User Risk and MFA Registration Policy Updated

Status: test
Severity: high
Log source: product azure, service auditlogs
Author: Harjot Singh (@cyb3rjy0t)
Source: github.com/SigmaHQ/sigma

Detects changes and updates to the user risk and MFA registration policy. Attackers can modified the policies to Bypass MFA, weaken security thresholds, facilitate further attacks, maintain persistence.

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	No specific technique

Event coverage

Provider	Event
Entra-AuditLogs	Update User Risk and MFA Registration Policy

Rules detecting the same action

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

Azure Policy Violation Detected (Panther)
Changes to Device Registration Policy (Sigma)

Rule body yaml

title: User Risk and MFA Registration Policy Updated
id: d4c7758e-9417-4f2e-9109-6125d66dabef
status: test
description: |
    Detects changes and updates to the user risk and MFA registration policy.
    Attackers can modified the policies to Bypass MFA, weaken security thresholds, facilitate further attacks, maintain persistence.
references:
    - https://learn.microsoft.com/en-us/entra/id-protection/howto-identity-protection-configure-mfa-policy
    - https://learn.microsoft.com/en-us/entra/identity/monitoring-health/reference-audit-activities
author: Harjot Singh (@cyb3rjy0t)
date: 2024-08-13
tags:
    - attack.persistence
logsource:
    product: azure
    service: auditlogs
detection:
    selection:
        LoggedByService: 'AAD Management UX'
        Category: 'Policy'
        OperationName: 'Update User Risk and MFA Registration Policy'
    condition: selection
falsepositives:
    - Known updates by administrators.
level: high

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    LoggedByService: 'AAD Management UX'
    Category: 'Policy'
    OperationName: 'Update User Risk and MFA Registration Policy'

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
`Category`	eq	`Policy`
`LoggedByService`	eq	`AAD Management UX`
`OperationName`	eq	`Update User Risk and MFA Registration Policy`

`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)

User Risk and MFA Registration Policy Updated

MITRE ATT&CK coverage

Event coverage

Rules detecting the same action

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection`

Indicators

Keyboard shortcuts

Search operators

User Risk and MFA Registration Policy Updated

MITRE ATT&CK coverage

Event coverage

Rules detecting the same action

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection

Indicators

Stage 0: `condition`

Stage 1: `selection`