SharePointFileOperation via devices with previously unseen user agents

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Id	5dd76a87-9f87-4576-bab3-268b0e2b338b
Rulename	SharePointFileOperation via devices with previously unseen user agents
Description	Identifies if the number of documents uploaded or downloaded from device(s) associated with a previously unseen user agent exceeds a threshold (default is 5).
Severity	Medium
Tactics	Exfiltration
Techniques	T1030
Required data connectors	Office365
Kind	Scheduled
Query frequency	1d
Query period	8d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft 365/Analytic Rules/SharePoint_Downloads_byNewUserAgent.yaml
Version	2.2.0
Arm template	5dd76a87-9f87-4576-bab3-268b0e2b338b.json

KQL

let threshold = 5;
let szSharePointFileOperation = "SharePointFileOperation";
let szOperations = dynamic(["FileDownloaded", "FileUploaded"]);
let starttime = 8d;
let endtime = 1d;
let historicalActivity =
OfficeActivity
| where TimeGenerated between(ago(starttime)..ago(endtime))
| where RecordType =~ szSharePointFileOperation
| where Operation in~ (szOperations)
| where isnotempty(UserAgent)
| summarize historicalCount = count() by UserAgent, RecordType, Operation;
let recentActivity = OfficeActivity
| where TimeGenerated > ago(endtime)
| where RecordType =~ szSharePointFileOperation
| where Operation in~ (szOperations)
| where isnotempty(UserAgent)
| summarize recentCount = count() by UserAgent, RecordType, Operation;
let RareUserAgent = recentActivity | join kind = leftanti (historicalActivity) on UserAgent
| order by recentCount desc, UserAgent
// More than 5 downloads/uploads from a new user agent today
| where recentCount > threshold;
OfficeActivity
| where TimeGenerated > ago(endtime)
| where RecordType =~ szSharePointFileOperation
| where Operation in~ (szOperations)
| where isnotempty(UserAgent)
| join kind= inner (RareUserAgent)
on UserAgent, RecordType, Operation
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), OfficeObjectIdCount = dcount(OfficeObjectId), OfficeObjectIdList = make_set(OfficeObjectId) 
by RecordType, Operation, UserAgent, UserType, UserId, ClientIP, OfficeWorkload, Site_Url, UserAgentSeenCount = recentCount
| 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: 8d
version: 2.2.0
relevantTechniques:
- T1030
queryFrequency: 1d
kind: Scheduled
name: SharePointFileOperation via devices with previously unseen user agents
id: 5dd76a87-9f87-4576-bab3-268b0e2b338b
entityMappings:
- fieldMappings:
  - columnName: UserIdName
    identifier: Name
  - columnName: UserIdName
    identifier: UPNSuffix
  entityType: Account
- fieldMappings:
  - columnName: ClientIP
    identifier: Address
  entityType: IP
- fieldMappings:
  - columnName: Site_Url
    identifier: Url
  entityType: URL
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft 365/Analytic Rules/SharePoint_Downloads_byNewUserAgent.yaml
severity: Medium
query: |
  let threshold = 5;
  let szSharePointFileOperation = "SharePointFileOperation";
  let szOperations = dynamic(["FileDownloaded", "FileUploaded"]);
  let starttime = 8d;
  let endtime = 1d;
  let historicalActivity =
  OfficeActivity
  | where TimeGenerated between(ago(starttime)..ago(endtime))
  | where RecordType =~ szSharePointFileOperation
  | where Operation in~ (szOperations)
  | where isnotempty(UserAgent)
  | summarize historicalCount = count() by UserAgent, RecordType, Operation;
  let recentActivity = OfficeActivity
  | where TimeGenerated > ago(endtime)
  | where RecordType =~ szSharePointFileOperation
  | where Operation in~ (szOperations)
  | where isnotempty(UserAgent)
  | summarize recentCount = count() by UserAgent, RecordType, Operation;
  let RareUserAgent = recentActivity | join kind = leftanti (historicalActivity) on UserAgent
  | order by recentCount desc, UserAgent
  // More than 5 downloads/uploads from a new user agent today
  | where recentCount > threshold;
  OfficeActivity
  | where TimeGenerated > ago(endtime)
  | where RecordType =~ szSharePointFileOperation
  | where Operation in~ (szOperations)
  | where isnotempty(UserAgent)
  | join kind= inner (RareUserAgent)
  on UserAgent, RecordType, Operation
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), OfficeObjectIdCount = dcount(OfficeObjectId), OfficeObjectIdList = make_set(OfficeObjectId) 
  by RecordType, Operation, UserAgent, UserType, UserId, ClientIP, OfficeWorkload, Site_Url, UserAgentSeenCount = recentCount
  | 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  
tactics:
- Exfiltration
description: |
  'Identifies if the number of documents uploaded or downloaded from device(s) associated
  with a previously unseen user agent exceeds a threshold (default is 5).'  
requiredDataConnectors:
- connectorId: Office365
  dataTypes:
  - OfficeActivity
status: Available
triggerThreshold: 0
triggerOperator: gt

