Anomaly found in Network Session Traffic ASIM Network Session schema
| Id | cd6def0d-3ef0-4d55-a7e3-faa96c46ba12 |
| Rulename | Anomaly found in Network Session Traffic (ASIM Network Session schema) |
| Description | The rule identifies anomalous pattern in network session traffic based on previously seen data, different Device Action, Network Protocol, Network Direction or overall volume. The rule utilize ASIM normalization, and is applied to any source which supports the ASIM Network Session schema |
| Severity | Medium |
| Tactics | CommandAndControl Discovery Exfiltration LateralMovement |
| Techniques | T1095 T1071 T1046 T1030 T1210 |
| Required data connectors | AIVectraStream AWSS3 AzureFirewall AzureMonitor(VMInsights) AzureNSG CheckPoint CiscoASA CiscoAsaAma CiscoMeraki Corelight Fortinet MicrosoftSysmonForLinux MicrosoftThreatProtection PaloAltoNetworks SecurityEvents WindowsForwardedEvents WindowsSecurityEvents Zscaler |
| Kind | Scheduled |
| Query frequency | 1d |
| Query period | 14d |
| Trigger threshold | 0 |
| Trigger operator | gt |
| Source Uri | https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Network Session Essentials/Analytic Rules/AnomalyFoundInNetworkSessionTraffic.yaml |
| Version | 1.0.1 |
| Arm template | cd6def0d-3ef0-4d55-a7e3-faa96c46ba12.json |
let min_t = ago(14d);
let max_t = now();
let dt = 1d;
let fieldForDvcAction = "DvcAction";
let fieldForNetworkDirection = "NetworkDirection";
let fieldForNetworkProtocol = "NetworkProtocol";
let AnomalyThreshold = 2.5;
let eps = materialize (_Im_NetworkSession | project TimeGenerated | where TimeGenerated > ago(5m) | count | extend Count = Count/300);
let maxSummarizedTime = toscalar (
union isfuzzy=true
(
NetworkCustomAnalytics_protocol_CL
| where EventTime_t > min_t
| summarize max_TimeGenerated=max(EventTime_t)
| extend max_TimeGenerated = datetime_add('minute',10,max_TimeGenerated)
),
(
print(min_t)
| project max_TimeGenerated = print_0
)
| summarize maxTimeGenerated = max(max_TimeGenerated)
);
let nosummary = materialize(
union isfuzzy=true
(
NetworkCustomAnalytics_protocol_CL
| where EventTime_t > ago(1d)
| project v = int(2)
),
(
print int(1)
| project v = print_0
)
| summarize maxv = max(v)
| extend nosum = (maxv > 1)
);
let allData = union isfuzzy=true
(
(datatable(exists:int, nosum:bool)[1,false] | where toscalar(eps) > 1000 | join (nosummary) on nosum) | join (
_Im_NetworkSession(starttime=todatetime(ago(2d)), endtime=now())
| where TimeGenerated > maxSummarizedTime
| summarize Count=count() by NetworkProtocol, DstPortNumber, DstAppName, NetworkDirection, DvcAction, bin(TimeGenerated,10m)
| extend EventTime = TimeGenerated, Count = toint(Count), DstPortNumber = toint(DstPortNumber), exists=int(1)
) on exists
| project-away exists, maxv, nosum*
),
(
(datatable(exists:int, nosum:bool)[1,false] | where toscalar(eps) between (501 .. 1000) | join (nosummary) on nosum) | join (
_Im_NetworkSession(starttime=todatetime(ago(3d)), endtime=now())
| where TimeGenerated > maxSummarizedTime
| summarize Count=count() by NetworkProtocol, DstPortNumber, DstAppName, NetworkDirection, DvcAction, bin(TimeGenerated,10m)
| extend EventTime = TimeGenerated, Count = toint(Count), DstPortNumber = toint(DstPortNumber), exists=int(1)
) on exists
| project-away exists, maxv, nosum*
