Detect instances of multiple server errors occurring within a brief period of time ASIM Web Session
Id | a59ba76c-0205-4966-948e-3d5640140688 |
Rulename | Detect instances of multiple server errors occurring within a brief period of time (ASIM Web Session) |
Description | This detection mechanism identifies situations where multiple server errors originate from a single source within a limited time frame. |
Severity | Medium |
Tactics | InitialAccess Impact |
Techniques | T1190 T1133 T1498 |
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/Web Session Essentials/Analytic Rules/MultipleServerErrorsWithinShortTime.yaml |
Version | 1.0.0 |
Arm template | a59ba76c-0205-4966-948e-3d5640140688.json |
// HTTP response status codes indicate whether a specific HTTP request has been successfully completed.
// Please refer this for more details: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status
let threshold = 100; // You can update threshold value as per your environment
_Im_WebSession(starttime=ago(1h))
| where toint(EventResultDetails) between (500 .. 599)
| summarize
TotalErrorCount = count(),
URLs=make_set(Url, 100),
EventStartTime = min(TimeGenerated),
EventEndTime = max(TimeGenerated),
EventResultDetailsSet=make_set(EventResultDetails,10)
by SrcIpAddr, bin(TimeGenerated, 5m), SrcUsername, SrcHostname
| where TotalErrorCount > threshold
| extend
Name = iif(SrcUsername contains "@", tostring(split(SrcUsername, '@', 0)[0]), SrcUsername),
UPNSuffix = iif(SrcUsername contains "@", tostring(split(SrcUsername, '@', 1)[0]), ""), Threshold=threshold
id: a59ba76c-0205-4966-948e-3d5640140688
relevantTechniques:
- T1190
- T1133
- T1498
tactics:
- InitialAccess
- Impact
kind: Scheduled
severity: Medium
entityMappings:
- entityType: IP
fieldMappings:
- identifier: Address
columnName: SrcIpAddr
- entityType: Account
fieldMappings:
- identifier: Name
columnName: Name
- identifier: UPNSuffix
columnName: UPNSuffix
- entityType: Host
fieldMappings:
- identifier: HostName
columnName: SrcHostname
alertDetailsOverride:
alertDescriptionFormat: "The client has made a total of '{{TotalErrorCount}}' requests to URLs '{{URLs}}', which have resulted in server errors. It is recommended to thoroughly investigate this alert to determine the underlying cause behind this significant number of errors. For detailed information regarding the specific errors encountered, please refer to the following link: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status."
alertDisplayNameFormat: High number of server errors originated by user '{{SrcUsername}}' from IP address '{{SrcIpAddr}}'
name: Detect instances of multiple server errors occurring within a brief period of time (ASIM Web Session)
queryFrequency: 1h
queryPeriod: 1h
customDetails:
RequestURLs: URLs
ErrorThreshold: Threshold
TotalErrorCount: TotalErrorCount
EventStartTime: EventStartTime
EventEndTime: EventEndTime
EventResultSet: EventResultDetailsSet
tags:
- SchemaVersion: 0.2.6
Schema: WebSession
description: |
'This detection mechanism identifies situations where multiple server errors originate from a single source within a limited time frame.'
status: Available
triggerOperator: gt
eventGroupingSettings:
aggregationKind: AlertPerResult
version: 1.0.0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Web Session Essentials/Analytic Rules/MultipleServerErrorsWithinShortTime.yaml
triggerThreshold: 0
query: |
// HTTP response status codes indicate whether a specific HTTP request has been successfully completed.