ARM

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/5dd76a87-9f87-4576-bab3-268b0e2b338b')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/5dd76a87-9f87-4576-bab3-268b0e2b338b')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01",
      "properties": {
        "displayName": "SharePointFileOperation via devices with previously unseen user agents",
        "description": "'Identifies if the number of documents uploaded or downloaded from device(s) associated\nwith a previously unseen user agent exceeds a threshold (default is 5).'\n",
        "severity": "Medium",
        "enabled": true,
        "query": "let threshold = 5;\nlet szSharePointFileOperation = \"SharePointFileOperation\";\nlet szOperations = dynamic([\"FileDownloaded\", \"FileUploaded\"]);\nlet starttime = 8d;\nlet endtime = 1d;\nlet historicalActivity =\nOfficeActivity\n| where TimeGenerated between(ago(starttime)..ago(endtime))\n| where RecordType =~ szSharePointFileOperation\n| where Operation in~ (szOperations)\n| where isnotempty(UserAgent)\n| summarize historicalCount = count() by UserAgent, RecordType, Operation;\nlet recentActivity = OfficeActivity\n| where TimeGenerated > ago(endtime)\n| where RecordType =~ szSharePointFileOperation\n| where Operation in~ (szOperations)\n| where isnotempty(UserAgent)\n| summarize recentCount = count() by UserAgent, RecordType, Operation;\nlet RareUserAgent = recentActivity | join kind = leftanti (historicalActivity) on UserAgent\n| order by recentCount desc, UserAgent\n// More than 5 downloads/uploads from a new user agent today\n| where recentCount > threshold;\nOfficeActivity\n| where TimeGenerated > ago(endtime)\n| where RecordType =~ szSharePointFileOperation\n| where Operation in~ (szOperations)\n| where isnotempty(UserAgent)\n| join kind= inner (RareUserAgent)\non UserAgent, RecordType, Operation\n| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), OfficeObjectIdCount = dcount(OfficeObjectId), OfficeObjectIdList = make_set(OfficeObjectId) \nby RecordType, Operation, UserAgent, UserType, UserId, ClientIP, OfficeWorkload, Site_Url, UserAgentSeenCount = recentCount\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": "P8D",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Exfiltration"
        ],
        "techniques": [
          "T1030"
        ],
        "alertRuleTemplateName": "5dd76a87-9f87-4576-bab3-268b0e2b338b",
        "customDetails": null,
        "entityMappings": [
          {
            "fieldMappings": [
              {
                "identifier": "Name",
                "columnName": "UserIdName"
              },
              {
                "identifier": "UPNSuffix",
                "columnName": "UserIdName"
              }
            ],
            "entityType": "Account"
          },
          {
            "fieldMappings": [
              {
                "identifier": "Address",
                "columnName": "ClientIP"
              }
            ],
            "entityType": "IP"
          },
          {
            "fieldMappings": [
              {
                "identifier": "Url",
                "columnName": "Site_Url"
              }
            ],
            "entityType": "URL"
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft 365/Analytic Rules/SharePoint_Downloads_byNewUserAgent.yaml",
        "status": "Available",
        "templateVersion": "2.2.0"
      }
    }
  ]
}