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Exposing Databases to the Internet: Seriously?

One big piece of conventional wisdom for software operation is "never expose internal-facing services to the public", and databases (especially SQL databases) fall into that category. It's good advice because data stored in them are usually highly sensitive and indispensable to most systems' proper running. Investigations with honeypots showed that publicly open databases are discovered within hours after they become active and start getting attacked within a day. What's scarier than this is you often don't even know you ever had a data breach.

Database Region Time To First Connection (Hrs) Time To First Attack (Hrs) Attack Type
MySQL Frankfurt 8 10 Malware Deployment
MariaDB Tokyo 2 11 Massive Brute Force - multiple IPs
Aurora North Virginia 1 15 Malware Deployment
Postgres North Virginia 4 288 Malware Deployment
MySQL São Paulo 1/4 16 Massive Brute Force - multiple IPs
Postgres Frankfurt 6 240 Information Gathering: DB version and configuration

Data from Imperva.

Time To First Connection: hours until the database was found and connected

Time To First Attack: hours until the database got its first attack

But things have been changing gradually during the past decade. The rise of serverless computing made it easy to spin up remote database instances and consume them from over the internet. An obvious bad practice? It's more complicated than a simple yes/no answer.

Let's explore why this is happening, the different ways how it happens, and the risk implications.

What Drives the Desire for Publicly Accessible Databases?

Is conventional wisdom dead? Or are people now so reckless to push their products to the market ASAP without worrying much about data security? The reality is that security is always a trade-off and never black or white. Sometimes the perceived gain outweighs the higher risks that come with it. Let's look at some of the driving forces.

Architecture Choice

To NOT expose your database to the internet, you'll need to colocate your backend services with it (physically or virtually). From a security point of view, the responsibility of the backend services is to control access and limit the surface of exposure. Instead of opening up full CRUD operations, your APIs do that selectively and conditionally.

This is what people have been doing for decades. But with the rise of cloud computing, there's suddenly such an abundance of choices for computing and storage platforms, and you may not want to use the same vendor for both. Without a private network boundary, you'll need to expose your database to the public network.

Using Cloud-based Analytics Tools

Another force comes from the need to do flexible analytics. Databases are not only the foundation of your application but also the source of truth for your business analytics. Analysts love the power and autonomy offered by cloud-based BI tools like Tableau, PowerBI, etc., with which they can connect to the databases in seconds and start creating charts and dashboards right away. Apparently, read-only access to your database from the public internet is needed to make this work.

Two Ways of Exposing Your Database

Driver-level Direct Connectivity

The most straightforward way to open up your database to the internet is to allow drivers to connect directly. With a traditional virtual-machine based setup in cloud platforms like AWS or Azure, this means assigning a public IP address to the server and allowing inbound connection to the service port in the firewall (if any). However, with PaaS/Serverless database platforms, you usually get it set up for you immediately after an instance is created.

In such a configuration, by default, the only protection your database has is the password, so make sure a strong one is used. Depending on what the hoster supports, you should consider the following measures to reduce the chance of data breach:

  • Enable 2FA for admin access
  • Rotate database password regularly
  • Use separate credentials for different privileges
  • Set up IP whitelist
  • Allow only SSL connections
  • Encrypt data at rest
  • Make full backup regularly

Automatically Generated APIs

As running web workload becomes the prevailing use case of databases, some new-generation vendors have started to offer web-native solutions. To name a few:

They differ from traditional databases in several ways:

  1. Instead of using TCP protocol, use HTTP.
  2. Instead of using SQL, use GraphQL or RESTful APIs.
  3. Instead of serving a small number of long-running connections, design for a large number of short-lived ones.

Obviously, the goal is to turn a database into something that fits well into modern web architecture. Such databases are, by design, open to the web. They wrap an API layer around traditional database services, but the APIs essentially support full data access. Of course, you mustn't naively let all requests through; they're almost always integrated with an authentication system and require you to set up security policies to guard access.

This is very different from what people were used to: a naive database behind a carefully implemented secure backend service. In fact, there's no backend service anymore; the clients from the internet are meant to "manipulate" the database directly.

Scary as it sounds, this may be better than the traditional way in terms of security:

  • Modeling access policy at the database level is more robust than at the application level. You can often iterate your application without changing the security model.
  • The web API hides some dangerous power of the database, like making full dump, executing arbitrary SQL, loading and running remote code, etc.

The biggest challenge of this approach is to configure the access policies correctly. It takes work to get it right, and even harder to maintain over time.

Is The Future of Web Security Doomed?

This is a tricky question. The rule of "never expose your database to the public" was never achieved in the first place. As long as you have any public API that allows CRUD operations, you're already "exposing".

You may say I'm quibbling, but I wanted to make the point (again) that web security is always a trade-off. By moving to the cloud, we - including vendors and buyers, have already collectively traded off the security of our data for convenience and cost-effectiveness. Years ago, cloud companies struggled so badly to convince enterprises to embrace the cloud, but eventually, the invisible hands have made its influence.

For databases, different ways of challenging conventional wisdom need to stand the test of time, but what's for sure is that some of them will help reshape the future of web development.

P.S., We're building ZenStack, a toolkit that supercharges Prisma ORM with a powerful access control layer and unleashes its full potential for full-stack development.

Top comments (4)

t0nyba11 profile image
Tony B

This is quite wrong... "As long as you have any public API that allows CRUD operations, you're already "exposing".

The difference is the layer of Authentication and Authorization and "Firewalling" that happens at the API level, that cannot really be done at the Database level, as Databases are not designed for it. Yes, there are things you can do to improve security, but at the end of the day, just don't do them - keep your databases on private networks always.

ymc9 profile image

I agree with you that directly exposing traditional SQL databases is not a great idea. Even RLS feels like an afterthought. But we can always think freely about the future of "relational data stores":

  • It doesn't need the full power of SQL (at least for OLTP)
  • It can have authentication/authorization as a more integral part

Are they still databases? I think they're, but they can be designed to be exposed by default, just like most other services are.

franckpachot profile image
Franck Pachot

Great article. There's a difference between opening the DB to public network and having all CRUD to all tables opened. Many databases provide declarative access control which may be more robust than application code. Row level security, or stored procedures to encapsulate the SQL access.

ymc9 profile image

Absolutely! RLS and stored procedures are great weapons that help you "exposed" in a controlled way.