(indexof(Computer, '.'))\n| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)\n| project-away DomainIndex\n",
"queryFrequency": "P1D",
"queryPeriod": "P1D",
"severity": "Low",
"subTechniques": [],
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"InitialAccess"
],
"techniques": [
"T1190"
],
"templateVersion": "1.0.4",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0
},
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
}
]
}