6 Essentials for Foolproof Source Code Security

In today’s digital economy, businesses depend on developers and engineers to write code that powers their most important customer-facing services. Research from 2021 found that 82% of Americans pay for goods and services using digital payment methods. These payments are made possible by the background source code that drives the functionality behind browser-based and in-app online purchases and transactions.

With source code being front and center of many digital business operations, source code security weaknesses can wreak havoc. The potential consequences of security incidents exploiting weak source code include costly downtime, stolen information, lost business partnerships, damaged reputation, and fraudulent transactions.

To prevent these outcomes, it’s imperative to pay as much attention to security as to features when writing and maintaining code— foolproof source code security is the goal, and here are six essential steps that can help you achieve it. 

What is source code and why is it valuable?

Source code is a collection of instructions or statements written in plain text in the lexicon of a particular programming language. Together, these instructions and statements are the fundamental building blocks of computer applications. For example, the HTML on a given website tells the user’s browser how to display the site’s texts, links, fonts, media, and more.

For any company providing digital products or services, source code is one of its most valuable assets. Whether it’s a mobile banking app, a popular eCommerce store, or a large social networking app, writing and maintaining effective code is critical in a digitally-transformed landscape. 

Of particular value is any proprietary code developed in-house because this code is unique to a specific organization. Most modern applications combine widely available open source code that provides ready-made functionality and in-house source code that gives apps a competitive edge through proprietary features or designs.  

Source code is so valuable that many organizations identify and seek to protect their proprietary code as a trade secret. Any software-led business should effectively guard its source code as a significant type of intellectual property (IP) like any other type of sensitive data. But with code, there are additional security concerns to think about. 

Why your source code needs foolproof security?

A diverse range of security concerns make protecting source code more complicated than other digital business assets. For starters, experienced hackers regularly seek out code security flaws to achieve their nefarious goals. A 2021 report found that 50% of all web applications were vulnerable to attacks that exploit code weaknesses such as cross-site scripting and session hijacking. 

Accidental source code leaks are another security concern. A problem known as secret sprawl means that source code often contains secrets, including encryption keys, tokens, SSH keys, and passwords, without organizations knowing about it. Source code security must be foolproof to limit the chances of accidental leaks and code weaknesses. 

Lastly, there are compliance concerns to consider. When threat actors exploit source code weaknesses or human error, there could be incidents in which payment card information (PCI) or personally identifiable information (PII) are accessed in breach of standards and regulations. These breaches come with penalties, litigation fees, and reputation damage. 

6 essentials for foolproof source code security

1. Beware of the hidden risks of third-party apps

The complexity of modern digital ecosystems is such that websites, web apps, and other online properties often depend on both source code and third-party apps. For example, an eCommerce site might use custom-coded pages along with third-party marketing analytics and payment processing apps. 

A prime example of hidden risks occurred in the Magecart wave of attacks in 2022 that targeted 311 restaurants by injecting malicious JavaScript code onto a third party online ordering platform. Many victims of these Magecart incidents had their own custom-coded websites but relied on the same ordering platform for important functionality. Payment card information from thousands of customers ended up on the dark web as a result.

So, the first part of effective source code security requires a granular understanding of your site or app’s third-party risks. You need visibility into all third-party activity to see which digital assets are running, their behavior, and their security implications. Solutions that help build an inventory of this information without any performance hit or requirement to access sensitive data can save a lot of time.

2. Leverage Software Security Assurance (SSA) for apps coded in-house and outsourced

The concept of software security assurance (SSA) is a useful one to adopt when you need foolproof security. By taking a secure-by-design approach to code, SSA aims to eliminate software’s most prominent source of security vulnerabilities: defects. These defects could make it into code either because the code doesn’t conform to requirements or because the requirements themselves are incomplete. 

For eCommerce companies and other Internet-driven businesses that depend on integrating multiple software components, SSA is worth using as a security benchmark both in-house and for any outsourced applications. When all your code has to meet an SSA ethos, you can be confident that apps conform to their security requirements and don’t include any functionality that could compromise security.   

3. Manage your secrets as if they were… secret!

Speaking of accidental source code leaks, foolproof security requires you to minimize or eliminate the likelihood of developers embedding secrets in code. One approach that can pay dividends here is to emphasize secrets management. 

By actually managing passwords, keys, APIs, and tokens as the secrets that they are, you can securely store, transmit, and manage sensitive digital authentication credentials. Automated tools can assist with this, but secrets management should be part of your overall security policy, with a particular emphasis placed on instructing developers never to hardcode or upload secrets to code repositories. 

4. Gain visibility beyond your server

A bias toward securing the server side of client-server communications leads many organizations to overlook weaknesses originating outside their perimeter. These vulnerabilities only emerge during the interaction between a client browser and a web app or website. Potential risks include broken access control, outdated client-side components, and XSS. 

Security tools usually have visibility and control of the server side of things, where it’s more straightforward to flag code weaknesses. Visibility beyond the server is essential for businesses to see what’s happening, flag client-side risks, and mitigate vulnerabilities before a threat actor exploits any weaknesses. 

5. Consider your criteria for selecting a SAST tool

Central to avoid many source code security issues is testing your code thoroughly. Static application security testing (SAST) tools efficiently scan code and help detect a slew of common vulnerabilities. The beauty of these tools is how well they scale and how you can run them repeatedly. Still, you should also carefully select your SAST tool based on essential criteria including:

• Accuracy
• Whether the tool detects all the OWASP Top Ten
• Support for your programming language
• Ease of use

You may have other factors to account for, but these criteria are the minimum to think about when selecting any SAST tool. 

6. Protect source code access and storage

A harsh truth about source code security is that your code is only as secure as the systems used to store and manage it. Even if you heed the previous advice, a mistake or weakness here can render all other source code security efforts futile. 

Most organizations today use some sort of code repository where developers can benefit from version control, peer review, and remote collaboration, among many other advantages. Since these repositories can’t be accessible to anyone, their security (and the security of your code) depends on enforcing effective access control and understanding what’s happening in the repository. 

Identity and access management tools can help to control access, but the security principles upon which you control access using these tools are equally important. Make sure to use the least privilege principle, which ensures only the users who strictly need source code access get that access with the minimum necessary permissions. Also, revoke access for freelancers, employees, and other contractors when no longer required, either because they’ve left the company or are no longer contributing to a project.   

Conduct periodic reviews of code repository access to flag dormant accounts with access. Lastly, regularly audit changelogs in your code repository to flag potentially suspicious source code modifications that could allow malicious outsiders a backdoor into your environment. 

Everybody wins from secure applications 

Every party involved in the complex ecosystem that defines modern web applications benefits from strong source code security. While the steps outlined here will help you improve your organization’s code, verifying that you’re using secure code is as important as securing the code/software you make available for others.  

With companies becoming more reliant on integrating third-party apps and code with their apps and websites, a software bill of materials (SBOM) is increasingly important for full transparency and understanding of code risks. This bill of materials lists all the components and elements that form a software product so that you can know what you’re getting and mitigate potential software supply chain risks before it’s too late. Read more here on software bills of materials and how it helps to secure your applications from supply chain threats.