Detection rules › Splunk

AWS Console Login Failed During MFA Challenge

Status
production
Severity
medium
Group by
"additionalEventData.MFAUsed", aws::awsRegion, aws::errorMessage, aws::recipientAccountId, aws::userAgent, dest, signature, src, user, vendor_product
Author
Bhavin Patel, Splunk
Source
github.com/splunk/security_content

The following analytic identifies failed authentication attempts to the AWS Console during the Multi-Factor Authentication (MFA) challenge. It leverages AWS CloudTrail logs, specifically the additionalEventData field, to detect when MFA was used but the login attempt still failed. This activity is significant as it may indicate an adversary attempting to access an account with compromised credentials but being thwarted by MFA. If confirmed malicious, this could suggest an ongoing attempt to breach the account, potentially leading to unauthorized access and further attacks if MFA is bypassed.

MITRE ATT&CK coverage

Rules detecting the same action

Other rules on this platform that filter on the same API call or operation.

Rule body splunk

name: AWS Console Login Failed During MFA Challenge
id: 55349868-5583-466f-98ab-d3beb321961e
version: 11
creation_date: '2022-10-03'
modification_date: '2026-05-13'
author: Bhavin Patel, Splunk
status: production
type: TTP
description: The following analytic identifies failed authentication attempts to the AWS Console during the Multi-Factor Authentication (MFA) challenge. It leverages AWS CloudTrail logs, specifically the `additionalEventData` field, to detect when MFA was used but the login attempt still failed. This activity is significant as it may indicate an adversary attempting to access an account with compromised credentials but being thwarted by MFA. If confirmed malicious, this could suggest an ongoing attempt to breach the account, potentially leading to unauthorized access and further attacks if MFA is bypassed.
data_source:
    - AWS CloudTrail ConsoleLogin
search: |-
    `cloudtrail` eventName= ConsoleLogin errorMessage="Failed authentication" additionalEventData.MFAUsed = "Yes"
      | rename user_name as user
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY signature dest user
           user_agent src vendor_account
           vendor_region vendor_product additionalEventData.MFAUsed
           errorMessage
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `aws_console_login_failed_during_mfa_challenge_filter`
how_to_implement: The Splunk AWS Add-on is required to utilize this data. The search requires AWS CloudTrail logs.
known_false_positives: Legitimate users may miss to reply the MFA challenge within the time window or deny it by mistake.
references:
    - https://attack.mitre.org/techniques/T1621/
    - https://aws.amazon.com/what-is/mfa/
drilldown_searches:
    - name: View the detection results for - "$user$"
      search: '%original_detection_search% | search  user = "$user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$user$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: User $user$ failed to pass MFA challenge while logging into console from $src$
    entity:
        field: user
        type: user
        score: 50
threat_objects:
    - field: src
      type: ip_address
analytic_story:
    - AWS Identity and Access Management Account Takeover
    - Compromised User Account
asset_type: AWS Account
mitre_attack_id:
    - T1586.003
    - T1621
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: cloud
security_domain: threat
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1621/aws_failed_mfa/cloudtrail.json
          sourcetype: aws:cloudtrail
          source: aws_cloudtrail
      test_type: unit

Stages and Predicates

Stage 1: search

`cloudtrail` eventName= ConsoleLogin errorMessage="Failed authentication" additionalEventData.MFAUsed = "Yes"

Stage 2: rename

| rename user_name as user

Stage 3: stats

| stats count min(_time) as firstTime max(_time) as lastTime
    BY signature dest user
       user_agent src vendor_account
       vendor_region vendor_product additionalEventData.MFAUsed
       errorMessage

Stage 4: search

| `security_content_ctime(firstTime)`

Stage 5: search

| `security_content_ctime(lastTime)`

Stage 6: search

| `aws_console_login_failed_during_mfa_challenge_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
additionalEventData.MFAUsedeq
  • "Yes"
errorMessageeq
  • "Failed authentication"
eventNameeq
  • ConsoleLogin
sourcetypeeq
  • aws:cloudtrail