Best Secure Coding Practices for Software Developers

During the development process, software developers must use good security practices to avoid cases of having vulnerabilities and exploits in the future. It ensures we have secure applications and websites. Following all the practices at the earlier stages is also cheaper than waiting until something bad happens for you to start implementing. It is the role of everyone on software development teams to ensure they follow the practices throughout the process.

According to CompTIA, businesses lost more than $12 million to hackers during the year 2022, most of them through phishing and ransomware. They target some of the biggest industries: retail, education, healthcare, energy, and finance. This guide will look at some secure coding practices for software development.

10 Best Secure Coding Practices for Software Developers

Let us discuss some of the ways one can use to ensure their application is secure. Most practices involve a lot and may need you to work as a team to achieve all of them. The practices are as follows:

1. Input validation

Input validation ensures all the data input by the users meets the right criteria and removes all characters that may seem malicious. Developers should implement it on all websites that accept inputs and those that do not. It is also important when dealing with third parties like APIs and other sources.

Correct input validation prevents attacks like SQL injection, Buffer overflows, memory leakage, and XSS attacks and improves user experience. Some other methods for implementing input validation include:

Validating all the data types needed, the data ranges and lengths, redirects values, etc.
Create rules, i.e., whitelisting for setting the only allowed characters, blacklisting to prevent certain characters during input and formats, i.e., include @ in emails.
Do data validation for the servers and other sources like databases.

2. Output encoding

Output encoding involves changing all the special characters into another format that is not dangerous to the interpreter. It mainly protects websites and applications from cross-site scripting. Encoding works according to different programming languages, i.e., Java uses OWASP Java Encoder .NET uses AntiXssEncoder, etc. You can implement output encoding using the following methods:

Ensure that you encode all the data from the client side, i.e., using HTML entity encoding.
Carry out encoding for all the files from JSON and XML.
Sanitise all the data that comes from all the queries like SQL and LDAP.

3. Password management and authentication

Password and authentication management is one of the toughest tasks software developers handle. They are among the essential practices that limit hacking risks. It reduces cases of cyberattacks among users, which could affect your company. Some of the common ways of doing password management and authentication include:

Use different authentication controls for the pages, servers, and resources.
Use POST to transmit all the authentication messages.
When asking for a password from the user, ensure it is strong by asking for a certain length, i.e., please use more than ten characters.
Improve your password policy by having a strong policy that can give hackers a hard time when they try to crack the passwords, i.e., require all the users to input passwords with a mix of numbers, alphabets, and special characters.
Show all authentication errors and avoid indicating the cause of the error, i.e., invalid email, but instead indicate both of them, i.e., wrong password or username.
Using TLS certificate and TLS authentication when performing TLS handshake.
In case of password reset, ensure the reset links have an expiry time and add other precautions like notifying the user of a reset, avoiding reset within a certain period like a one-day timeframe, avoiding password reuse, etc.
Use multi-factor authentication for users who login into their accounts. It protects users from someone else accessing their accounts without their knowledge.

4. Protecting the software code

Ensure you protect how you handle your sensitive information. Most of the practices will help you protect your code from hackers and for this, you can get Code Signing certificate. Such certificate allows developers to sign their code with hashing and encryption and ensures end users that their software is safe to download. Apart from this, some of the ways on how to protect sensitive information include:

Configure your TLS well and ensure all your domains use a valid certificate.
Use character encoding for all your TLS connections.
Remove sensitive information from HTTP referrers when dealing with external applications.

5. Use of sessions

It involves handling different sessions or requests between a single user or entity across a website or service over HTTP and HTTPS. Ensure you secure all the user’s sessions, especially when it happens against their request. Most applications and websites use session tokens (session IDs) to control the user’s session on a website or application. You must have ways of controlling the requests and responses.

Most software developers use session cookies to put the user’s data in a memory area and delete it after the session closes. Some common attacks on sessions are session hijacking and fixation, where hackers steal and use the session details for their benefit.

Some of the best ways to use for session management include:

Using the Secure flag ensures your website or application only transports data across HTTPS, not HTTP. Extend the flag to the session’s cookies to prevent your JavaScript from accessing it.
Do proper configuration of the session cookies. Ensure they are long, have an expiry duration, and are unique. The expiry duration can be around 20 minutes using the Max AGE and Expiry attributes. Also, remember to restrict how domains access the cookies using domain attributes.
Make a habit of generating cookies during every action, i.e., create a cookie every time a user provides logins and logouts, provides details, and during any visit. When the session ends, or there is no activity, end the session.
Use well-detailed algorithms to control session generation and identifiers during the session management processes.

