Office Policy Tampering

Status: available
Severity: medium
Time window: 1d
Group by: ClientIP, Operation, Parameters, Port, ResultStatus, UserId, UserType
Source: github.com/Azure/Azure-Sentinel

Identifies if any tampering is done to either auditlog, ATP Safelink, SafeAttachment, AntiPhish or Dlp policy. An adversary may use this technique to evade detection or avoid other policy based defenses. References: https://docs.microsoft.com/powershell/module/exchange/advanced-threat-protection/remove-antiphishrule?view=exchange-ps.

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1098` Account Manipulation
Stealth	`T1562` Impair Defenses

Event coverage

Provider	Event	Title
M365-ExchangeAdmin	_catch_all	Exchange admin activity (catch-all)

Rule body kusto

id: fbd72eb8-087e-466b-bd54-1ca6ea08c6d3
name: Office Policy Tampering
description: |
  'Identifies if any tampering is done to either auditlog, ATP Safelink, SafeAttachment, AntiPhish or Dlp policy. 
  An adversary may use this technique to evade detection or avoid other policy based defenses.
  References: https://docs.microsoft.com/powershell/module/exchange/advanced-threat-protection/remove-antiphishrule?view=exchange-ps.'
severity: Medium
status: Available 
requiredDataConnectors:
  - connectorId: Office365
    dataTypes:
      - OfficeActivity (Exchange)
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Persistence
  - DefenseEvasion
relevantTechniques:
  - T1098
  - T1562
query: |
  let opList = OfficeActivity 
  | summarize by Operation
  //| where Operation startswith "Remove-" or Operation startswith "Disable-"
  | where Operation has_any ("Remove", "Disable")
  | where Operation contains "AntiPhish" or Operation contains "SafeAttachment" or Operation contains "SafeLinks" or Operation contains "Dlp" or Operation contains "Audit"
  | summarize make_set(Operation, 500);
  OfficeActivity
  // Only admin or global-admin can disable/remove policy
  | where RecordType =~ "ExchangeAdmin"
  | where UserType in~ ("Admin","DcAdmin")
  // Pass in interesting Operation list
  | where Operation in~ (opList)
  | extend ClientIPOnly = case( 
  ClientIP has ".", tostring(split(ClientIP,":")[0]), 
  ClientIP has "[", tostring(trim_start(@'[[]',tostring(split(ClientIP,"]")[0]))),
  ClientIP
  )  
  | extend Port = case(
  ClientIP has ".", (split(ClientIP,":")[1]),
  ClientIP has "[", tostring(split(ClientIP,"]:")[1]),
  ClientIP
  )
  | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), OperationCount = count() by Operation, UserType, UserId, ClientIP = ClientIPOnly, Port, ResultStatus, Parameters
  | extend AccountName = tostring(split(UserId, "@")[0]), AccountUPNSuffix = tostring(split(UserId, "@")[1])
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: UserId
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: AccountUPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: ClientIP
version: 2.0.3
kind: Scheduled

Stages and Predicates

Let binding: `opList`

let opList = OfficeActivity 
| summarize by Operation
| where Operation has_any ("Remove", "Disable")
| where Operation contains "AntiPhish" or Operation contains "SafeAttachment" or Operation contains "SafeLinks" or Operation contains "Dlp" or Operation contains "Audit"
| summarize make_set(Operation, 500);

Stage 1: `source`

OfficeActivity

Stage 2: `where`

| where RecordType =~ "ExchangeAdmin"

Stage 3: `where`

| where UserType in~ ("Admin","DcAdmin")

Stage 4: `where`

| where Operation in~ (opList)

References opList (defined above).

Stage 5: `extend`

| extend ClientIPOnly = case( 
ClientIP has ".", tostring(split(ClientIP,":")[0]), 
ClientIP has "[", tostring(trim_start(@'[[]',tostring(split(ClientIP,"]")[0]))),
ClientIP
)

ClientIPOnly =

ifClientIP has "."tostring(split(ClientIP, ":")[0])

elifClientIP has "["tostring(trim_start(@'[[]', tostring(split(ClientIP, "]")[0])))

elseClientIP

Stage 6: `extend`

| extend Port = case(
ClientIP has ".", (split(ClientIP,":")[1]),
ClientIP has "[", tostring(split(ClientIP,"]:")[1]),
ClientIP
)

Port =

ifClientIP has "."split(ClientIP, ":")[1]

elifClientIP has "["tostring(split(ClientIP, "]:")[1])

elseClientIP

Stage 7: `summarize`

| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), OperationCount = count() by Operation, UserType, UserId, ClientIP = ClientIPOnly, Port, ResultStatus, Parameters

Stage 8: `extend`

| extend AccountName = tostring(split(UserId, "@")[0]), AccountUPNSuffix = tostring(split(UserId, "@")[1])

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
`Operation`	in	`opList`
`RecordType`	eq	`ExchangeAdmin`
`UserType`	in	`Admin` `DcAdmin`

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
`ClientIP`	`summarize`
`EndTimeUtc`	`summarize`
`Operation`	`summarize`
`OperationCount`	`summarize`
`Parameters`	`summarize`
`Port`	`summarize`
`ResultStatus`	`summarize`
`StartTimeUtc`	`summarize`
`UserId`	`summarize`
`UserType`	`summarize`
`AccountName`	`extend`
`AccountUPNSuffix`	`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)

Office Policy Tampering

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Let binding: `opList`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `where`

Stage 5: `extend`

Stage 6: `extend`

Stage 7: `summarize`

Stage 8: `extend`

Indicators

Output fields

Keyboard shortcuts

Search operators

Office Policy Tampering

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Let binding: opList

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: where

Stage 5: extend

Stage 6: extend

Stage 7: summarize

Stage 8: extend

Indicators

Output fields

Let binding: `opList`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `where`

Stage 5: `extend`

Stage 6: `extend`

Stage 7: `summarize`

Stage 8: `extend`