Security Code Reviews: Protect Your Business

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Data breach and cyber-attacks are moving on to become extremely scary and costly to deal with. That’s when it becomes extremely important to protect your code.

Protection of code is an integral part of contemporary software application systems.

It has become an essential component of all software development and maintenance strategies to ensure integrity and accessibility of applications.

In this blog, we will explore the process of secure code reviews and why they are so important for your business.

What is a Security Code Review?

A security code review is a process of inspecting application source code to identify potential security issues and inefficiencies.

A code review typically involves analysis of high-level design and security-sensitive areas of the code that are not covered by automated tools.

Since such a review is performed on the actual source code, it provides deep insight into implementation-specific details and checks whether certain assumptions hold true across different parts of the code.

Examples of these checks include reviewing who may call a certain function, what input is accepted, and how failures are handled, among others.

Code reviews may also be referred to as security code audits or security code analysis. For the purposes of this article, we will use these terms interchangeably.

Security code reviews are performed by engineers with extensive knowledge and experience in cybersecurity-related fields.

They analyze all the elements that may introduce an impact on the possibility of an attack or system stability:

Authentication and authorization logic
Data flows
Trust boundaries, and others

Many companies opt to contract this service to an outside vendor to benefit from an objective assessment and to have access to engineers with specialized expertise that would be difficult to hire internally.

How will a security code review help your business?

Identifying vulnerabilities beforehand allows organizations to deal with them at a stage when solutions can be predicted in terms of their predictability, predictability, and cost.

From a business perspective, the main advantages of security code review are:

Advantage: Lower risk of security breaches

How Security Code Review Helps: Security code review identifies vulnerabilities before release, which reduces the chances of security incidents.

Advantage: Lower remediation costs

How Security Code Review Helps: Remediation of vulnerabilities is much cheaper when done in the development phase than in response to incidents.

Advantage: Increased transparency in decision-making

How Security Code Review Helps: The findings are linked to specific code components and thus allow prioritization of fixes and planning of releases.

Advantage: Assistance in compliance and auditing

How Security Code Review Helps: A report provides documented evidence that security risks have been systematically analyzed.

Advantage: Defense of reputation and customer trust

How Security Code Review Helps: Extra effort to review project security helps avoid negative consequences for the reputation.

When to Perform a Security Code Review

Organizations typically do not perform security code audits at every stage of the product development lifecycle.

There are particular situations, events, or circumstances when a business may find it beneficial or necessary to perform an independent security code audit.

An external security code analysis is usually requested by organizations in the following cases:

1. When designing and implementing security products and solutions that process sensitive data.

In other words, a security code audit is useful for products and solutions that, by their nature, bear responsibility for ensuring the required level of information security.

This applies to security products (EDR, XDR, SIEM), their components (drivers), or applications that process personal or confidential data or provide encrypted data transmission.

In such cases, it becomes especially important to evaluate the security of critical components and eliminate potential vulnerabilities in critical infrastructure.

2. When restructuring or purchasing products or companies.

In other words, when acquiring software products, a security code audit is performed to assess the level of information security and the corresponding risks.

Audits of this type are also relevant in situations of technical staff changes and large-scale project redesigns.

It is important to note that in such cases, an external, independent security code review is helpful in finding vulnerabilities and understanding the necessary steps for further work.

3. When preparing for compliance audits and certifications and need to analyze the code for vulnerabilities with independent experts.

It is always preferable to find and fix known security issues before external organizations check the code.

In addition, a security code audit helps in preparing project documentation and justifying the choice of a particular product for integration.

4. When there is a need to harmonize code with applicable security policy and regulatory requirements.

In other words, when an organization has a documented set of requirements for code quality control but lacks the expertise to implement it.

In such cases, an independent security code audit is helpful since independent auditors have well-defined processes and approaches for working with particular code bases.

Moreover, they have proven practices for translating theoretical knowledge of policy requirements (OWASP, CIS, etc.) into specific practical tasks.

5. When designing products (applications) to find potential vulnerabilities before attackers can use them to gain unauthorized access to data or the system.

Experience shows that the later a vulnerability is found in the development lifecycle, the more costs and time are needed to fix it.