),
(
(datatable(exists:int, nosum:bool)[1,false] | where toscalar(eps) <= 500 | join (nosummary) on nosum) | join (
_Im_NetworkSession(starttime=todatetime(ago(4d)), endtime=now())
| where TimeGenerated > maxSummarizedTime
| summarize Count=count() by NetworkProtocol, DstPortNumber, DstAppName, NetworkDirection, DvcAction, bin(TimeGenerated,10m)
| extend EventTime = TimeGenerated, Count = toint(Count), DstPortNumber = toint(DstPortNumber), exists=int(1)
) on exists
| project-away exists, maxv, nosum*
),
(
NetworkCustomAnalytics_protocol_CL
| where EventTime_t > min_t
| project-rename NetworkProtocol=NetworkProtocol_s, DstPortNumber=DstPortNumber_d, DstAppName=DstAppName_s, NetworkDirection=NetworkDirection_s, DvcAction=DvcAction_s, Count=count__d, EventTime=EventTime_t
| extend Count = toint(Count),DstPortNumber = toint(DstPortNumber)
)
;
let findVolumneBasedAnomaly = allData
| make-series total=sum(Count) on EventTime from min_t to max_t step dt
| extend (anomalies, score, baseline) = series_decompose_anomalies(total, AnomalyThreshold, -1, 'linefit')
| mv-expand anomalies, score, baseline, EventTime, total
| extend anomalies = toint(anomalies), score = toint(score), baseline = toint(baseline), EventTime = todatetime(EventTime), total = tolong(total)
| where EventTime >= ago(1d)
| where score >= 2*AnomalyThreshold
;
let findAnomalies = (field:string){
allData
| where isnotempty(column_ifexists(field,""))
| make-series total=sum(Count) on EventTime from min_t to max_t step dt by column_ifexists(field,"")
| extend (anomalies, score, baseline) = series_decompose_anomalies(total, AnomalyThreshold, -1, 'linefit')
| mv-expand anomalies, score, baseline, EventTime, total
| extend anomalies = toint(anomalies), score = toint(score), baseline = toint(baseline), EventTime = todatetime(EventTime), total = tolong(total)
| where EventTime >= ago(1d)
| where score >= 2*AnomalyThreshold
};
union findAnomalies(fieldForDvcAction), findAnomalies(fieldForNetworkDirection), findAnomalies(fieldForNetworkProtocol), findVolumneBasedAnomaly
| extend anomalyFieldType = case (isnotempty(column_ifexists(fieldForDvcAction,"")), "DvcAction",
isnotempty(column_ifexists(fieldForNetworkDirection,"")), "NetworkDirection",
isnotempty(column_ifexists(fieldForNetworkProtocol,"")), "NetworkProtocol",
"TotalVolume"
),
anomalyFieldValue = case (isnotempty(column_ifexists(fieldForDvcAction,"")), column_ifexists(fieldForDvcAction,""),
isnotempty(column_ifexists(fieldForNetworkDirection,"")), column_ifexists(fieldForNetworkDirection,""),
isnotempty(column_ifexists(fieldForNetworkProtocol,"")), column_ifexists(fieldForNetworkProtocol,""),
"Overall"
)
relevantTechniques:
- T1095
- T1071
- T1046
- T1030
- T1210
name: Anomaly found in Network Session Traffic (ASIM Network Session schema)
requiredDataConnectors:
- dataTypes:
- AWSVPCFlow
connectorId: AWSS3
- dataTypes:
- DeviceNetworkEvents
connectorId: MicrosoftThreatProtection
- dataTypes:
- SecurityEvent
connectorId: SecurityEvents
- dataTypes:
- SecurityEvent
connectorId: WindowsSecurityEvents
- dataTypes:
- WindowsEvent
connectorId: WindowsForwardedEvents
- dataTypes:
- CommonSecurityLog
connectorId: Zscaler
- dataTypes:
- Syslog
connectorId: MicrosoftSysmonForLinux
- dataTypes:
- CommonSecurityLog
connectorId: PaloAltoNetworks
