AWS IAM Role that both services *and* Humans-with-2fa can assume

cloudformation.yml

AWSTemplateFormatVersion: '2010-09-09'
Resources:
    ExampleRole:
        Type: AWS::IAM::Role
        Properties:
          Path: "/cfn/"
          ManagedPolicyArns:
          - arn:aws:iam::aws:policy/AmazonS3ReadOnlyAccess
          Policies:
          - PolicyName: DynamoDBGetter
            PolicyDocument:
              Statement:
              - Effect: Allow
                Action:
                  - dynamodb:GetItem
                Resource:
                  - !Sub "arn:aws:dynamodb:${AWS::Region}:${AWS::AccountId}:table/specificTableName"
          AssumeRolePolicyDocument:
            Version: '2012-10-17'
            Statement:
            - Effect: Allow
              Sid: 'LambdaCanReadTable'
              Principal:
                Service:
                - lambda.amazonaws.com
              Action:
                - sts:AssumeRole
            - Effect: Allow
              Sid: 'HumanCanReadTableToo'
              Principal:
                AWS:
                - !Ref AWS::AccountId
              Action:
                - sts:AssumeRole
              Condition:
                Bool:
                  aws:MultiFactorAuthPresent: 'true'

    ExampleAdminRole:
        Type: AWS::IAM::Role
        Properties:
          Path: "/cfn/"
          ManagedPolicyArns:
          - arn:aws:iam::aws:policy/AmazonS3ReadOnlyAccess
          Policies:
          - PolicyName: DynamoDBAdmin
            PolicyDocument:
              Statement:
              - Effect: Allow
                Action:
                  - dynamodb:*
                Resource:
                  - !Sub "arn:aws:dynamodb:${AWS::Region}:${AWS::AccountId}:table/specificTableName"
          AssumeRolePolicyDocument:
            Version: '2012-10-17'
            Statement:
            - Effect: Allow
              Sid: 'HumanAdmin'
              Principal:
                AWS:
                - !Ref AWS::AccountId
              Action:
                - sts:AssumeRole
              Condition:
                Bool:
                  aws:MultiFactorAuthPresent: 'true'

This is a contrived example that shows two IAM Roles that allows:

• Any S3 Read Access
• A Specific DDB Table access

The first role allows dynamoddb:GetItem access on the table. Both lambda functions (where this role is applied) and Humans-with-2fa can assume this role.
The second role allows for "HumanAdmins" to do ANYTHING to the specific table. Only Humans-with-2fa can use this role.