What Is Code Security?

Understanding code security

Code security is the practice of ensuring code is as secure as possible. It applies to application source code (meaning the code that determines how software operates) as well as to configuration code (meaning any code-based resources that define environment settings or other configuration variables).

Most organizations want code to be secure, of course, and in a sense, code security is always an inherent goal. But by making code security an explicit priority, businesses send a message that they want to take a proactive approach to ensuring that code is free of risks and vulnerabilities for the very start of the software development lifecycle (SDLC).

Key types of code vulnerabilities

To understand why code security is important, let’s discuss common vulnerabilities that can appear in code and how code security helps mitigate them. This list of vulnerabilities is not exhaustive – there are many other types of potential risks that are not discussed below – but it covers many typical examples of issues that can arise from insecure code.

Injection vulnerabilities

When an application accepts input from users, malicious users can potentially insert data that is designed to cause the application to behave in a way developers did not intend. This leads to what’s known as an injection vulnerability. These typically occur because applications do not properly validate user input to block malicious data.

For example, imagine that an application passes an input string directly to a database without validating it. In this case, a threat actor could insert a SQL query that tells the database to display sensitive data. Code security can help to prevent injection vulnerabilities by encouraging developers to ensure that any code they write to accept user input into an application is accompanied by code that validates the input and blocks malicious queries.

Buffer overflow

Buffer overflow attacks allow threat actors to execute arbitrary code, meaning that they can inject their own malicious code into an application and cause the application to run it. Typically, they do this by taking advantage of flaws within applications that make it possible to overwrite portions of a system’s memory.

To prevent this type of attack, developers must ensure that the code they write manages memory properly. It’s also important to check the length of input strings, since long strings could be used to overwrite memory.

Privilege escalation attacks

In a privilege escalation attack, a user gains access rights or permissions that should not be available based on the user’s original role. There are many potential causes of privilege escalation vulnerabilities, and not all of them involve insecure code, but many do.

For example, poorly coded authentication or authorization functions could allow attackers to bypass the access controls that are supposed to be present within an application. In other cases, mistakes in configuration code may allow a user to access features or capabilities that should not be available, but that are accidentally exposed due to configuration variable settings.

Here again, writing secure code – whether it’s application source code or configuration code – is important for preventing this type of risk.

Insecure dependencies

It’s common for applications to include code that references libraries, modules, or other external resources. In cases where this code contains typos or fails to specify an exact version of the resource, attackers could potentially insert malicious resources in place of the ones that developers intended to use. The result is that the application imports and runs an insecure dependency through what’s known as a dependency confusion attack.

Code security helps to mitigate this risk by encouraging best practices that mitigate attackers’ ability to inject insecure dependencies into an application or its host environment. For example, a code security best practice is to specify the full path to a container registry and image version when importing a container image from an external source. Doing so reduces the risk that an application will default to using a registry or image version that attackers control, rather than a legitimate one.

Obstacles to implementing effective code security

Recognizing the benefits of code security – above all, the decrease in cybersecurity risk that it enables – is one thing. Actually implementing code security, however, can be another, due to a variety of common obstacles:

• Code scale and complexity: Perhaps the greatest obstacle to code security is the sheer scale and complexity of modern codebases. It’s not uncommon for an application to include tens of thousands, if not hundreds of thousands, of lines of code. Since vulnerabilities can lurk within any of those lines of code – and because code is often interdependent, with one part of an application impacting the way other parts operate – it’s hard to guarantee that all of the code within a sprawling codebase is secure.
• Lack of security expertise among developers: Many software engineers lack extensive training or experience in cybersecurity best practices. They may be familiar with the fundamentals of code security, but they aren’t always aware of the latest attack techniques. To code securely, they benefit from guidance from security engineers, who can collaborate with developers using a DevSecOps approach.
• Multiple languages: Although code security best practices – like validating input and managing memory securely – are the same across all programming languages, implementing these practices can vary from one language to the next, making it challenging for developers to take a consistent approach to code security.
• Time pressures: Often, developers face pressure to release applications or application updates within a specified time period. They may worry that excessive emphasis on code security will slow down development operations, leading to delayed releases.
• Insecure dependencies: Importing libraries, modules, or other third-party dependencies into applications or environments can save time because it avoids the need for developers to implement all functionality from scratch. However, developers don’t have control over the security standards of third-party projects, so depending on external code could introduce risks into applications.

Integrating code security into the development lifecycle

The best way to balance the need for code security with pressure to release applications and updates early and often is to integrate code security into the software development lifecycle. This means making secure coding a priority from the start of the development process, as well as continuing practices that help to identify and fix insecure code during later stages of the SDLC.