- dataTypes:
- VMConnection
connectorId: AzureMonitor(VMInsights)
- dataTypes:
- AzureDiagnostics
connectorId: AzureFirewall
- dataTypes:
- AzureDiagnostics
connectorId: AzureNSG
- dataTypes:
- CommonSecurityLog
connectorId: CiscoASA
- dataTypes:
- CommonSecurityLog
connectorId: CiscoAsaAma
- dataTypes:
- Corelight_CL
connectorId: Corelight
- dataTypes:
- VectraStream
connectorId: AIVectraStream
- dataTypes:
- CommonSecurityLog
connectorId: CheckPoint
- dataTypes:
- CommonSecurityLog
connectorId: Fortinet
- dataTypes:
- Syslog
- CiscoMerakiNativePoller
connectorId: CiscoMeraki
triggerThreshold: 0
id: cd6def0d-3ef0-4d55-a7e3-faa96c46ba12
tactics:
- CommandAndControl
- Discovery
- Exfiltration
- LateralMovement
version: 1.0.1
customDetails:
AnomalyFieldType: anomalyFieldType
Score: score
AnomalyFieldValue: anomalyFieldValue
queryPeriod: 14d
alertDetailsOverride:
alertDisplayNameFormat: Anomaly was observed with {{anomalyFieldValue}} Traffic
alertDescriptionFormat: Based on past data, anomaly was observed in {{anomalyFieldValue}} Traffic with a score of {{score}}.
triggerOperator: gt
kind: Scheduled
tags:
- Schema: ASimNetworkSessions
SchemaVersion: 0.2.4
eventGroupingSettings:
aggregationKind: AlertPerResult
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Network Session Essentials/Analytic Rules/AnomalyFoundInNetworkSessionTraffic.yaml
queryFrequency: 1d
severity: Medium
status: Available
description: |
'The rule identifies anomalous pattern in network session traffic based on previously seen data, different Device Action, Network Protocol, Network Direction or overall volume. The rule utilize [ASIM](https://aka.ms/AboutASIM) normalization, and is applied to any source which supports the ASIM Network Session schema'
query: |
let min_t = ago(14d);
let max_t = now();
let dt = 1d;
let fieldForDvcAction = "DvcAction";
let fieldForNetworkDirection = "NetworkDirection";
let fieldForNetworkProtocol = "NetworkProtocol";
let AnomalyThreshold = 2.5;
let eps = materialize (_Im_NetworkSession | project TimeGenerated | where TimeGenerated > ago(5m) | count | extend Count = Count/300);
let maxSummarizedTime = toscalar (
union isfuzzy=true
(
NetworkCustomAnalytics_protocol_CL
| where EventTime_t > min_t
| summarize max_TimeGenerated=max(EventTime_t)
| extend max_TimeGenerated = datetime_add('minute',10,max_TimeGenerated)
),
(
print(min_t)
| project max_TimeGenerated = print_0
)
| summarize maxTimeGenerated = max(max_TimeGenerated)
);
let nosummary = materialize(
union isfuzzy=true
(
NetworkCustomAnalytics_protocol_CL
| where EventTime_t > ago(1d)
| project v = int(2)
),
(
print int(1)
| project v = print_0
)
| summarize maxv = max(v)
| extend nosum = (maxv > 1)
);
let allData = union isfuzzy=true
(
(datatable(exists:int, nosum:bool)[1,false] | where toscalar(eps) > 1000 | join (nosummary) on nosum) | join (
_Im_NetworkSession(starttime=todatetime(ago(2d)), endtime=now())
| where TimeGenerated > maxSummarizedTime
| summarize Count=count() by NetworkProtocol, DstPortNumber, DstAppName, NetworkDirection, DvcAction, bin(TimeGenerated,10m)
| extend EventTime = TimeGenerated, Count = toint(Count), DstPortNumber = toint(DstPortNumber), exists=int(1)
) on exists
| project-away exists, maxv, nosum*
),
(
