Certificate Pinning — Does It Help App Security?

Cybersecurity for apps is a critical aspect of securing business activities. As applications are connected to the cloud and used over various networks, they are more prone to security vulnerabilities such as man-in-the-middle (MITM) attacks. 

An Accenture report states that cyber attacks saw an increase in 2021, rising to 270 from 206 per company. While SSL/TLS certificates ensure user data remains uncompromised, hackers can intercept the communication between the app and server to represent a fake certificate.

Therefore, it has become necessary for DevSecOps teams to mitigate the risk by providing an extra layer of security, like certificate pinning for the apps. This will ensure hackers cannot intercept the SSL certificates to gain access to financial information, login credentials, etc. 

But what is certificate pinning, how it works, what are its caveats, and how can it be used in conjunction with code security? Find out below.

What Is Certificate Pinning?

Certificate pinning is an additional layer of security for an app’s SSL/TLS certificate. It involves pinning the SSL certificate to a root certificate instead of a standard trust store on a device. 

A root certificate can be a specific public key or a guarantee signed and issued by a trustworthy Certificate Authority (CA) that establishes trust in an SSL certificate. This ensures the app will only accept the certificate it is programmed to trust specifically. Thus making it harder for an attacker to create a fake SSL/TLS certificate. 

How Certificate Pinning Works

The root certificate comprises information such as name, location, digital signature, and public key from the trusted CA. When a browser establishes a connection with a website, it checks the SSL certificate information against the pinned root Certificate. 

If the details match, a secure and encrypted communication channel is established between the browser and the server. However, if the information doesn’t compare, the browser won’t connect and will warn the user of a potential attack.

This ensures that even if an attacker intercepts the communication, they won’t be able to issue a fake SSL certificate, as the browser will reject it. 

In Which Situations Certificate Pinning Is Advantageous?

SSL certificate pinning is helpful in many situations where app security can be compromised. 

To Prevent MITM Attacks

As pinning ensures the apps accept only a specific certificate, it protects against MITM attacks. The hacker cannot break into HTTPS traffic between a browser and a server, even if they manage to intercept the communication.

To Transfer Confidential Data

All apps, especially E-commerce, financial, and third-party APIs, transfer sensitive information which can be compromised in the event of a cyber attack. But pinning ensures the data is transmitted over a secure channel. 

To Secure Internal Networks

In organizations where there is an acute need for trusted internal networks, pinning adds an extra layer of security to SSL certificates. This ensures that only authorized internal certificates can secure the communication.

To Establish Trust for Non-Trusted Networks

Public hotspots are non-trusted networks where pinning ensures the client (browser) intercepts the expected certificates, even if a network is compromised.

What Are the Limitations to Certificate Pinning, and How to Reduce Them?

When implementing certificate pinning for apps, there are certain caveats to consider and steps that can minimize potential drawbacks:

Update the Root Certificate

Root certificates require regular updation. Otherwise, they lead to lost traffic, broken links, or error messages. To ensure their validity, they must be kept up-to-date. There should also be a mechanism in place to update the certificate quickly in the event of a security breach or if they are revoked. 

Reduce Limitations

Pinning limits the flexibility of an SSL/TLS certificate, as only a specific CA can issue it. To minimize this drawback, certificate pinning must allow switching to a different root certificate if required. 

Minimize False Positives

Sometimes pinning can result in a false positive where the browser rejects a legitimate SSL certificate to warn the user of a potential attack. To reduce false positives, certificate pinning must be tested and validated before implementation. Moreover, detailed error messages must be provided to users whenever false positives occur.

Implement Multiple Root Certificates

Not all browsers support certificate pinning. To reduce this limitation, a specific system must be in place to allow support for multiple root certificates. In addition, the mechanism must also enable non-supportive browsers to access websites. 

How Can DevSecOps Implement Certificate Pinning With Code Security?

Certificate pinning is a critical security technique for DevSecOps teams to improve the security of their apps and provide quicker incident responses. It can be used in conjunction with a pre-emptive code security tool like DashO to prevent security vulnerabilities.

This enables the developers to provide multiple forms of obfuscation, making it impossible for attackers to hack through layered security. Here’s how pinning can prevent security vulnerabilities in code security during the app development phase:

Minimize Attack Surface

By restricting the trust of SSL certificates to a set of trusted root certificates, developers can reduce the attack surface of applications, preventing MITM attacks. Besides, pinning with code security also enables apps to detect if someone tampers with the certificates and terminates the connection if they are invalid.

Improved Incident Response

Integrated with a code analysis tool like JS Defender, pinning allows for quicker incident response. In the event of a security breach, it enables the DevSecOps teams to find the source of a problem in the code and fix it in record time.

Integration With CI/CD Pipelines

Certificate pinning can be integrated into CI/CD deployment pipelines. Implementing it in the app development process, especially during the testing phase, allows for quick validation of the code and the authenticity of the certificates. 

This ensures that the code is more secure and less vulnerable to security risks such as weak certificate validation and hard-coded certificates.

The Bottom Line

The ever-increasing popularity of mobile apps makes them a prime target for malicious attacks. According to a recent study, most Android apps are prone to cyber hacking, with 16% having no solution for this problem. 

Hackers can easily exploit code security to steal financial information and login credentials. But certificate pinning is a critical aspect of DevSecOps, adding an extra layer of encryption to app security during the development process. It ensures the apps not only rely on the trust store of their device but also require additional verification. 

Integrated with the PreEmptive Mobile App Protection Solution, pinning provides foolproof code security, making the apps more resilient to unauthorized debugging, and reverse engineering. Register today for absolute app protection!