Brute force attack against a Cloud PC
| Id | 3fbc20a4-04c4-464e-8fcb-6667f53e4987 |
| Rulename | Brute force attack against a Cloud PC |
| Description | Identifies evidence of brute force activity against a Windows 365 Cloud PC by highlighting multiple authentication failures and by a successful authentication within a given time window. |
| Severity | Medium |
| Tactics | CredentialAccess |
| Techniques | T1110 |
| Required data connectors | AzureActiveDirectory |
| Kind | Scheduled |
| Query frequency | 1d |
| Query period | 1d |
| Trigger threshold | 0 |
| Trigger operator | gt |
| Source Uri | https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Entra ID/Analytic Rules/BruteForceCloudPC.yaml |
| Version | 2.0.1 |
| Arm template | 3fbc20a4-04c4-464e-8fcb-6667f53e4987.json |
let authenticationWindow = 20m;
let sensitivity = 2.5;
SigninLogs
| where AppDisplayName =~ "Windows Sign In"
| extend FailureOrSuccess = iff(ResultType in ("0", "50125", "50140", "70043", "70044"), "Success", "Failure")
| summarize FailureCount = countif(FailureOrSuccess=="Failure"), SuccessCount = countif(FailureOrSuccess=="Success"), IPAddresses = make_set(IPAddress,1000)
by bin(TimeGenerated, authenticationWindow), UserDisplayName, UserPrincipalName
| extend FailureSuccessDiff = FailureCount - SuccessCount
| where FailureSuccessDiff > 0
| summarize Diff = make_list(FailureSuccessDiff, 10000), TimeStamp = make_list(TimeGenerated, 10000) by UserDisplayName, UserPrincipalName//, tostring(IPAddresses)
| extend (Anomalies, Score, Baseline) = series_decompose_anomalies(Diff, sensitivity, -1, 'linefit')
| mv-expand Diff to typeof(double), TimeStamp to typeof(datetime), Anomalies to typeof(double), Score to typeof(double), Baseline to typeof(long)
| where Anomalies > 0
| summarize by UserDisplayName, UserPrincipalName, Anomalies, Score, Baseline, FailureToSuccessDiff = Diff
| join kind=leftouter (
SigninLogs
| where AppDisplayName =~ "Windows Sign In"
| extend OS = DeviceDetail.operatingSystem, Browser = DeviceDetail.browser
| extend StatusCode = tostring(Status.errorCode), StatusDetails = tostring(Status.additionalDetails)
| extend State = tostring(LocationDetails.state), City = tostring(LocationDetails.city)
| summarize StartTime = min(TimeGenerated),
EndTime = max(TimeGenerated),
IPAddresses = make_set(IPAddress,100),
OS = make_set(OS,20),
Browser = make_set(Browser,20),
City = make_set(City,100),
ResultType = make_set(ResultType,100)
by UserDisplayName, UserPrincipalName, UserId, AppDisplayName
) on UserDisplayName, UserPrincipalName
| project-away UserDisplayName1, UserPrincipalName1
| extend IPAddressFirst = tostring(IPAddresses[0])
| extend Name = tostring(split(UserPrincipalName,'@',0)[0]), UPNSuffix = tostring(split(UserPrincipalName,'@',1)[0])
relevantTechniques:
- T1110
name: Brute force attack against a Cloud PC
requiredDataConnectors:
- dataTypes:
- SigninLogs
connectorId: AzureActiveDirectory
entityMappings:
- fieldMappings:
- identifier: FullName
columnName: UserPrincipalName
- identifier: Name
columnName: Name
- identifier: UPNSuffix
columnName: UPNSuffix
entityType: Account
- fieldMappings:
- identifier: AadUserId
columnName: UserId
entityType: Account
- fieldMappings:
- identifier: Address
columnName: IPAddressFirst
entityType: IP
triggerThreshold: 0
id: 3fbc20a4-04c4-464e-8fcb-6667f53e4987
tactics:
- CredentialAccess
version: 2.0.1
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Entra ID/Analytic Rules/BruteForceCloudPC.yaml
queryPeriod: 1d
kind: Scheduled
queryFrequency: 1d
severity: Medium
status: Available
description: |
'Identifies evidence of brute force activity against a Windows 365 Cloud PC by highlighting multiple authentication failures and by a successful authentication within a given time window.'