(datatable(exists:int, nosum:bool)[1,false] | where toscalar(eps) between (501 .. 1000) | join (nosummary) on nosum) | join (
_Im_NetworkSession(starttime=todatetime(ago(3d)), endtime=now())
| where TimeGenerated > maxSummarizedTime
| summarize Count=count() by NetworkProtocol, DstPortNumber, DstAppName, NetworkDirection, DvcAction, bin(TimeGenerated,10m)
| extend EventTime = TimeGenerated, Count = toint(Count), DstPortNumber = toint(DstPortNumber), exists=int(1)
) on exists
| project-away exists, maxv, nosum*
),
(
(datatable(exists:int, nosum:bool)[1,false] | where toscalar(eps) <= 500 | join (nosummary) on nosum) | join (
_Im_NetworkSession(starttime=todatetime(ago(4d)), endtime=now())
| where TimeGenerated > maxSummarizedTime
| summarize Count=count() by NetworkProtocol, DstPortNumber, DstAppName, NetworkDirection, DvcAction, bin(TimeGenerated,10m)
| extend EventTime = TimeGenerated, Count = toint(Count), DstPortNumber = toint(DstPortNumber), exists=int(1)
) on exists
| project-away exists, maxv, nosum*
),
(
NetworkCustomAnalytics_protocol_CL
| where EventTime_t > min_t
| project-rename NetworkProtocol=NetworkProtocol_s, DstPortNumber=DstPortNumber_d, DstAppName=DstAppName_s, NetworkDirection=NetworkDirection_s, DvcAction=DvcAction_s, Count=count__d, EventTime=EventTime_t
| extend Count = toint(Count),DstPortNumber = toint(DstPortNumber)
)
;
let findVolumneBasedAnomaly = allData
| make-series total=sum(Count) on EventTime from min_t to max_t step dt
| extend (anomalies, score, baseline) = series_decompose_anomalies(total, AnomalyThreshold, -1, 'linefit')
| mv-expand anomalies, score, baseline, EventTime, total
| extend anomalies = toint(anomalies), score = toint(score), baseline = toint(baseline), EventTime = todatetime(EventTime), total = tolong(total)
| where EventTime >= ago(1d)
| where score >= 2*AnomalyThreshold
;
let findAnomalies = (field:string){
allData
| where isnotempty(column_ifexists(field,""))
| make-series total=sum(Count) on EventTime from min_t to max_t step dt by column_ifexists(field,"")
| extend (anomalies, score, baseline) = series_decompose_anomalies(total, AnomalyThreshold, -1, 'linefit')
| mv-expand anomalies, score, baseline, EventTime, total
| extend anomalies = toint(anomalies), score = toint(score), baseline = toint(baseline), EventTime = todatetime(EventTime), total = tolong(total)
| where EventTime >= ago(1d)
| where score >= 2*AnomalyThreshold
};
union findAnomalies(fieldForDvcAction), findAnomalies(fieldForNetworkDirection), findAnomalies(fieldForNetworkProtocol), findVolumneBasedAnomaly
| extend anomalyFieldType = case (isnotempty(column_ifexists(fieldForDvcAction,"")), "DvcAction",
isnotempty(column_ifexists(fieldForNetworkDirection,"")), "NetworkDirection",
isnotempty(column_ifexists(fieldForNetworkProtocol,"")), "NetworkProtocol",
"TotalVolume"
),
anomalyFieldValue = case (isnotempty(column_ifexists(fieldForDvcAction,"")), column_ifexists(fieldForDvcAction,""),
isnotempty(column_ifexists(fieldForNetworkDirection,"")), column_ifexists(fieldForNetworkDirection,""),
isnotempty(column_ifexists(fieldForNetworkProtocol,"")), column_ifexists(fieldForNetworkProtocol,""),
"Overall"
)
{
"$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/cd6def0d-3ef0-4d55-a7e3-faa96c46ba12')]",
"kind": "Scheduled",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/cd6def0d-3ef0-4d55-a7e3-faa96c46ba12')]",
