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Description

The following analytic identifies an Azure AD account with concurrent sessions coming from more than one unique Ip address within the span of 5 minutes. This behavior could represent a session hijacking attack whereby an adversary has extracted cookies from a victims browser and is using them from a different location to access corporate online resources. As users may behave differently across organizations, security teams should test and customize this detection to fit their environments.

  • Type: TTP

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2023-12-20
  • Author: Mauricio Velazco, Splunk
  • ID: a9126f73-9a9b-493d-96ec-0dd06695490d

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1185 Browser Session Hijacking Collection
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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 `azure_monitor_aad` properties.authenticationDetails{}.succeeded=true category=NonInteractiveUserSignInLogs 
| rename properties.* as * 
| bucket span=30m _time 
| stats count min(_time) as firstTime max(_time) as lastTime dc(src_ip) AS unique_ips values(src_ip) as src_ip values(appDisplayName) as appDisplayName by user 
| where unique_ips  > 1 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `azure_ad_concurrent_sessions_from_different_ips_filter`

Macros

The SPL above uses the following Macros:

:information_source: azure_ad_concurrent_sessions_from_different_ips_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • properties.status.errorCode
  • category
  • properties.authenticationDetails
  • user
  • src_ip

How To Implement

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 SignInLogs log category.

Known False Positives

A user with concurrent sessions 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

RBA

Risk Score Impact Confidence Message
42.0 70 60 User $user$ has concurrent sessions from more than one unique IP address in the span of 5 minutes.

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

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 | version: 2