The precise way in which an organization integrates code security into its SDLC depends on factors like which type of application it’s developing and which tools it uses. But in general, the process looks like this:

• During the planning stage of the SDLC, developers assess which application features and capabilities (like strong authentication) they should implement to make applications as secure as possible. By including a focus on security at the very start of the SDLC, organizations can shift security left. 
• During the design phase, they take steps to implement a design that will optimize code security. For instance, they may break a complex codebase into smaller parts, which can help to enhance security because it’s easier to avoid security issues when you’re working with smaller, less complex units of code.
• During the coding phase, developers adhere to best practices in writing code, such as ensuring that applications include logic to validate input. Keeping code clean and concise can also improve security because it makes it easier to understand what code does, which by extension means that developers can more readily identify flaws that may lead to security issues.
• During the testing phase, engineers employ multiple types of security scans to identify insecure code that, despite developers’ best efforts, may have appeared within the codebase.
• After deployment, security testing and monitoring continue as part of a shift-right security strategy, which helps mitigate security risks that may still exist in the code.

In addition to securing code at these various phases of the SDLC, integrating code security into the development lifecycle also includes managing code in a secure fashion and mitigating CI/CD security threats. For example, code repositories should be locked down with access controls to prevent unauthorized parties from injecting malicious code into them. Secrets should also be managed securely so that passwords, access keys, and other sensitive data don’t fall into the hands of threat actors.

Tools and techniques for strengthening code security

While code security requires more than simply deploying certain types of tools or running certain tests, there are various code scanners and scanning techniques that can enhance the security of code across various stages of the SDLC.

Code linters

Linting tools help to improve the quality of code by making it cleaner and more readable. Their primary purpose is not security, but they can enhance security because, as noted above, the more readable code is, the easier it is to identify flaws that could lead to security vulnerabilities.

SAST scanners

Static Application Security Testing (SAST) scanning tools analyze source code and/or binaries to detect flaws like buffer overflow vulnerabilities or lack of proper input validation. They won’t necessarily catch all flaws, but they can detect some issues that developers accidentally overlooked, enabling secure code review.

DAST testing

Dynamic Application Security Testing (DAST) is a technique where engineers automatically simulate malicious interactions with running applications and evaluate how they respond. DAST is useful for detecting issues like code injection risks that SAST scanners might have overlooked.

SCA scanners

Software Composition Analysis (SCA) tools evaluate application third-party resources within applications and flag those that may be insecure. These help to prevent software supply chain attacks.

Secrets scanners

Secrets scanners can identify hard-coded secrets, allowing developers to remove them from codebases and reduce the risk that threat actors will discover them.

IaC scanners

Infrastructure-as-Code (IaC) scanners check IaC files for oversights or mistakes that could lead to IaC security issues, such as the granting of access privileges to unauthenticated users. This is an example of a code security tool that helps protect configuration code, as opposed to application code.

Essential best practices for securing your code

In addition to deploying the right tools, organizations should embrace best practices like the following to help optimize code security.

Validate input

As noted above, lack of input validation is one of the most common sources of security issues within code. It’s a best practice to ensure that whenever developers implement logic that allows an application to accept input, they also write code to validate the input.

Avoid hard-coding secrets

Instead of hard-coding passwords, access keys, and other sensitive data directly into code, engineers should use a secrets manager. Secrets managers allow for the secure storage of secrets and make it possible for applications to access them on-demand, with authentication required.

Handle errors securely

When applications generate error messages or codes, they may include data that threat actors could use to understand how an application works and direct attacks at it. As a best practice, errors should be handled securely, in such a way that only authorized users can view error messages or logs. In general, error data should be not viewable by ordinary end-users.

Avoid unnecessary code

The shorter and simpler a codebase is, the easier it is to maintain high code security standards. To this end, developers should aim to make code as concise as possible, so long as it doesn’t become so concise that it’s difficult for other developers to read or understand. They should also remove obsolete code from codebases in instances where they abandon or replace a feature and no longer need the code originally associated with it.

Implement strong authentication and authorization

Rather than exposing all application functionality to all users, it’s a best practice to define different types of users and roles, and then implement authentication and authorization controls that determine which users can access which features based on the roles associated with the users.

Aqua Security’s approach to Code protection

Prioritizing code security from the start of the SDLC and detecting code security risks that may arise at the various stages of the SDLC is hard work. It requires a variety of tools and practices, as well as effective collaboration between developers and security experts.

As an application security platform that delivers end-to-end protection against a wide variety of risks, Aqua helps enable code security across the SDLC. Aqua supports a variety of scanning and testing techniques to help identify coding flaws. It also offers remediation guidance, which helps developers fix code security issues without slowing down software development operations.

To learn more about how Aqua can optimize your organization’s approach to code security, request a demo.