Detection: Azure AD Successful Authentication From Different Ips

Description

The following analytic detects an Azure AD account successfully authenticating from multiple unique IP addresses within a 30-minute window. It leverages Azure AD SignInLogs to identify instances where the same user logs in from different IPs in a short time frame. This behavior is significant as it may indicate compromised credentials being used by an adversary, potentially following a phishing attack. If confirmed malicious, this activity could allow unauthorized access to corporate resources, leading to data breaches or further exploitation within the network.

Search

 1`azure_monitor_aad` properties.authenticationDetails{}.succeeded=true category=SignInLogs
 2  
 3| rename properties.* as *
 4  
 5| bucket span=30m _time
 6  
 7| fillnull
 8  
 9| stats count min(_time) as firstTime max(_time) as lastTime dc(src) AS unique_ips values(dest) as dest values(src) as src
10    BY user vendor_account vendor_product
11       signature
12  
13| `security_content_ctime(firstTime)`
14  
15| `security_content_ctime(lastTime)`
16  
17| where unique_ips > 1
18  
19| `azure_ad_successful_authentication_from_different_ips_filter`

Data Source

Name	Platform	Sourcetype	Source
Azure Active Directory	Azure	'azure:monitor:aad'	'Azure AD'

Macros Used

Annotations

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Implementation

You must install the latest version of Splunk Add-on for Microsoft Cloud Services from Splunkbase (https://splunkbase.splunk.com/app/3110/#/details). You must be ingesting Azure Active Directory events into your Splunk environment through an EventHub. This analytic was written to be used with the azure:monitor:aad sourcetype leveraging the Signin log category.

Known False Positives

A user with successful authentication events from different Ips may also represent the legitimate use of more than one device. Filter as needed and/or customize the threshold to fit your environment.

Associated Analytic Story

• Azure Active Directory Account Takeover

• Compromised User Account

Finding

Threat Objects

References

• https://attack.mitre.org/techniques/T1110.003

• https://attack.mitre.org/techniques/T1110.001

• https://attack.mitre.org/techniques/T1110

Detection Testing

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 14