The following analytic identifies the registration of a new Multi Factor authentication method for an AWS account. Adversaries who have obtained unauthorized access to an AWS account may register a new MFA method to maintain persistence.
- Type: TTP
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2023-01-31
- Author: Bhavin Patel, Splunk
- ID: 4e3c26f2-4fb9-4bd7-ab46-1b76ffa2a23b
Kill Chain Phase
- CIS 10
1 2 3 4 5 `cloudtrail` eventName=CreateVirtualMFADevice | stats count values(requestParameters.virtualMFADeviceName) as virtualMFADeviceName min(_time) as firstTime max(_time) as lastTime by eventSource aws_account_id errorCode userAgent eventID awsRegion userIdentity.principalId user_arn src_ip | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `aws_new_mfa_method_registered_for_user_filter`
The SPL above uses the following Macros:
aws_new_mfa_method_registered_for_user_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
You must install Splunk AWS add on and Splunk App for AWS. This search works when AWS CloudTrail logs.
Known False Positives
Newly onboarded users who are registering an MFA method for the first time will also trigger this detection.
Associated Analytic Story
|64.0||80||80||A new virtual device $virtualMFADeviceName$ is added to user $user_arn$|
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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