6. Following coding standards

Software developers must follow several coding standards to produce quality code free from bugs. The standards are not hard to implement and may vary depending on different programming languages. For instance Python, you must follow the indentation and implement PEP 8. Performing reviews prevents common attacks like SQL injection, cross-site scripting, etc.

Some of the best coding practices across all programming languages include the following:

Verify all your libraries, code, and files using hash or other related methods.
Ensure there are several software updates, and remember to protect the code using signatures, encryption, and cryptography.
Perform code reviews. Test different aspects of the application and website by ensuring the code is well written. When using software methodologies like DevOps, most security issues get fixed during the earlier stages of development.

There are automated tools that your company can buy to help speed up the whole process. Some tools include Burp Suite, GamaScan, Acunetix, etc. Most are free, while others have paid versions.

Comment on your code well and ensure proper documentation for all the design decisions.
Ensure you check for any threats that may affect your software or application. After getting all the threats information, make decisions and put enough effort to ensure, the security risks are worked on.

7. Error Handling and Logging

When building any software, some bugs come with it. Most bugs can lead to vulnerabilities, but that is when you use logs and error handling to minimize them. Error handling varies, and most developers know how to do it. Teams ensure they have clear documentation on handling them to achieve the best coding standard. Some of the best practices include:

Avoiding revealing important messages in cookies, sessions, and account information.
Limit who can access the logs and reduce it to the admin level.
Analyse all the logs from validation failures, system exceptions, administrative features, control failures, backend, cryptographic failures, and TLS connections.
Use different logic when handling code.
Avoid storing sensitive information under your logs.
Ensure the log details has all the event data.

8. Limiting access

Access control determines those who can access an application or website resources using permissions and the least privilege principle. Developers must create policies that govern actions users can take on the resources. Sometimes it is beyond the users, and you can limit devices and processes. It controls the processing, viewing, and use of different resources.

There are several types of access. The common ones include physical, network, operating systems, and restricted access. You can use different levels to limit those accessing other parts of the software or application.

Using the least principle privilege method is one of the ways to control access. It limits people who can access code and other parts of an application according to their role. For example, a customer service agent cannot access payroll officer data. It manages the server using different logic. Some programming languages like Java and .NET provide the developer with more functionalities to control how the code runs.

Other ways of controlling access include:

Disable all the accounts when there are changes in the company from roles, processes, or changes of employment status.
Ensure your code uses specific privileges and drop the ones not in use.
For cloud platforms like AWS, use AWS IAM for access management by defining the three purposes: user, group, and roles.
Implement integrity confirmation and encryption on the server side if some state data gets stored for the client.
Perform restriction by using the least privilege principle, i.e., by enabling who can see the URLs, services, application data, user attributes, functions, data attributes, object references, etc.
When dealing with service accounts that get support from external applications, ensure to provide them with little privilege.

9. Securing your database

The database carries all the contents of your application and website. Hackers target websites using different methods like SQL injection, which can lead to table dropping and affect the app’s behaviour. Some of the practices for securing your database include:

Use parameterized queries when writing your database code.
Close all the connections as fast as possible.
Avoid using the default usernames and passwords; instead, create a strong password and username.
Type your variables strongly and ensure to implement validation and encoding.

10. Cryptography

It involves using different algorithms to prevent messages from being deciphered. There are different cryptography measures software developers can use. It promotes strong authentication and improves integrity and confidentiality. Some of the common cryptography practices used include:

Generating random names, strings, and numbers gives hackers a hard time.
Storing all the access keys in a better place.
Avoid using key management, but instead, use options like DPAPI.
Using hashing algorithms and strong encryption.
Using modules that comply with some common standards, i.e., FIPS 140-2.
Implement your modules to support your data when in all states from in motion, storage, and transit.

Conclusion

There is high demand for mobile applications and websites. Secure coding practices must be compulsory for all companies building websites and applications. It eliminates the chances of having issues for both your customers and the company reputation. Following the practices shows you care for the user and will give hackers a hard time when they try to access your services illegally. Implementing the above practices will eliminate all the risks that come with vulnerabilities.