Office 365 - SharePointFileOperation via devices with previously unseen user agents

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Id	efd17c5f-5167-40f8-a1e9-0818940785d9
Rulename	Office 365 - SharePointFileOperation via devices with previously unseen user agents
Description	Identifies anomalies if the number of documents uploaded or downloaded from device(s) associated with a previously unseen user agent exceeds a threshold (default is 5) and deviation (default is 25%).
Severity	Medium
Tactics	Exfiltration
Techniques	T1030
Required data connectors	AzureActiveDirectory
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/Global Secure Access/Analytic Rules/Office 365 - SharePoint_Downloads_byNewUserAgent.yaml
Version	2.2.5
Arm template	efd17c5f-5167-40f8-a1e9-0818940785d9.json

KQL

// Set threshold for the number of downloads/uploads from a new user agent
let threshold = 5;
// Define constants for SharePoint file operations
let szSharePointFileOperation = "SharePointFileOperation";
let szOperations = dynamic(["FileDownloaded", "FileUploaded"]);
// Define the historical activity for analysis
let starttime = 14d; // Define the start time for historical data (14 days ago)
let endtime = 1d;   // Define the end time for historical data (1 day ago)
// Extract the base events for analysis
let Baseevents =
    EnrichedMicrosoft365AuditLogs
    | where TimeGenerated between (ago(starttime) .. ago(endtime))
    | where RecordType == szSharePointFileOperation
    | where Operation in (szOperations)
    | extend UserAgent = tostring(parse_json(tostring(AdditionalProperties)).UserAgent)
    | extend Site_Url = tostring(parse_json(tostring(AdditionalProperties)).SiteUrl)
    | where isnotempty(UserAgent);
// Identify frequently occurring user agents
let FrequentUA = Baseevents
    | summarize FUACount = count() by UserAgent, RecordType, Operation
    | where FUACount >= threshold
    | distinct UserAgent;
// Calculate a user baseline for further analysis
let UserBaseLine = Baseevents
    | summarize Count = count() by UserId, Operation, Site_Url
    | summarize AvgCount = avg(Count) by UserId, Operation, Site_Url;
// Extract recent activity for analysis
let RecentActivity = EnrichedMicrosoft365AuditLogs
    | where TimeGenerated > ago(endtime)
    | where RecordType == szSharePointFileOperation
    | where Operation in (szOperations)
    | extend UserAgent = tostring(parse_json(tostring(AdditionalProperties)).UserAgent)
    | extend Site_Url = tostring(parse_json(tostring(AdditionalProperties)).SiteUrl)
    | where isnotempty(UserAgent)
    | where UserAgent in (FrequentUA)
    | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), ObjectIdCount = dcount(ObjectId), ObjectIdList = make_set(ObjectId), UserAgentSeenCount = count()
    by RecordType, Operation, UserAgent, UserId, ClientIp, Site_Url;
// Analyze user behavior based on baseline and recent activity
let UserBehaviorAnalysis = UserBaseLine
    | join kind=inner (RecentActivity) on UserId, Operation, Site_Url
    | extend Deviation = abs(UserAgentSeenCount - AvgCount) / AvgCount;
// Filter and format results for specific user behavior analysis
UserBehaviorAnalysis
    | where Deviation > 0.25
    | extend UserIdName = tostring(split(UserId, '@')[0]), UserIdUPNSuffix = tostring(split(UserId, '@')[1])
    | project-reorder StartTime, EndTime, UserAgent, UserAgentSeenCount, UserId, ClientIp, Site_Url
    | order by UserAgentSeenCount desc, UserAgent asc, UserId asc, Site_Url asc