"properties": {
"alertDetailsOverride": {
"alertDescriptionFormat": "Based on past data, anomaly was observed in {{anomalyFieldValue}} Traffic with a score of {{score}}.",
"alertDisplayNameFormat": "Anomaly was observed with {{anomalyFieldValue}} Traffic"
},
"alertRuleTemplateName": "cd6def0d-3ef0-4d55-a7e3-faa96c46ba12",
"customDetails": {
"AnomalyFieldType": "anomalyFieldType",
"AnomalyFieldValue": "anomalyFieldValue",
"Score": "score"
},
"description": "'The rule identifies anomalous pattern in network session traffic based on previously seen data, different Device Action, Network Protocol, Network Direction or overall volume. The rule utilize [ASIM](https://aka.ms/AboutASIM) normalization, and is applied to any source which supports the ASIM Network Session schema'\n",
"displayName": "Anomaly found in Network Session Traffic (ASIM Network Session schema)",
"enabled": true,
"entityMappings": null,
"eventGroupingSettings": {
"aggregationKind": "AlertPerResult"
},
"OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Network Session Essentials/Analytic Rules/AnomalyFoundInNetworkSessionTraffic.yaml",
"query": "let min_t = ago(14d);\nlet max_t = now();\nlet dt = 1d;\nlet fieldForDvcAction = \"DvcAction\";\nlet fieldForNetworkDirection = \"NetworkDirection\";\nlet fieldForNetworkProtocol = \"NetworkProtocol\";\nlet AnomalyThreshold = 2.5;\nlet eps = materialize (_Im_NetworkSession | project TimeGenerated | where TimeGenerated > ago(5m) | count | extend Count = Count/300);\nlet maxSummarizedTime = toscalar (\n union isfuzzy=true \n (\n NetworkCustomAnalytics_protocol_CL\n | where EventTime_t > min_t\n | summarize max_TimeGenerated=max(EventTime_t)\n | extend max_TimeGenerated = datetime_add('minute',10,max_TimeGenerated)\n ),\n (\n print(min_t)\n | project max_TimeGenerated = print_0\n )\n | summarize maxTimeGenerated = max(max_TimeGenerated) \n );\nlet nosummary = materialize(\n union isfuzzy=true \n (\n NetworkCustomAnalytics_protocol_CL\n | where EventTime_t > ago(1d) \n | project v = int(2)\n ),\n (\n print int(1) \n | project v = print_0\n )\n | summarize maxv = max(v)\n | extend nosum = (maxv > 1)\n );\nlet allData = union isfuzzy=true \n (\n (datatable(exists:int, nosum:bool)[1,false] | where toscalar(eps) > 1000 | join (nosummary) on nosum) | join (\n _Im_NetworkSession(starttime=todatetime(ago(2d)), endtime=now())\n | where TimeGenerated > maxSummarizedTime\n | summarize Count=count() by NetworkProtocol, DstPortNumber, DstAppName, NetworkDirection, DvcAction, bin(TimeGenerated,10m)\n | extend EventTime = TimeGenerated, Count = toint(Count), DstPortNumber = toint(DstPortNumber), exists=int(1)\n ) on exists\n | project-away exists, maxv, nosum*\n ),\n (\n (datatable(exists:int, nosum:bool)[1,false] | where toscalar(eps) between (501 .. 