As software developers working on proprietary software, it's our job to create programs that provide the functionality our clients need. And it's also our job to create those programs in a way that makes them easy to use, maintain, and upgrade.

But proprietary software developers have another, much more consequential responsibility, too. We've got to create software that's secure and doesn't put user data or our clients' systems at risk.

And the key to doing that is to harden our source code and tighten up our development processes to prevent malicious actors from injecting anything harmful as we work.

Those types of efforts are crucial because source code is the base component of a computer program, so we need to protect it from any unauthorized alterations.

This article will explain why securing source code is so important for proprietary software projects. It will also give programmers some tips on securing their source code, as well as some guidance on protecting it from outside alteration during the development process.

Why is it Important to Secure Your Source Code?

The use of open-source code in the development of proprietary software is booming. At last count, it's estimated that up to 96% of proprietary software contains some open source code. Developers use those code bits to speed up the development process and avoid unnecessary work. And from a security standpoint, that's a good thing.

According to most security experts, open-source code is more likely to be secure and stay secure due to the sheer number of eyes that review it over time.

But once a developer starts cobbling together open source code and adding their own customizations to create something proprietary, all bets are off. From that point on, it's on them to avoid adding any vulnerabilities that could lead to a data breach or hack.

And depending on the nature of the software in question, there's a variety of data that could be at risk within your finished software, including:

  • Passwords
  • Encryption keys
  • IP addresses
  • Authentication tokens, and much more.

That makes the threat of a source code leak a major one for any developer of proprietary software. And that threat isn't just theoretical. There've been multiple instances of proprietary code leaks in recent years. And in many of those cases, the ultimate consequences are still far from clear.

But in one case — the leak of Twitch's entire source code repository — the consequences were severe. According to a review of the data, hackers gained access to almost 7,000 secrets. Those secrets, consisting of the types of data listed above, could give attackers catastrophic access to the platform.

The Main Threats to Source Code Security

There are two main categories of threats to source code security:

Insider Threats

Source code is at the mercy of developers and anyone else that has access to it. That means limiting access to your source code and establishing security guidelines for those with access is vital for increasing security.

It's also important to realize that insider threat actors aren't always malicious. Often, insider threats come from mistakes or negligent actions taken by employees.

For example, a programmer might share parts of the source code on an online forum to get feedback or solve a problem — leading to that code ending up in the wrong hands.

Outside Threats

Outside threats come from outside of your development team. They may come from competitors that want to use the code to improve their own. Or, they can come from hackers who will attempt to sell your source code or pick it apart looking for vulnerabilities.

The point is, whether a leak comes from inside or outside threats, it can have terrible consequences. Source code leaks can lead to additional attacks, exposing large amounts of sensitive data.

Source code leaks can also lead to financial losses by giving competitors an advantage. And your customers will think twice before dealing with a developer that has exposed valuable customer data in the past.

Regulations around security are also becoming stricter. Your clients can face hefty fines if they fail to protect their data — and they'll hold you responsible for that.

How to Secure Your Source Code

Now that you know the importance of securing source code, let's look at some ways you can bolster your source code security:

Implement Secure Development Practices

Your source code's security starts at the beginning of the development cycle. The sooner you detect security flaws within the code, the better.

You must define a clear set of coding practices, rules, and procedures right at the start of each process. That includes training your development team on the best security practices and providing them with documentation of security standards they need to meet during the project.

The Open Web Application Security Project (OWASP) offers a comprehensive framework that makes a great starting point. Although it's tailored for web applications, its concepts are broadly applicable to all kinds of software development work.

Its most important points include:

  • Conducting all data validation and encoding on a single trusted system
  • Requiring standardized, tested authentication for access to project resources
  • Take steps to reduce code complexity wherever possible for easier security auditing
  • Protect and encrypt project-related code repositories
  • Secure and protect your build development pipeline

By keeping your code and development process in line with established security best practices like the ones above, you can drastically reduce the odds of your code getting compromised either during development or after it's published. As they say, an ounce of prevention is worth a pound of cure.

And once the code is written, you should also use security analysis tools to identify security flaws and other risks. Code analyzers will also scan to ensure compliance with best security practices and coding standards. The tools will help you to identify risks and correct the underlying issues before it's too late.

Some of the most commonly-used tools for this include:

  • Appsonar – automates best practice testing across more than 15 languages and scans for known code vulnerabilities
  • Codiga – checks for best practices, security, safety, and design issues across 18 languages and frameworks
  • Mend SAST – provides automated vulnerability scanning and automatic remediation of known vulnerabilities

Encrypt and Monitor Data-in-Transit

Data encryption is crucial in securing your source code. And data in transit is particularly vulnerable. So it's a good idea to find ways to keep your code secure as it passes between members of the development team.

A good place to start is by using a code sharing or collaboration platform that includes end-to-end encryption.

There are a variety of solutions aimed at software developers that include encryption. Some of the most-used options include CryptPad, CodeTogether, and Visual Studio Live Share. Depending on the nature of your particular project, one of them is sure to make a valuable addition to your team's toolkit.

If a code-sharing platform is overkill for what you're working on, you can use an encrypted filesharing platform instead and use it to exchange code snippets. And if you're working with a team that's not all within a single office, it's a good idea to invest in a VPN. The VPN will mask your IP address and encrypt all data transfers between your networks.

But be aware that VPNs often slow down your internet speeds, so you should do your research before purchasing one for you and your team. Some VPNs are much faster than others and only slow down your speed incrementally, so choose wisely or you could harm your team's productivity.

Control Access

The only people who should have access to source code repositories are developers and quality control staff. There's no reason to give access to anyone who's not hands-on with coding.

By limiting the number of people with access, you can significantly decrease the risk of insider threats. Protect your code with authentication and authorization access control.

Conduct Secure Code Reviews

Secure code reviews are a critical part of the SDLC (Software Development Lifecycle). Reviews are particularly important for security. They allow team members to identify and resolve any potential security vulnerabilities before the code goes live. In many industries you might work with, reviews are mandatory for regulatory compliance.

But it's important to differentiate between code review and secure code review. The latter should focus strictly on "hardening" the code security-wise. Regular reviews mainly focus on fixing potential bugs or glitches. Those happen more frequently while your codebase is under heavy development. Secure code reviews should happen primarily when your code's close to a release.

At that stage, it's a good idea to apply some comprehensive hardening techniques to make it more difficult for hackers to gain access to the software through analysis or at runtime.

Some hardening techniques include:

Depending on the sensitivity of the data your software is dealing with, you may need to go much further than the techniques I've shared above. You should always heed the security needs of the client above all else — even if they ask you to harden your code beyond what you believe is necessary.

Final Thoughts

Proprietary software developers need to pay careful attention to source code security. Those that don't risk exposing themselves and their clients to massive risks that are largely preventable.

So, throughout the development process, you need to guard against inside and outside threats. Failing to do so can put sensitive data at risk, potentially leading to significant financial and reputational damage — for everyone involved.

Image licensed Gorodenkoff via Adobe Stock Photos