SharePointFileOperation via devices with previously unseen user agents

Status: available
Severity: medium
Time window: 14d
Group by: Operation, Site_Url, UserId
Source: github.com/Azure/Azure-Sentinel

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).

MITRE ATT&CK coverage

Tactic	Techniques
Exfiltration	`T1030` Data Transfer Size Limits

Event coverage

Provider	Event
M365-SharePointFileOperation	FileDownloaded
M365-SharePointFileOperation	FileUploaded

Rules detecting the same action

Other rules on this platform that filter on the same API call or operation.

Hunt for Non-Anonymous Office 365 file downloads (YARA-L)
New executable via Office FileUploaded Operation (Kusto)
O365 OneDrive Anonymous File Downloaded (YARA-L)
SharePointFileOperation via previously unseen IPs (Kusto)

Rule body kusto

id: 5dd76a87-9f87-4576-bab3-268b0e2b338b
name: 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
status: Available
requiredDataConnectors:
  - connectorId: Office365
    dataTypes:
      - OfficeActivity
queryFrequency: 1d
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Exfiltration
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 =
    OfficeActivity
    | where TimeGenerated between (ago(starttime) .. ago(endtime))
    | where RecordType =~ szSharePointFileOperation
    | where Operation in~ (szOperations)
    | 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 = OfficeActivity
    | where TimeGenerated > ago(endtime)
    | where RecordType =~ szSharePointFileOperation
    | where Operation in~ (szOperations)
    | where isnotempty(UserAgent)
    | where UserAgent in~ (FrequentUA)
    | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), OfficeObjectIdCount = dcount(OfficeObjectId), OfficeObjectIdList = make_set(OfficeObjectId), UserAgentSeenCount = count() 
    by RecordType, Operation, UserAgent, UserType, UserId, ClientIP, OfficeWorkload, 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 > 25
    | extend UserIdName = tostring(split(UserId, '@')[0]), UserIdUPNSuffix = tostring(split(UserId, '@')[1])
    | project-reorder StartTime, EndTime, UserAgent, UserAgentSeenCount, UserId, ClientIP, Site_Url
    | project-away Site_Url1, UserId1, Operation1
    | order by UserAgentSeenCount desc, UserAgent asc, UserId asc, Site_Url asc
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: UserId
      - identifier: Name
        columnName: UserIdName
      - identifier: UPNSuffix
        columnName: UserIdUPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: ClientIP
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: Site_Url
version: 2.2.4
kind: Scheduled

Stages and Predicates

Parameters

let threshold = 5;
let szSharePointFileOperation = "SharePointFileOperation";
let szOperations = dynamic(["FileDownloaded", "FileUploaded"]);
let starttime = 14d;
let endtime = 1d;

Let binding: `FrequentUA`

let FrequentUA = Baseevents
  | summarize FUACount = count() by UserAgent, RecordType, Operation
  | where FUACount >= threshold
  | distinct UserAgent;

Derived from threshold, Baseevents.

Let binding: `RecentActivity`

let RecentActivity = OfficeActivity
  | where TimeGenerated > ago(endtime)
  | where RecordType =~ szSharePointFileOperation
  | where Operation in~ (szOperations)
  | where isnotempty(UserAgent)
  | where UserAgent in~ (FrequentUA)
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), OfficeObjectIdCount = dcount(OfficeObjectId), OfficeObjectIdList = make_set(OfficeObjectId), UserAgentSeenCount = count() 
  by RecordType, Operation, UserAgent, UserType, UserId, ClientIP, OfficeWorkload, Site_Url;

Derived from szSharePointFileOperation, szOperations, endtime, FrequentUA.

The stages below define let UserBehaviorAnalysis (the rule's main pipeline source).

Stage 1: `source`

OfficeActivity

Stage 2: `where`

| where TimeGenerated between (ago(starttime) .. ago(endtime))

Stage 3: `where`

| where RecordType =~ szSharePointFileOperation

Stage 4: `where`

| where Operation in~ (szOperations)

Stage 5: `where`

| where isnotempty(UserAgent)

Stage 6: `summarize`

| summarize Count = count() by UserId, Operation, Site_Url

Stage 7: `summarize`

| summarize AvgCount = avg(Count) by UserId, Operation, Site_Url

Stage 8: `join`

| join kind=inner (RecentActivity) on UserId, Operation, Site_Url

Stage 9: `extend`

| extend Deviation = abs(UserAgentSeenCount - AvgCount) / AvgCount

The stages below run on UserBehaviorAnalysis (the outer pipeline).

Stage 10: `where`

UserBehaviorAnalysis
| where Deviation > 25

Stage 11: `extend`

| extend UserIdName = tostring(split(UserId, '@')[0]), UserIdUPNSuffix = tostring(split(UserId, '@')[1])

Stage 12: `project-reorder`

| project-reorder StartTime, EndTime, UserAgent, UserAgentSeenCount, UserId, ClientIP, Site_Url

Stage 13: `project-away`

| project-away Site_Url1, UserId1, Operation1

Stage 14: `sort`

| order by UserAgentSeenCount desc, UserAgent asc, UserId asc, Site_Url asc

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`Deviation`	gt	`25` transforms: `cased`
`Operation`	in	`FileDownloaded` `FileUploaded`
`RecordType`	eq	`SharePointFileOperation`
`UserAgent`	in	`FrequentUA`
`UserAgent`	is_not_null	(no value, null check)

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

Field	Source
`AvgCount`	`summarize`
`Operation`	`summarize`
`Site_Url`	`summarize`
`UserId`	`summarize`
`Deviation`	`extend`
`UserIdName`	`extend`
`UserIdUPNSuffix`	`extend`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

SharePointFileOperation via devices with previously unseen user agents

MITRE ATT&CK coverage

Event coverage

Rules detecting the same action

Rule body kusto

Stages and Predicates

Parameters

Let binding: `FrequentUA`

Let binding: `RecentActivity`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `where`

Stage 5: `where`

Stage 6: `summarize`

Stage 7: `summarize`

Stage 8: `join`

Stage 9: `extend`

Stage 10: `where`

Stage 11: `extend`

Stage 12: `project-reorder`

Stage 13: `project-away`

Stage 14: `sort`

Indicators

Output fields

Keyboard shortcuts

Search operators

SharePointFileOperation via devices with previously unseen user agents

MITRE ATT&CK coverage

Event coverage

Rules detecting the same action

Rule body kusto

Stages and Predicates

Parameters

Let binding: FrequentUA

Let binding: RecentActivity

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: where

Stage 5: where

Stage 6: summarize

Stage 7: summarize

Stage 8: join

Stage 9: extend

Stage 10: where

Stage 11: extend

Stage 12: project-reorder

Stage 13: project-away

Stage 14: sort

Indicators

Output fields

Let binding: `FrequentUA`

Let binding: `RecentActivity`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `where`

Stage 5: `where`

Stage 6: `summarize`

Stage 7: `summarize`

Stage 8: `join`

Stage 9: `extend`

Stage 10: `where`

Stage 11: `extend`

Stage 12: `project-reorder`

Stage 13: `project-away`

Stage 14: `sort`