// Please refer this for more details: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status
let threshold = 100; // You can update threshold value as per your environment
_Im_WebSession(starttime=ago(1h))
| where toint(EventResultDetails) between (500 .. 599)
| summarize
TotalErrorCount = count(),
URLs=make_set(Url, 100),
EventStartTime = min(TimeGenerated),
EventEndTime = max(TimeGenerated),
EventResultDetailsSet=make_set(EventResultDetails,10)
by SrcIpAddr, bin(TimeGenerated, 5m), SrcUsername, SrcHostname
| where TotalErrorCount > threshold
| extend
Name = iif(SrcUsername contains "@", tostring(split(SrcUsername, '@', 0)[0]), SrcUsername),
UPNSuffix = iif(SrcUsername contains "@", tostring(split(SrcUsername, '@', 1)[0]), ""), Threshold=threshold
requiredDataConnectors: []
{
"$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/a59ba76c-0205-4966-948e-3d5640140688')]",
"kind": "Scheduled",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/a59ba76c-0205-4966-948e-3d5640140688')]",
"properties": {
"alertDetailsOverride": {
"alertDescriptionFormat": "The client has made a total of '{{TotalErrorCount}}' requests to URLs '{{URLs}}', which have resulted in server errors. It is recommended to thoroughly investigate this alert to determine the underlying cause behind this significant number of errors. For detailed information regarding the specific errors encountered, please refer to the following link: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status.",
"alertDisplayNameFormat": "High number of server errors originated by user '{{SrcUsername}}' from IP address '{{SrcIpAddr}}'"
},
"alertRuleTemplateName": "a59ba76c-0205-4966-948e-3d5640140688",
"customDetails": {
"ErrorThreshold": "Threshold",
"EventEndTime": "EventEndTime",
"EventResultSet": "EventResultDetailsSet",
"EventStartTime": "EventStartTime",
"RequestURLs": "URLs",
"TotalErrorCount": "TotalErrorCount"
},
"description": "'This detection mechanism identifies situations where multiple server errors originate from a single source within a limited time frame.'\n",
"displayName": "Detect instances of multiple server errors occurring within a brief period of time (ASIM Web Session)",
"enabled": true,
"entityMappings": [
{
"entityType": "IP",
"fieldMappings": [
{
"columnName": "SrcIpAddr",
"identifier": "Address"
}
]
},
{
"entityType": "Account",
"fieldMappings": [
{
"columnName": "Name",
"identifier": "Name"
},
{
"columnName": "UPNSuffix",
"identifier": "UPNSuffix"
}
]
},
{
"entityType": "Host",
"fieldMappings": [
{
"columnName": "SrcHostname",
"identifier": "HostName"
}
]
}
],
"eventGroupingSettings": {
"aggregationKind": "AlertPerResult"
},
"OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Web Session Essentials/Analytic Rules/MultipleServerErrorsWithinShortTime.yaml",
"query": "// HTTP response status codes indicate whether a specific HTTP request has been successfully completed.\n// Please refer this for more details: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status\nlet threshold = 100; // You can update threshold value as per your environment\n_Im_WebSession(starttime=ago(1h))\n| where toint(EventResultDetails) between (500 .. 599)\n| summarize\n TotalErrorCount = count(),\n URLs=make_set(Url, 100),\n EventStartTime = min(TimeGenerated),\n EventEndTime = max(TimeGenerated),\n EventResultDetailsSet=make_set(EventResultDetails,10)\n by SrcIpAddr, bin(TimeGenerated, 5m), SrcUsername, SrcHostname\n| where TotalErrorCount > threshold\n| extend\n Name = iif(SrcUsername contains \"@\", tostring(split(SrcUsername, '@', 0)[0]), SrcUsername),\n UPNSuffix = iif(SrcUsername contains \"@\", tostring(split(SrcUsername, '@', 1)[0]), \"\"), Threshold=threshold\n",
"queryFrequency": "PT1H",
"queryPeriod": "PT1H",
"severity": "Medium",
"status": "Available",
"subTechniques": [],
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"Impact",
"InitialAccess"
],
"tags": [
{
"Schema": "WebSession",
"SchemaVersion": "0.2.6"
}
],
"techniques": [
"T1133",
"T1190",
"T1498"
],
"templateVersion": "1.0.0",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0
},
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
}
]
}