YAML

queryPeriod: 14d
version: 2.2.5
tactics:
- Exfiltration
queryFrequency: 1d
id: efd17c5f-5167-40f8-a1e9-0818940785d9
triggerOperator: gt
requiredDataConnectors:
- dataTypes:
  - EnrichedMicrosoft365AuditLogs
  connectorId: AzureActiveDirectory
severity: Medium
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: UserId
    identifier: FullName
  - columnName: UserIdName
    identifier: Name
  - columnName: UserIdUPNSuffix
    identifier: UPNSuffix
- entityType: IP
  fieldMappings:
  - columnName: ClientIp
    identifier: Address
- entityType: URL
  fieldMappings:
  - columnName: Site_Url
    identifier: Url
triggerThreshold: 0
relevantTechniques:
- T1030
query: |
  // Set threshold for the number of downloads/uploads from a new user agent
  let threshold = 5;
  // Define constants for SharePoint file operations
  let szSharePointFileOperation = "SharePointFileOperation";
  let szOperations = dynamic(["FileDownloaded", "FileUploaded"]);
  // Define the historical activity for analysis
  let starttime = 14d; // Define the start time for historical data (14 days ago)
  let endtime = 1d;   // Define the end time for historical data (1 day ago)
  // Extract the base events for analysis
  let Baseevents =
      EnrichedMicrosoft365AuditLogs
      | where TimeGenerated between (ago(starttime) .. ago(endtime))
      | where RecordType == szSharePointFileOperation
      | where Operation in (szOperations)
      | extend UserAgent = tostring(parse_json(tostring(AdditionalProperties)).UserAgent)
      | extend Site_Url = tostring(parse_json(tostring(AdditionalProperties)).SiteUrl)
      | where isnotempty(UserAgent);
  // Identify frequently occurring user agents
  let FrequentUA = Baseevents
      | summarize FUACount = count() by UserAgent, RecordType, Operation
      | where FUACount >= threshold
      | distinct UserAgent;
  // Calculate a user baseline for further analysis
  let UserBaseLine = Baseevents
      | summarize Count = count() by UserId, Operation, Site_Url
      | summarize AvgCount = avg(Count) by UserId, Operation, Site_Url;
  // Extract recent activity for analysis
  let RecentActivity = EnrichedMicrosoft365AuditLogs
      | where TimeGenerated > ago(endtime)
      | where RecordType == szSharePointFileOperation
      | where Operation in (szOperations)
      | extend UserAgent = tostring(parse_json(tostring(AdditionalProperties)).UserAgent)
      | extend Site_Url = tostring(parse_json(tostring(AdditionalProperties)).SiteUrl)
      | where isnotempty(UserAgent)
      | where UserAgent in (FrequentUA)
      | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), ObjectIdCount = dcount(ObjectId), ObjectIdList = make_set(ObjectId), UserAgentSeenCount = count()
      by RecordType, Operation, UserAgent, UserId, ClientIp, Site_Url;
  // Analyze user behavior based on baseline and recent activity
  let UserBehaviorAnalysis = UserBaseLine
      | join kind=inner (RecentActivity) on UserId, Operation, Site_Url
      | extend Deviation = abs(UserAgentSeenCount - AvgCount) / AvgCount;
  // Filter and format results for specific user behavior analysis
  UserBehaviorAnalysis
      | where Deviation > 0.25
      | extend UserIdName = tostring(split(UserId, '@')[0]), UserIdUPNSuffix = tostring(split(UserId, '@')[1])
      | project-reorder StartTime, EndTime, UserAgent, UserAgentSeenCount, UserId, ClientIp, Site_Url
      | order by UserAgentSeenCount desc, UserAgent asc, UserId asc, Site_Url asc  
kind: Scheduled
name: Office 365 - SharePointFileOperation via devices with previously unseen user agents
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Global Secure Access/Analytic Rules/Office 365 - SharePoint_Downloads_byNewUserAgent.yaml
description: |
    Identifies anomalies if the number of documents uploaded or downloaded from device(s) associated with a previously unseen user agent exceeds a threshold (default is 5) and deviation (default is 25%).
status: Available

