PH_RULE_O365_AbnormalLogonDetected
Enabled
An Office 365 logon from this user was found to be abnormal based on historic baselines
9
Security
Resource Development
Resource Development consists of techniques that involve adversaries creating, purchasing, or compromising/stealing resources that can be used to support targeting. Such resources include infrastructure, accounts, or capabilities. These resources can be leveraged by the adversary to aid in other phases of the adversary lifecycle, such as using purchased domains to support Command and Control, email accounts for phishing as a part of Initial Access, or stealing code signing certificates to help with Defense Evasion.
https://attack.mitre.org/tactics/TA0042T1586.002
Compromise Accounts: Email Accounts
Before compromising a victim, adversaries may compromise email accounts that can be used during targeting. Adversaries can use compromised email accounts to further their operations, such as leveraging them to conduct Phishing. Utilizing an existing persona with a compromised email account may engender a level of trust in a potential victim if they have a relationship, or knowledge of, the compromised persona. Compromised email accounts can also be used in the acquisition of infrastructure
https://attack.mitre.org/techniques/T1586/002Network
Office 365 via Management Activity API
Correlation
Confirm why the user is logging in under suspicious circumstances. Investigate time, source, source country, user agent, method, and so on and confirm that user was intended to login via these methods.
If the following pattern or patterns match an ingested event within the given time window in seconds, trigger an incident.
300 seconds
If the following defined pattern/s occur within a 300 second time window.
abnormal_logon
This is the named definition of the event query, this is important if multiple subpatterns are defined to distinguish them.
This is the query logic that matches incoming events
eventType = "MS_OFFICE365_abnormal_o365_logon"
This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID
user,srcIpAddr
This is most typically a numerical constraint that defines when the rule should trigger an incident
COUNT(*) >= 1
This section defines which fields in matching raw events should be mapped to the incident attributes in the resulting incident.
The available raw event attributes to map are limited to the group by attributes and the aggregate event constraint fields for each subpattern
srcIpAddr=abnormal_logon.srcIpAddr,
user=abnormal_logon.user