cdn-securitygroup-sync

Automates sync of AWS security groups with your CDN provider's CIDRs - currently Akamai Siteshield and Cloudflare are supported. Does basically the same job as SSSG-Ninja (for Akamai) but...

comes as a single, ready-to-use, stand-alone binary
comes with a CloudFormation stack for simple deployment as a scheduled AWS Lambda function
has no hard-coded configuration data (like this or that)

build / install

go get -v github.com/schnoddelbotz/cdn-securitygroup-sync to build or grab a binary from the releases page.

CLI usage

Usage of cdn-securitygroup-sync:
  -acknowledge
      Acknowledge updated CIDRs on Akamai
  -add-missing
      Add missing CIDRs to AWS security group
  -cloudflare
      Use Cloudflare instead of Akamai
  -delete-obsolete
      Delete obsolete CIDRs from AWS security group
  -list-ss-ids
      List Akamai siteshield IDs and quit
  -sgid string
      AWS security group ID
  -ssid int
      Akamai siteshield ID

Security group (-sgid) can be specified via envrionment variable AWS_SECGROUP_ID, too. SiteShield ID (-ssid) can be alternatively provided via AKAMAI_SSID. Additionally, for Akamai, these specific API environment variables must be defined:

AKAMAI_EDGEGRID_HOST
AKAMAI_EDGEGRID_CLIENT_TOKEN
AKAMAI_EDGEGRID_CLIENT_SECRET
AKAMAI_EDGEGRID_ACCESS_TOKEN

By default, cdn-securitygroup-sync will only list missing and obsolete CIDRs. Arguments -add-missing, -delete-obsolete or -acknowledge have to be given explicitly to enable corresponding actions.

cdn-securitygroup-sync will create inbound rules on the given security group, with a port range of 80-443, originating from CDN CIDRs. Any rules not using the port range will remain untouched. You may rely on this behaviour for new ELB/security group deployments: Create them with an inbound rule of 0.0.0.0/32, port range 80-443; upon first cdn-securitygroup-sync invocation that rule will be removed and replaced by correct CDN CIDRs.

lambda deployment

The lambda approach assumes that you store runtime configuration and credentials in parameter store. To do so, create a KMS key and refer to that key during stack deployment, as outlined below. You will also have to provide a S3 bucket to store lambda code.

put required entries into EC2 parameter store

The stack will create an IAM role that is granted KMS key access. Parameter store entries will use a prefix (which defaults to css), which is used to restrict access to the entries and allows to deploy multiple, independent instances of the lambda.

Using AWS CLI or AWS console, put these "secure string" parameters into parameter store (assuming default prefix css in this example):

css_AWS_SECGROUP_ID: The AWS EC2 security group to keep in sync (sg-....)
css_CSS_ARGS: A comma-separated list of arguments for cdn-securitygroup-sync. Those arguments equal the command-line version of cdn-securitygroup-sync, i.e. to fully automate sync for Akamai, use -add-missing,-delete-obsolete,-acknowledge. To sync with Cloudflare (which doesn't require acknowledgement), use -add-missing,-delete-obsolete,-cloudflare.

If using Akamai, you will have to provide corresponding API credentials:

css_AKAMAI_SSID: The SiteShield ID; can be obtained by using -list-ss-ids argument
css_AKAMAI_EDGEGRID_HOST: Something like xxxxxxx.luna.akamaiapis.net
css_AKAMAI_EDGEGRID_CLIENT_TOKEN
css_AKAMAI_EDGEGRID_CLIENT_SECRET
css_AKAMAI_EDGEGRID_ACCESS_TOKEN

There's no need to store any AWS credentials: The stack will create a policy that grants the lambda required permissions to update the security group.

deploy the lambda handler

There are two options for lambda deployment: Grab a pre-built lambda handler .zip from the releases page and upload it to your S3 bucket OR build cdn-securitygroup-sync from source.

variant 1 - deploy a pre-built release

download the latest cdn-securitygroup-sync-lambda-....zip from releases page
upload the .zip to a S3 bucket (do not unzip!)
deploy the lambda function using cloudFormation stack, either via AWS console or by cloning this repository and running make:

make deploy-prebuilt AWS_REGION=eu-west-1 AWS_ACCOUNT_ID=123456... SSM_KEY_ID=abc-def \
        S3_BUCKET=my-little-bucket S3_KEY=path/to/cdn-securitygroup-sync-lambda-....zip

variant 2 - deploy from source

Build dependencies: AWS-CLI, Docker, Go 1.8+, Make.

make deploy-source AWS_REGION=eu-west-1 AWS_ACCOUNT_ID=123456... SSM_KEY_ID=abc-def \
        S3_BUCKET=my-little-bucket

To just build and upload the lambda .zip to your S3 bucket named my-little-bucket for later (variant 1) usage:

# S3 key / destination path defaults to 'code/cdn-securitygroup-sync-$(VERSION).zip'
make S3_BUCKET=my-little-bucket

license

MIT.

Use cdn-securitygroup-sync at your own risk!

This project includes these 3rd party libraries to do its job: