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The parameters can be accessed using AWS CLI or one of the language specific AWS client libraries.

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Get encrypted parameter

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/NIIS/Test

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Code Block

# Get the whole parameter object $ aws ssm get-parameter --name "/NIIS/Test" --with-decryption --output json { "Parameter": { "Name": "/NIIS/Test", "Type": "SecureString", "Value": "MySecureString", "Version": 1, "Selector": "", "LastModifiedDate": 1562562294.084, "ARN": "arn:aws:ssm:region:account-id:parameter/NIIS/Test" } } # Get parameter value only $ aws ssm get-parameter --name "/NIIS/Test" --with-decryption --output json | jq -r '.Parameter.Value' MySecureString

Parameters can be stored plain text or encrypted. When encryption is used, it's possible to

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use the default KMS key for the account or specify a customer-managed CMK for this account. Either way, the user or service accessing the parameter must have sufficient permissions to access the encryption key and the parameter itself.

Note
Currenlty AWS CloudFormation doesn't support the SecureString parameter type. This means that encrypted parameters must be created manually or using an additional script - they cannot be created using CloudFormation. Read more.

The following IAM policy gives access to a specified parameter encrypted with the default KMS key for the account.

IAM Policy Example

{
   "Version":"2012-10-17",
   "Statement":[
      {
         "Effect":"Allow",
         "Action":[
            "ssm:GetParameter"
         ],
         "Resource":[
            "arn:aws:ssm:<region>:<account-id>:parameter/<parameter-name>"
         ]
      },
      {
         "Effect":"Allow",
         "Action":[
            "kms:Decrypt"
         ],
         "Resource":[
            "arn:aws:kms:<region>:<account-id>:key/alias/aws/ssm"
         ]
      }
   ]
}

CloudFormation Example

  SSInstance:
    Type: AWS::EC2::Instance
    Properties:
      .
      .
      IamInstanceProfile: !Ref XRdPlaygroundInstanceProfile
      .
      .
  XRdPlaygroundInstanceProfile:
    Type: AWS::IAM::InstanceProfile
    Properties:
      InstanceProfileName: String
      Path: /
      Roles:
        - !Ref XRdPlaygroundRole
  XRdPlaygroundRole:
    Type: 'AWS::IAM::Role'
    Properties:
      AssumeRolePolicyDocument:
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - ec2.amazonaws.com
            Action:
              - 'sts:AssumeRole'
      Path: /
      Policies:
        - PolicyName: PINCodePolicy
          PolicyDocument:
            Statement:
              - Effect: Allow
                Action:
                  - 'ssm:GetParameter'
                Resource:
                  - !Sub 'arn:aws:ssm:${AWS::Region}:${AWS::AccountId}:parameter/${SSMPINCodeParameterName}'
        - PolicyName: KMSKeyPolicy
          PolicyDocument:
            Statement:
              - Effect: Allow
                Action:
                  - 'kms:Decrypt'
                Resource:
                  - !Sub 'arn:aws:kms:${AWS::Region}:${AWS::AccountId}:key/alias/aws/ssm'

The above CloudFormation example uses inline policies, but customer managed policies could be used too.

Storing Security Server PIN Code in SSM

Security Server PIN code can be stored in SSM. In that case a custom bash script (/usr/share/xroad/autologin/custom-fetch-pin.sh) must be implemented according to the auto-login documentation. The script must fetch the PIN code from SSM and output the PIN code to stdout. AWS CLI and jq must be installed on the Security Server. Read more about installing the AWS CLI on Linux.

/usr/share/xroad/autologin/custom-fetch-pin.sh

#!/bin/bash
PIN_CODE=$(~/.local/bin/aws ssm get-parameter --name "<parameter-name>" --with-decryption --output json --region <region> | jq -r '.Parameter.Value')
echo "${PIN_CODE}"
exit 0

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