Exploiting known weaknesses can lead to information leakage, security breaches, and damage to the organization’s reputation.

This is especially true for vulnerabilities that go unnoticed and are not on the radar of product owners and developers.

On the day of the product launch, such flaws become critical and require immediate fixes, which often involves spending a lot of time and effort on the emergency repair.

6. When optimizing code for performance and scalability issues.

A code audit helps find design-level vulnerabilities that affect system performance or scalability.

For example, the use of error handling mechanisms that are too weak or, conversely, overly redundant code, or incorrect synchronization of processes with a particular resource can cause problems with code execution.

The auditor also examines the entry points in the code and interaction points with other applications to better understand how attacks can affect the system.

This, among other things, helps to identify assumptions that may be incorrect, trust boundaries that are not properly defined, and potential weak points in the code.

7. When analyzing whether the legacy code needs to be re-written or reworked.

Legacy code often contains various assumptions and solutions that are no longer applicable and are inconsistent with the requirements of modern information security.

This also means that such code is much more vulnerable and challenging to maintain and scale.

A security code audit helps to identify exactly what weaknesses legacy code has and how these weaknesses can be resolved to bring the code into line with current requirements.

Security Code Review Checklist

By using a code review security checklist, you can ensure that different codes are reviewed in a uniform manner. This is a fundamental part of a systematic inspection process, as it systematically outlines the existing security risks. Consider the following code review checklist template:

Functional Checks

Verify whether the code carries out the necessary functions and operates according to the existing requirements.

Make sure that the edge conditions and errors are appropriately handled.

Does the code function appropriately?
Have all requirements been fulfilled?
Are errors and edge conditions properly controlled?
Does the code behave according to the specifications?

Assessment of Readability & Easiness to Maintain

It is important to keep the code organized – it must comply with code standards and is easy to read.

This process implies that you need to ensure that the naming standards are followed, indentation is used properly, and comments are put in the right places in the code.

Has the code been organized in a proper way?
What naming standards are used?
Is the code formatted correctly?
Has the appropriate number of comments been placed in the code?

Error Handling & Logging Mechanisms

Ensure that the code is written with appropriate error handling and logging mechanisms to facilitate troubleshooting and debugging processes.

The following questions can be used to evaluate this aspect:

Does the code contain relevant error-handling mechanisms?
Are exceptions handled appropriately and at the right level?
Is logging performed to aid debugging and troubleshooting?
Are error messages descriptive and informative?

Security Checks

Verify if the code adheres to the established coding standards and whether it contains security vulnerabilities.

Below are the questions that can be used:

Does the code adhere to secure coding practices?
Are there any security vulnerabilities present?
Is the user input properly validated and sanitized?
Are authentication and authorization mechanisms implemented correctly?

Test Coverage

Ensure that the code has appropriate unit tests or integration tests that cover all mandatory features and edge cases.

Ensure that the tests pass and are updated.

Does the code have appropriate unit tests or integration tests?
Is the test coverage appropriate for all critical features and edge cases?
Do the tests pass and stay updated?
Is the code easily readable, highly structured, and maintainable?

Code Reusability & Dependencies

Check whether the code makes an appropriate use of the existing libraries, frameworks, and components, as well as whether all possible dependencies are managed properly.

Does the code make proper use of the existing libraries, frameworks, and components?
Are all possible dependencies handled properly?
Are all unnecessary dependencies and duplicate code parts removed?
Are all dependencies handled and have enough quality?

Compliance With Coding Standards

Ensure that the code is compliant with the coding standards of your organization and the project you work on.

Is the code in compliance with the coding standards required by the project?
Does the code make use of static analysis tools to check code standards?

Documentation

See if the code complies with some documentation for the complex code blocks.

Are the inline comments following the complex code modules?
Do the methods, functions and classes have docstrings or any other comments?
Is there any high-level documentation available for the complex modules?

Conclusion

In the increasing threat environment that we live in today, malicious actors abound, ready and waiting to pounce on any application vulnerabilities. Secure code review is one way of overcoming this problem. Expert Developers ensure that their code is hardened using the combination of secure coding practices and secure code review processes.