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Description

The following analytic detects an AWS account successfully authenticating from multiple unique IP addresses within a 5-minute window. It leverages AWS CloudTrail logs, specifically monitoring ConsoleLogin events and counting distinct source IPs. This behavior is significant as it may indicate compromised credentials, potentially from a phishing attack, being used concurrently by an adversary and a legitimate user. If confirmed malicious, this activity could allow unauthorized access to corporate resources, leading to data breaches or further exploitation within the AWS environment.

  • Type: Anomaly

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

  • Last Updated: 2024-05-26
  • Author: Bhavin Patel, Splunk
  • ID: 395e50e1-2b87-4fa3-8632-0dfbdcbcd2cb

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1586 Compromise Accounts Resource Development
T1535 Unused/Unsupported Cloud Regions Defense Evasion
Kill Chain Phase
  • Weaponization
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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 `cloudtrail` eventName = ConsoleLogin 
| bin span=5m _time 
| stats values(userAgent) as userAgent values(eventName) as eventName values(src_ip) as src_ip dc(src_ip) as distinct_ip_count by _time user_arn 
| where distinct_ip_count>1 
| `aws_successful_console_authentication_from_multiple_ips_filter`

Macros

The SPL above uses the following Macros:

:information_source: aws_successful_console_authentication_from_multiple_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
  • eventName
  • userAgent
  • src_ip
  • user_arn

How To Implement

You must install Splunk AWS add on and Splunk App for AWS. This search works when AWS CloudTrail events are normalized use the Authentication datamodel.

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

RBA

Risk Score Impact Confidence Message
72.0 90 80 User $user_arn$ has successfully logged into the AWS Console from different IP addresses $src_ip$ within 5 mins

: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: 3