query: |
let authenticationWindow = 20m;
let sensitivity = 2.5;
SigninLogs
| where AppDisplayName =~ "Windows Sign In"
| extend FailureOrSuccess = iff(ResultType in ("0", "50125", "50140", "70043", "70044"), "Success", "Failure")
| summarize FailureCount = countif(FailureOrSuccess=="Failure"), SuccessCount = countif(FailureOrSuccess=="Success"), IPAddresses = make_set(IPAddress,1000)
by bin(TimeGenerated, authenticationWindow), UserDisplayName, UserPrincipalName
| extend FailureSuccessDiff = FailureCount - SuccessCount
| where FailureSuccessDiff > 0
| summarize Diff = make_list(FailureSuccessDiff, 10000), TimeStamp = make_list(TimeGenerated, 10000) by UserDisplayName, UserPrincipalName//, tostring(IPAddresses)
| extend (Anomalies, Score, Baseline) = series_decompose_anomalies(Diff, sensitivity, -1, 'linefit')
| mv-expand Diff to typeof(double), TimeStamp to typeof(datetime), Anomalies to typeof(double), Score to typeof(double), Baseline to typeof(long)
| where Anomalies > 0
| summarize by UserDisplayName, UserPrincipalName, Anomalies, Score, Baseline, FailureToSuccessDiff = Diff
| join kind=leftouter (
SigninLogs
| where AppDisplayName =~ "Windows Sign In"
| extend OS = DeviceDetail.operatingSystem, Browser = DeviceDetail.browser
| extend StatusCode = tostring(Status.errorCode), StatusDetails = tostring(Status.additionalDetails)
| extend State = tostring(LocationDetails.state), City = tostring(LocationDetails.city)
| summarize StartTime = min(TimeGenerated),
EndTime = max(TimeGenerated),
IPAddresses = make_set(IPAddress,100),
OS = make_set(OS,20),
Browser = make_set(Browser,20),
City = make_set(City,100),
ResultType = make_set(ResultType,100)
by UserDisplayName, UserPrincipalName, UserId, AppDisplayName
) on UserDisplayName, UserPrincipalName
| project-away UserDisplayName1, UserPrincipalName1
| extend IPAddressFirst = tostring(IPAddresses[0])
| extend Name = tostring(split(UserPrincipalName,'@',0)[0]), UPNSuffix = tostring(split(UserPrincipalName,'@',1)[0])
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/3fbc20a4-04c4-464e-8fcb-6667f53e4987')]",
"kind": "Scheduled",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/3fbc20a4-04c4-464e-8fcb-6667f53e4987')]",
"properties": {
"alertRuleTemplateName": "3fbc20a4-04c4-464e-8fcb-6667f53e4987",
"customDetails": null,
"description": "'Identifies evidence of brute force activity against a Windows 365 Cloud PC by highlighting multiple authentication failures and by a successful authentication within a given time window.'\n",
"displayName": "Brute force attack against a Cloud PC",
"enabled": true,
"entityMappings": [
{
"entityType": "Account",
"fieldMappings": [
{
"columnName": "UserPrincipalName",
"identifier": "FullName"
},
{
"columnName": "Name",
"identifier": "Name"
},
{
"columnName": "UPNSuffix",
"identifier": "UPNSuffix"
}
]
},
{
"entityType": "Account",
"fieldMappings": [
{
"columnName": "UserId",
"identifier": "AadUserId"
}
]
},
{
"entityType": "IP",
"fieldMappings": [
{
"columnName": "IPAddressFirst",
"identifier": "Address"
}
]
}
],
"OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Entra ID/Analytic Rules/BruteForceCloudPC.yaml",
"query": "let authenticationWindow = 20m;\nlet sensitivity = 2.5;\nSigninLogs\n| where AppDisplayName =~ \"Windows Sign In\"\n| extend FailureOrSuccess = iff(ResultType in (\"0\", \"50125\", \"50140\", \"70043\", \"70044\"), \"Success\", \"Failure\")\n| summarize FailureCount = countif(FailureOrSuccess==\"Failure\"), SuccessCount = countif(FailureOrSuccess==\"Success\"), IPAddresses = make_set(IPAddress,1000)\n by bin(TimeGenerated, authenticationWindow), UserDisplayName, UserPrincipalName\n| extend FailureSuccessDiff = FailureCount - SuccessCount\n| where FailureSuccessDiff > 0\n| summarize Diff = make_list(FailureSuccessDiff, 10000), TimeStamp = make_list(TimeGenerated, 10000) by UserDisplayName, UserPrincipalName//, tostring(IPAddresses)\n| extend (Anomalies, Score, Baseline) = series_decompose_anomalies(Diff, sensitivity, -1, 'linefit') \n| mv-expand Diff to typeof(double), TimeStamp to typeof(datetime), Anomalies to typeof(double), Score to typeof(double), Baseline to typeof(long)\n| where Anomalies > 0\n| summarize by UserDisplayName, UserPrincipalName, Anomalies, Score, Baseline, FailureToSuccessDiff = Diff\n| join kind=leftouter (\n SigninLogs\n | where AppDisplayName =~ \"Windows Sign In\"\n | extend OS = DeviceDetail.operatingSystem, Browser = DeviceDetail.browser\n | extend StatusCode = tostring(Status.errorCode), StatusDetails = tostring(Status.additionalDetails)\n | extend State = tostring(LocationDetails.state), City = tostring(LocationDetails.city)\n | summarize StartTime = min(TimeGenerated), \n EndTime = max(TimeGenerated), \n IPAddresses = make_set(IPAddress,100), \n OS = make_set(OS,20), \n Browser = make_set(Browser,20), \n City = make_set(City,100), \n ResultType = make_set(ResultType,100)\n by UserDisplayName, UserPrincipalName, UserId, AppDisplayName\n ) on UserDisplayName, UserPrincipalName\n| project-away UserDisplayName1, UserPrincipalName1\n| extend IPAddressFirst = tostring(IPAddresses[0])\n| extend Name = tostring(split(UserPrincipalName,'@',0)[0]), UPNSuffix = tostring(split(UserPrincipalName,'@',1)[0])\n",
"queryFrequency": "P1D",
"queryPeriod": "P1D",
"severity": "Medium",
"status": "Available",
"subTechniques": [],
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"CredentialAccess"
],
"techniques": [
"T1110"
],
"templateVersion": "2.0.1",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0
},
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
}
]
}