ARM

{
  "$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/efd17c5f-5167-40f8-a1e9-0818940785d9')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/efd17c5f-5167-40f8-a1e9-0818940785d9')]",
      "properties": {
        "alertRuleTemplateName": "efd17c5f-5167-40f8-a1e9-0818940785d9",
        "customDetails": null,
        "description": "Identifies anomalies if the number of documents uploaded or downloaded from device(s) associated with a previously unseen user agent exceeds a threshold (default is 5) and deviation (default is 25%).\n",
        "displayName": "Office 365 - SharePointFileOperation via devices with previously unseen user agents",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "UserId",
                "identifier": "FullName"
              },
              {
                "columnName": "UserIdName",
                "identifier": "Name"
              },
              {
                "columnName": "UserIdUPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "ClientIp",
                "identifier": "Address"
              }
            ]
          },
          {
            "entityType": "URL",
            "fieldMappings": [
              {
                "columnName": "Site_Url",
                "identifier": "Url"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Global Secure Access/Analytic Rules/Office 365 - SharePoint_Downloads_byNewUserAgent.yaml",
        "query": "// Set threshold for the number of downloads/uploads from a new user agent\nlet threshold = 5;\n// Define constants for SharePoint file operations\nlet szSharePointFileOperation = \"SharePointFileOperation\";\nlet szOperations = dynamic([\"FileDownloaded\", \"FileUploaded\"]);\n// Define the historical activity for analysis\nlet starttime = 14d; // Define the start time for historical data (14 days ago)\nlet endtime = 1d;   // Define the end time for historical data (1 day ago)\n// Extract the base events for analysis\nlet Baseevents =\n    EnrichedMicrosoft365AuditLogs\n    | where TimeGenerated between (ago(starttime) .. ago(endtime))\n    | where RecordType == szSharePointFileOperation\n    | where Operation in (szOperations)\n    | extend UserAgent = tostring(parse_json(tostring(AdditionalProperties)).UserAgent)\n    | extend Site_Url = tostring(parse_json(tostring(AdditionalProperties)).SiteUrl)\n    | where isnotempty(UserAgent);\n// Identify frequently occurring user agents\nlet FrequentUA = Baseevents\n    | summarize FUACount = count() by UserAgent, RecordType, Operation\n    | where FUACount >= threshold\n    | distinct UserAgent;\n// Calculate a user baseline for further analysis\nlet UserBaseLine = Baseevents\n    | summarize Count = count() by UserId, Operation, Site_Url\n    | summarize AvgCount = avg(Count) by UserId, Operation, Site_Url;\n// Extract recent activity for analysis\nlet RecentActivity = EnrichedMicrosoft365AuditLogs\n    | where TimeGenerated > ago(endtime)\n    | where RecordType == szSharePointFileOperation\n    | where Operation in (szOperations)\n    | extend UserAgent = tostring(parse_json(tostring(AdditionalProperties)).UserAgent)\n    | extend Site_Url = tostring(parse_json(tostring(AdditionalProperties)).SiteUrl)\n    | where isnotempty(UserAgent)\n    | where UserAgent in (FrequentUA)\n    | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), ObjectIdCount = dcount(ObjectId), ObjectIdList = make_set(ObjectId), UserAgentSeenCount = count()\n    by RecordType, Operation, UserAgent, UserId, ClientIp, Site_Url;\n// Analyze user behavior based on baseline and recent activity\nlet UserBehaviorAnalysis = UserBaseLine\n    | join kind=inner (RecentActivity) on UserId, Operation, Site_Url\n    | extend Deviation = abs(UserAgentSeenCount - AvgCount) / AvgCount;\n// Filter and format results for specific user behavior analysis\nUserBehaviorAnalysis\n    | where Deviation > 0.25\n    | extend UserIdName = tostring(split(UserId, '@')[0]), UserIdUPNSuffix = tostring(split(UserId, '@')[1])\n    | project-reorder StartTime, EndTime, UserAgent, UserAgentSeenCount, UserId, ClientIp, Site_Url\n    | order by UserAgentSeenCount desc, UserAgent asc, UserId asc, Site_Url asc\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Exfiltration"
        ],
        "techniques": [
          "T1030"
        ],
        "templateVersion": "2.2.5",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}