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Description

The following analytic identifies one source Ip failing to authenticate into the AWS Console with 30 unique valid users within 10 minutes. This behavior could represent an adversary performing a Password Spraying attack against an AWS environment tenant to obtain initial access or elevate privileges.

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

  • Last Updated: 2022-09-27
  • Author: Bhavin Patel
  • ID: 71e1fb89-dd5f-4691-8523-575420de4630

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1110 Brute Force Credential Access
T1110.003 Password Spraying Credential Access
T1110.004 Credential Stuffing Credential Access
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 3
  • CIS 5
  • CIS 16
CVE
1
2
3
4
5
`cloudtrail` eventName=ConsoleLogin action=failure 
| bucket span=10m _time 
| stats  dc(_raw) AS unique_accounts values(user_name) as tried_accounts by _time, src_ip, eventName, action, user_agent 
|  where unique_accounts > 30 
|`aws_unusual_number_of_failed_authentications_from_ip_filter`

Macros

The SPL above uses the following Macros:

:information_source: aws_multiple_users_failing_to_authenticate_from_ip_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
  • user
  • action
  • eventName
  • src_ip

How To Implement

You must install Splunk Add-on for AWS in order to ingest Cloudtrail. We recommend the users to try different combinations of the bucket span time and the tried account threshold to tune this search according to their environment.

Known False Positives

No known false postives for this detection. Please review this alert

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
54.0 60 90 Multiple failed console login attempts against users $tried_accounts$ seen from $src_ip$

: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: 1