Zero Trust Approach to Cloud Data Security through Software-Defined Perimeter (SDP)
Tags: security, cloud, sdp, database
Published: 2023-04-19 15:00:52



Servers, routers, and other internet-connected hardware can be concealed using a software-defined perimeter (SDP) so that outside parties and intruders cannot see it, whether it is located on-premises or in the cloud. The SDP method aims to replace the hardware-based network boundary with software. When a business employs an SDP, it's like casting a veil of invisibility over its servers and other infrastructure, making it invisible to outsiders but accessible to authorized users.

An artificial barrier is created around corporate assets via an SDP at the network layer rather than the application layer. This sets it apart from other access-based security measures that limit user rights while allowing unlimited network access. An SDP authenticates devices in addition to user identities, which is another significant distinction. The idea of the SDP was initially thought of by the Cloud Security Alliance.

**How Does SDP Work?**

Software-Defined Perimeter (SDP) enhances [cloud data security](https://www.sentra.io/cloud-data-security) by granting access to servers only after user and device authentication. Technically, SDP operates on a zero-trust model, with the implementation often utilizing mutual Transport Layer Security (mTLS) for secure communication.

Upon user and device authentication, the SDP controller establishes a secure connection between the device and server using mTLS. For instance:

```python

const tls = require('tls');
const fs = require('fs');

const options = {
  key: fs.readFileSync('server-key.pem'),
  cert: fs.readFileSync('server-cert.pem'),
  ca: [fs.readFileSync('client-cert.pem')],
  requestCert: true,
  rejectUnauthorized: true
};

const server = tls.createServer(options, (socket) => {
  console.log('server connected',
              socket.authorized ? 'authorized' : 'unauthorized');
  socket.write('welcome!\n');
  socket.setEncoding('utf8');
  socket.pipe(socket);
});
server.listen(8000, () => {
  console.log('server bound');
});

```

Each authorized user receives a unique, secure connection, granting access only to permitted services. This approach provides stronger cloud data security compared to conventional, open networks.

In an SDP, servers are isolated by default, with no open ports or exposed services. The architecture is similar to a locked entrance, where authentication is required before granting any access. Once authenticated, the connection is secured, maintaining the zero-trust model.

By implementing an SDP with mTLS and strict access controls, developers can substantially bolster their network and cloud data security.

**What Does an SDP Intend to Achieve?**

[SDPs](https://www.cloudflare.com/learning/access-management/software-defined-perimeter/) provide secure access to network-based services, apps, and systems in public and private networks as well as on-site. It is vital for cloud data security as well. Since it obscures systems by cloaking them within the perimeter so others can't view them, the SDP technique is frequently described as producing a black cloud.

SDP software, created especially for medium and large companies, offers the peripheral security infrastructure necessary for zero-trust apps and [workload-centric](https://www.zscaler.com/resources/security-terms-glossary/what-is-cloud-workload-security) network access. It can be installed on any host without needing network reconfiguration or device lock-in. Therefore, an SDP's virtual border around the network layer lowers the attack surface and eliminates vendor chaos.

**Architecture of SDP**


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/w57iw0jyu9emt3rstyne.png)


[Source](http://networkworld.com/article/3359363/software-defined-perimeter-brings-trusted-access-to-multi-cloud-applications-network-resources.html)

By authenticating people and devices before allowing the user-device combination to safely connect to the isolated services, an SDP framework provides an on-demand, dynamically provisioned, air-gapped network—a segmentation of network resources that simulates a physically defined network perimeter but runs in software rather than via an appliance. As a result, the protected resources are inaccessible to unauthorized users and devices.

Trusted devices are provided a specific and temporary connection to the network infrastructure when authentication is complete. Businesses can streamline operations in terms of user authentication and application security with the SDP framework.

SDP controllers and SDP hosts are the two primary parts of SDP architectures. Which SDP hosts are capable of communicating with one another is decided by an SDP controller. An SDP host may be accepting or initiating. 

A starting SDP host talks to an SDP controller to find out which hosts they may connect to. An accepting SDP host will only accept connections and communications that have been authorized by an SDP controller. In some SDP topologies, a gateway might act as the accepting host between two connected users or devices.

**What is the Relationship between SDPs and Zero Trust Security?**

There is no trust within [zero trust](https://www.microsoft.com/en-us/security/business/zero-trust) security, as the name indicates; no user, device, or network is deemed trustworthy by default. No matter if they are inside or outside the network boundary, every person or device trying to access internal resources must undergo stringent identity verification under the principles of zero trust security (or the SDP).

SDPs are one method of implementing zero trust security. Users and devices must both be validated before they may connect, and they only have the bare minimum of network access. No device may establish a network connection to a resource that it is not permitted to utilize.

**Summary**

Organizations may fight against new varieties of well-known attack techniques that are continually emerging in current network and infrastructure perimeter-centric networking paradigms by implementing zero trust utilizing SDP. Businesses facing the difficulty of constantly adjusting to expanding attack surfaces that are ever more complex might enhance their security posture by implementing SDP. 

This article explained what SDP is and why SDP is applied to network connectivity, which focuses on securing all connections utilizing the underlying IP-based infrastructure and is the optimal architecture for attaining zero trust.