In today’s interconnected world, where data breaches and cyber threats are increasingly common, one of your top priorities should be to ensure the security of your software applications.
Fortunately, you can prevent many potential threats and vulnerabilities by writing better and more secure code and having a thorough code review process. But we know code reviews can be hard, especially when you’re unsure about the errors you should look for.
Today we’ll see 7 best practices for conducting effective code reviews having security in mind, allowing you to strengthen your software defenses. Let’s dive in!
7 best practices for security code reviews
#1 – Establish clear objectives and involve diverse reviewers
Before diving into a code review, you should establish clear objectives, defining the specific security goals you want to achieve through the review process. Setting clear objectives ensures that the review remains focused and targeted.
This is where having an SLA (Service Level Agreement) can help engineering managers prioritize work. Depending on your SLA, your goals can include identifying and mitigating common vulnerabilities such as SQL injection, cross-site scripting, or insecure direct object references.
You should involve a diverse set of reviewers to obtain the most comprehensive review possible. Ideally, assemble a team with individuals with expertise in secure coding practices and different programming languages. This diversity brings different perspectives and helps uncover a broader range of potential security weaknesses.
#2 – Sanitize and validate all input (even your own)
Today’s applications have everything from direct user input to interactions with different third-party inputs. As such, every input should be considered and treated as a potential threat – yes, even internal input controlled by your team.
To prevent your application from being vulnerable to content injection, validate and sanitize all input. Don’t forget to check on the format of the input, but also its range, size, file type, and file name. You should do this before the input is stored or used anywhere in your codebase.
#3 – Protect sensitive data
When sensitive data, like personal information or credit card numbers, is at play, you must take extra steps to protect those data. Besides using proper storage, you must also guarantee that you don’t expose those pieces of information via autocompletion or data transmission.
Don’t forget to use proper encryption, like strong 2-way encryption or cryptographic hashing algorithms. Keep regularly reviewing the algorithms you use to guarantee they are still secure. And, of course, if you need to transfer sensitive data, check if the connection is secure.
#4 – Implement secure authentication
Authentication allows you to verify if a user or entity is who they say they are. However, the best practice here is to assume they are not who they say until they have provided the right credentials to prove it.
You should also enforce password complexity (we know about it – at least one uppercase character, one lowercase character, one digit, one special character, and a specific length). For users, it might not be easy to remember, but that’s why password managers exist as well.
#5 – Give the least privilege possible
Some people should have different levels of access. Authorization allows you to ensure that a user or entity has the right to access specific information or perform particular actions. Your codebase should not be giving more access than is necessary.
As such, as a rule of thumb, you should follow the principle of least privilege, which states that every module must be able to access only the information and resources they need for its legitimate purpose. This means that you’ll give only the minimum privileges and permissions they need to achieve their goal.
#6 – Automatically test your code with static analysis tools
Leveraging automated code analysis tools that can focus on security will significantly enhance the efficiency and effectiveness of code reviews.
By statically looking at your code, these tools will quickly identify common security-related issues and help pinpoint potential vulnerabilities. For example, the Codacy Quality tool can highlight issues like SQL injections and Cross-Site Scripting (XSS).
Codacy uses an early feedback system that alerts you as soon as it finds potential security risks in the code. As such, it helps your team write high-quality code that isn’t susceptible to security risks. Plus, Codacy integrates directly with your workflow, helping you save time.
Automatically testing your code can also help find issues in code your team didn’t write, like third-party libraries and frameworks. They are great for saving time, and there is no need to reinvent the wheel when a library already exists. However, we still need to ensure there are no known vulnerabilities in the entire dependency tree of our software.
#7 – Stay on top of emerging threats
Staying updated on emerging threats and attack techniques is essential in the ever-evolving software security landscape. Encourage code reviewers to keep educating themselves about the latest security vulnerabilities and countermeasures. Reviewers can effectively identify new risks and incorporate appropriate security controls during code reviews by staying informed.
🎥 [Webinar] Are you meeting SLA for your most critical security issues?
Join Mike Khusid, VP of Product at Codacy, in discussing how SLA tracking can help engineering managers prioritize work on security issues and best practices to shift-left the resolution of those issues.