1000) | join (nosummary) on nosum) | join (\n _Im_NetworkSession(starttime=todatetime(ago(3d)), endtime=now())\n | where TimeGenerated > maxSummarizedTime\n | summarize Count=count() by NetworkProtocol, DstPortNumber, DstAppName, NetworkDirection, DvcAction, bin(TimeGenerated,10m)\n | extend EventTime = TimeGenerated, Count = toint(Count), DstPortNumber = toint(DstPortNumber), exists=int(1)\n ) on exists\n | project-away exists, maxv, nosum*\n ),\n (\n (datatable(exists:int, nosum:bool)[1,false] | where toscalar(eps) <= 500 | join (nosummary) on nosum) | join (\n _Im_NetworkSession(starttime=todatetime(ago(4d)), endtime=now())\n | where TimeGenerated > maxSummarizedTime\n | summarize Count=count() by NetworkProtocol, DstPortNumber, DstAppName, NetworkDirection, DvcAction, bin(TimeGenerated,10m)\n | extend EventTime = TimeGenerated, Count = toint(Count), DstPortNumber = toint(DstPortNumber), exists=int(1)\n ) on exists\n | project-away exists, maxv, nosum*\n ),\n (\n NetworkCustomAnalytics_protocol_CL\n | where EventTime_t > min_t\n | project-rename NetworkProtocol=NetworkProtocol_s, DstPortNumber=DstPortNumber_d, DstAppName=DstAppName_s, NetworkDirection=NetworkDirection_s, DvcAction=DvcAction_s, Count=count__d, EventTime=EventTime_t\n | extend Count = toint(Count),DstPortNumber = toint(DstPortNumber) \n )\n;\nlet findVolumneBasedAnomaly = allData\n | make-series total=sum(Count) on EventTime from min_t to max_t step dt\n | extend (anomalies, score, baseline) = series_decompose_anomalies(total, AnomalyThreshold, -1, 'linefit') \n | mv-expand anomalies, score, baseline, EventTime, total\n | extend anomalies = toint(anomalies), score = toint(score), baseline = toint(baseline), EventTime = todatetime(EventTime), total = tolong(total)\n | where EventTime >= ago(1d)\n | where score >= 2*AnomalyThreshold\n ;\nlet findAnomalies = (field:string){\n allData\n | where isnotempty(column_ifexists(field,\"\"))\n | make-series total=sum(Count) on EventTime from min_t to max_t step dt by column_ifexists(field,\"\")\n | extend (anomalies, score, baseline) = series_decompose_anomalies(total, AnomalyThreshold, -1, 'linefit')\n | mv-expand anomalies, score, baseline, EventTime, total\n | extend anomalies = toint(anomalies), score = toint(score), baseline = toint(baseline), EventTime = todatetime(EventTime), total = tolong(total)\n | where EventTime >= ago(1d)\n | where score >= 2*AnomalyThreshold\n};\nunion findAnomalies(fieldForDvcAction), findAnomalies(fieldForNetworkDirection), findAnomalies(fieldForNetworkProtocol), findVolumneBasedAnomaly\n| extend anomalyFieldType = case (isnotempty(column_ifexists(fieldForDvcAction,\"\")), \"DvcAction\",\n isnotempty(column_ifexists(fieldForNetworkDirection,\"\")), \"NetworkDirection\",\n isnotempty(column_ifexists(fieldForNetworkProtocol,\"\")), \"NetworkProtocol\",\n \"TotalVolume\"\n ),\n anomalyFieldValue = case (isnotempty(column_ifexists(fieldForDvcAction,\"\")), column_ifexists(fieldForDvcAction,\"\"),\n isnotempty(column_ifexists(fieldForNetworkDirection,\"\")), column_ifexists(fieldForNetworkDirection,\"\"),\n isnotempty(column_ifexists(fieldForNetworkProtocol,\"\")), column_ifexists(fieldForNetworkProtocol,\"\"),\n \"Overall\"\n )\n",
"queryFrequency": "P1D",
"queryPeriod": "P14D",
"severity": "Medium",
"status": "Available",
"subTechniques": [],
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"CommandAndControl",
"Discovery",
"Exfiltration",
"LateralMovement"
],
"tags": [
{
"Schema": "ASimNetworkSessions",
"SchemaVersion": "0.2.4"
}
],
"techniques": [
"T1030",
"T1046",
"T1071",
"T1095",
"T1210"
],
"templateVersion": "1.0.1",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0
},
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
}
]
}