THIS IS A DEPRECATED DETECTION
This detection has been marked deprecated by the Splunk Threat Research team. This means that it will no longer be maintained or supported.
This search looks for AWS CloudTrail events where a user logged into the AWS account, is making API calls and has not enabled Multi Factor authentication. Multi factor authentication adds a layer of security by forcing the users to type a unique authentication code from an approved authentication device when they access AWS websites or services. AWS Best Practices recommend that you enable MFA for privileged IAM users.
- Type: Hunting
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2018-05-17
- Author: Bhavin Patel, Splunk
- ID: 4d46e8bd-4072-48e4-92db-0325889ef894
Kill Chain Phase
- CIS 16
1 2 3 4 5 6 7 8 9 `cloudtrail` userIdentity.sessionContext.attributes.mfaAuthenticated=false | search NOT [ | inputlookup aws_service_accounts | fields identity | rename identity as user] | stats count min(_time) as firstTime max(_time) as lastTime values(eventName) as eventName by userIdentity.arn userIdentity.type user | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `detect_api_activity_from_users_without_mfa_filter`
The SPL above uses the following Macros:
detect_api_activity_from_users_without_mfa_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
The SPL above uses the following Lookups:
List of fields required to use this analytic.
How To Implement
You must install the AWS App for Splunk (version 5.1.0 or later) and Splunk Add-on for AWS (version 4.4.0 or later), then configure your AWS CloudTrail inputs. Leverage the support search
Create a list of approved AWS service accounts: run it once every 30 days to create a list of service accounts and validate them.
This search produces fields (
userIdentity.arn) that are not yet supported by ES Incident Review and therefore cannot be viewed when a notable event is raised. These fields contribute additional context to the notable. To see the additional metadata, add the following fields, if not already present, to Incident Review - Event Attributes (Configure > Incident Management > Incident Review Settings > Add New Entry):\n1. Label: AWS Event Name, Field: eventName\
- Label: AWS User ARN, Field: userIdentity.arn\
Label: AWS User Type, Field: userIdentity.type
Detailed documentation on how to create a new field within Incident Review may be found here:
Known False Positives
Many service accounts configured within an AWS infrastructure do not have multi factor authentication enabled. Please ignore the service accounts, if triggered and instead add them to the aws_service_accounts.csv file to fine tune the detection. It is also possible that the search detects users in your environment using Single Sign-On systems, since the MFA is not handled by AWS.
Associated Analytic Story
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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