ID | Technique | Tactic |
---|---|---|
T1586 | Compromise Accounts | Resource Development |
T1586.003 | Cloud Accounts | Resource Development |
T1110 | Brute Force | Credential Access |
T1110.003 | Password Spraying | Credential Access |
T1110.004 | Credential Stuffing | Credential Access |
Detection: AWS Unusual Number of Failed Authentications From Ip
Description
The following analytic identifies a single source IP failing to authenticate into the AWS Console with multiple valid users. It uses CloudTrail logs and calculates the standard deviation for source IP, leveraging the 3-sigma rule to detect unusual numbers of failed authentication attempts. This behavior is significant as it may indicate a Password Spraying attack, where an adversary attempts to gain initial access or elevate privileges. If confirmed malicious, this activity could lead to unauthorized access, data breaches, or further exploitation within the AWS environment.
Search
1`cloudtrail` eventName=ConsoleLogin action=failure
2| bucket span=10m _time
3| stats dc(_raw) AS distinct_attempts values(user_name) as tried_accounts by _time, src_ip
4| eventstats avg(distinct_attempts) as avg_attempts , stdev(distinct_attempts) as ip_std by _time
5| eval upperBound=(avg_attempts+ip_std*3)
6| eval isOutlier=if(distinct_attempts > 10 and distinct_attempts >= upperBound, 1, 0)
7| where isOutlier = 1
8|`aws_unusual_number_of_failed_authentications_from_ip_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
AWS CloudTrail ConsoleLogin | AWS | 'aws:cloudtrail' |
'aws_cloudtrail' |
N/A |
Macros Used
Name | Value |
---|---|
cloudtrail | sourcetype=aws:cloudtrail |
aws_unusual_number_of_failed_authentications_from_ip_filter | search * |
aws_unusual_number_of_failed_authentications_from_ip_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
Default Configuration
This detection is configured by default in Splunk Enterprise Security to run with the following settings:
Setting | Value |
---|---|
Disabled | true |
Cron Schedule | 0 * * * * |
Earliest Time | -70m@m |
Latest Time | -10m@m |
Schedule Window | auto |
Creates Risk Event | True |
Implementation
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 calculation of the upperBound field 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
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
Unusual number of failed console login attempts (Count: $distinct_attempts$) against users from IP Address - $src_ip$ | 54 | 60 | 90 |
References
Detection Testing
Test Type | Status | Dataset | Source | Sourcetype |
---|---|---|---|---|
Validation | ✅ Passing | N/A | N/A | N/A |
Unit | ✅ Passing | Dataset | aws_cloudtrail |
aws:cloudtrail |
Integration | ✅ Passing | Dataset | aws_cloudtrail |
aws:cloudtrail |
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: 3