Suspicious Microsoft 365 UserLoggedIn via OAuth Code

Last updated a month ago on 2025-07-16
Created 4 months ago on 2025-05-01

About

Identifies sign-ins on behalf of a principal user to the Microsoft Graph API from multiple IPs using the Microsoft Authentication Broker or Visual Studio Code application. This behavior may indicate an adversary using a phished OAuth refresh token.
Tags
Domain: CloudDomain: EmailDomain: IdentityData Source: Microsoft 365Data Source: Microsoft 365 Audit LogsUse Case: Identity and Access AuditUse Case: Threat DetectionTactic: Defense EvasionLanguage: esql
Severity
high
Risk Score
73
MITRE ATT&CK™

Defense Evasion (TA0005)(opens in a new tab or window)

License
Elastic License v2(opens in a new tab or window)

Definition

Integration Pack
Prebuilt Security Detection Rules
Related Integrations

o365(opens in a new tab or window)

Query
from logs-o365.audit-*
| where
    event.dataset == "o365.audit" and
    event.action == "UserLoggedIn" and
    source.ip is not null and
    o365.audit.UserId is not null and
    o365.audit.ApplicationId is not null and
    o365.audit.UserType in ("0", "2", "3", "10") and
    o365.audit.ApplicationId in ("aebc6443-996d-45c2-90f0-388ff96faa56", "29d9ed98-a469-4536-ade2-f981bc1d605e") and
    o365.audit.ObjectId in ("00000003-0000-0000-c000-000000000000")
| eval
    Esql.time_window_date_trunc = date_trunc(30 minutes, @timestamp),
    Esql.oauth_authorize_user_id_case = case(
        o365.audit.ExtendedProperties.RequestType == "OAuth2:Authorize" and o365.audit.ExtendedProperties.ResultStatusDetail == "Redirect",
        o365.audit.UserId,
        null
    ),
    Esql.oauth_token_user_id_case = case(
        o365.audit.ExtendedProperties.RequestType == "OAuth2:Token",
        o365.audit.UserId,
        null
    )
| stats
    Esql.source_ip_count_distinct = count_distinct(source.ip),
    Esql.source_ip_values = values(source.ip),
    Esql.o365_audit_ApplicationId_values = values(o365.audit.ApplicationId),
    Esql.source_as_organization_name_values = values(source.`as`.organization.name),
    Esql.oauth_token_count_distinct = count_distinct(Esql.oauth_token_user_id_case),
    Esql.oauth_authorize_count_distinct = count_distinct(Esql.oauth_authorize_user_id_case)
  by
    o365.audit.UserId,
    Esql.time_window_date_trunc,
    o365.audit.ApplicationId,
    o365.audit.ObjectId
| keep
    Esql.time_window_date_trunc,
    Esql.source_ip_values,
    Esql.source_ip_count_distinct,
    Esql.o365_audit_ApplicationId_values,
    Esql.source_as_organization_name_values,
    Esql.oauth_token_count_distinct,
    Esql.oauth_authorize_count_distinct
| where
    Esql.source_ip_count_distinct >= 2 and
    Esql.oauth_token_count_distinct > 0 and
    Esql.oauth_authorize_count_distinct > 0

Install detection rules in Elastic Security

Detect Suspicious Microsoft 365 UserLoggedIn via OAuth Code in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).