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Comment by Galanwe | Hacker News Reader

> is there any practical mechanism by which not using the VPC endpoints can be insecure,

Hum, yes. If you're not using VPC endpoints, basically you're routing all your AWS traffic to the open internet.

Not only is it wasteful and slow, but that also means you have to open free lunch internet egress on your instances, or implement some convoluted DNS based firewalling.

Using VPC endpoints also allows you to capture AWS service traffic and apply policy on it, such as whitelisting which buckets are accessible, thus avoiding internal data leaks.

Honestly there is just no argument for _not_ using VPC endpoints. Even on a purely architectural point of view, having you AWS traffic being routed out to internet just to get back in makes no sense.

If you are still unconvinced, the pricing argument of course still stands.

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> If you're not using VPC endpoints, basically you're routing all your AWS traffic to the open internet.

yes this is what i normally hear. but by “the open internet” you mean “some other spot in the AWS data center”. what’s the risk here? somebody is going to slip some bad routes into AWS over BGP? and then also fake the SSL certs? this seems like some mission impossible stuff.

> Honestly there is just no argument for _not_ using VPC endpoints.

unless something has changed in the last three months they’re not available for all services. would you advocate against using those services?

> If you are still unconvinced, the pricing argument of course still stands.

sure that and the exfiltration argument are reasonable enough.

thanks for response

> some other spot in the AWS data center

Well I can only guess so much of the underlying egress internet routing of AWS. At worst, if no explicit region is specified, it will reach the global aws endpoint through internet which is likely in a complete different part of the world than where you are, redirect to the local endpoint, and back.

> what’s the risk here?

Minimal, though I'm not sure the question is really relevant.

It's a bit as if you design a house with no internal doors, and you have to get out the window and back through the front door whenever you want to change room. I guess that wouldn't make you house less safe, though it's definitely a design that smells weird.

There is a real security point to make on the fact that it forces you to open access to egress internet though, and that is not to be taken lightly. There is no reason to allow a server full egress internet, and accessing AWS through internet basically forces you to do so, or leaves you implementing DNS based firewalling which is error prone, less secure, and overall a pain to setup.

> unless something has changed in the last three months they’re not available for all services. would you advocate against using those services?

No. Though I would (and do) strongly recommend implementing either DNS based firewalling, or a dynamic ruleset based on AWS ip ranges (they publish it as JSON).

> Well I can only guess so much of the underlying egress internet routing of AWS.

> At worst, if no explicit region is specified, it will reach the global aws endpoint through internet which is likely in a complete different part of the world than where you are, redirect to the local endpoint, and back.

There's no need to guess:

From https://aws.amazon.com/vpc/faqs/#Peering_Connections

"When using public IP addresses, all communication between instances and services hosted in AWS use AWS's private network. Packets that originate from the AWS network with a destination on the AWS network stay on the AWS global network, except traffic to or from AWS China Regions."

In practice there is not much risk from accessing AWS services using public endpoints, you just need to take AWS at their word.

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