Secure code review is a procedure used to check for security problems in the source code being created and to ensure it has the appropriate security safeguards to stop an internal or external adversary from taking advantage of software vulnerabilities.  

In other words, a secure code review aims to determine whether the source code is strong enough to resist security threats and identify security flaws. It can also confirm that programmers follow according to your secure development standards and procedures.  

Penetration testing can assist you in taking a holistic approach to your application security, but a secure code review added to your testing strategy provides more thorough coverage. The OWASP Code Review Guide states, “A general rule of thumb is that a penetration test should not discover any additional application vulnerabilities relating to the developed code after the application has undergone a proper security code review.”  

Static application security testing (SAST) and dynamic analysis security testing (DAST) are two types of security audits for apps. Both strategies are complementary and used at various stages of the software development lifecycle to uncover multiple vulnerabilities. DAST, commonly called black box testing, finds flaws in operating applications. SAST makes it simple for developers to find and address problems as they code since it is deployed during the development process or in DevSecOps. Conducting a source code security analysis, or source code review, enables the early detection of vulnerabilities in software. 

Importance of Secure code review in cyber security 

Secure Code Review is used to find security flaws in software source code. It may be used to identify common code errors like buffer overflows, SQL injection, and cross-site scripting and is an integral part of the secure SDLC process.  

By locating and patching security flaws before threat actors can use them, safe code review strives to create trustworthy and secure software. During the review, trained security experts examine the application’s source code to check for any potential security holes. They then record their conclusions and offer suggestions for improvement. Any organization’s security strategy should include secure code review, which is crucial for ensuring safe software development.  

By following a set of best practices and guidelines or secure coding standards, developers and programmers can quickly weed out common weaknesses in their software. Secure coding practices must be used to eliminate frequently exploited software vulnerabilities and stop assaults. Additionally, planning for security from the start reduces possible long-term costs resulting from an attack that makes users’ sensitive data vulnerable. Despite the significance of writing secure code, there are several software vulnerabilities. The National Institute of Standards and Technology (NIST) vulnerability list search reveals that there have been 40,569 application vulnerabilities in the last three years. 

Usage of Secure code review 

Depending on the application’s criticality and the maturity of the AppSec program, security teams may implement safe code review at various stages of the SDLC or include it in an Agile development process. Similar to how frequent penetration testing adds more value to your security program, safe code review may considerably improve your secure software development lifecycle when implemented gradually and across the SDLC. The following are five critical times for using secure code review or static application security testing (SAST): 

1.During development: 

Integrating security scanning directly into the developer’s integrated development environment (IDE) is an excellent way to avoid adding security problems to your code while the product is being produced. It offers immediate feedback on secure coding best practices and is a perfect tool for assisting your teams in forming secure development habits. Finding and addressing vulnerabilities early in the development process guarantees they do not spread later. The cost of repairing a security flaw after it has been introduced into production, according to the National Institute of Standards and Technologies (NIST), can be up to 60 times more expensive than during the development cycle. 

 2.Pre-commit checks: 

Security flaws may be added when code from several developers is merged into one branch. Peer code reviews on pull requests often concentrate on functional defects; however, it is advised to run a fast security check additionally. This will aid in removing severe and urgent problems early in the chain. SAST tools with code collaboration features are available in all well-known code repositories. Because automated tools tend to be very loud, they should be carefully configured using limited rulesets to prevent harm to developer workflow. 

3.Post-commit: 

A thorough, secure code review is essential as source code is prepared to be included in a product’s final release to guarantee that it is free of security flaws. Continuous integration pipelines can incorporate SAST tools with a broader ruleset to report on current security vulnerabilities, which can then be filed into bug trackers or team backlogs.  

However, since tools are prone to false positives, breaking the build every time a security flaw is detected might not be practical. By modifying rulesets with the help of regular feedback from reported faults, static analyzers can be made better. 

4.Post deployment: 

Although implementing static analysis tools into the DevSecOps pipeline may appear simple, the rate at which new code is required to be produced makes it more difficult to detect and address all security concerns in each sprint or release. Regularly running SAST scans from production code repositories and scheduling safe code reviews into your annual calendar helps improve your security posture. Furthermore, these assist compliance with laws and guidelines such as PCI DSS and HIPAA.  

Your product security specialists, or “champions,” who can work directly with developers to patch vulnerabilities, should prioritize these scans to reduce noise and developer stress. However, only some companies have enough security analysts with knowledge of safe code review; thus, working with a secure code review provider is an option. 

5.Suspicion of malicious intent: 

This type of secure code review is more reactive. If you have reason to believe that malicious behavior is taking place within your organization, or if you have discovered a probable breach, conduct an on-demand code review scan to confirm your suspicions and locate the source of the violation. Keep in mind that your code review activities should support your company’s goals. The review should focus on finding points of interest (POI) in the code that can combine to build detrimental structures for malicious attack vectors. Look at the relationships between the various POIs and watch for instances of inversion of control, change, or other harmful techniques. 

The Secure Code Review Process 

The secure code review process is susceptible to a wide range of factors. Here are four areas that can have the most impact on your testing results: 

1.Define the Scope 

Depending on several elements, including the danger factors present, the coding languages used, the number of lines of code, and the program’s significance, each secure code review will have a different scope. Intensifying vulnerability mitigation measures and increasing the frequency of code review cycles will be essential. 

2.Custom Checklists 

Predetermined, distinctive checklists based on your product’s threat model are essential for the success of secure code reviews. Generic lists are only somewhat helpful since there isn’t a single, one-size-fits-all solution to application security. Making unique checklists for every piece of software may be quite time-consuming. To begin, think about using tools like the OWASP Application Security Verification Standard. Finally, ensure that your checklists are updated often. 

3.Automated Scanning 

Thanks to automatic vulnerability screening, manual testers may devote more effort to finding the most critical bugs in the code. Not every automated scanning tool is created equal; some are better than others, and some are intended to meet specific needs. Are the resources you currently have meeting your needs? When you scan, are you employing clever automation? Have a strategy to advance your technology and assess your tools to identify gaps. The following three qualities should be included in your automated scanning solutions: 

• The ability for customization 
• Connection with the CI/CD pipeline 
• Minimization of noise/false positives 

4.Manual Testing 

Human context is required to identify vulnerabilities that tools miss. Manual secure code review is crucial for sensitive, high-risk applications since they pose the most significant business risk. Humans can create custom scripts by using the necessary business logic and by approaching a secure code review from the viewpoint of an actual attacker. Additionally, false positives are a side effect of automation. A human triage of the vulnerabilities discovered in your code is a great asset; more than reading a report primarily comprised of raw data is required. 

Aspect of coding securely 

The Open Web Application Security Project (OWASP) has developed a collection of guidelines to assist developers in mitigating common software security flaws. For programmers to maximize application security. Here are a few of the most essential practices.   

1.Data input validation 

This covers a wide range of data source and input validation issues. Most cybersecurity dangers arise from external data inputs such as cross-site scripting, buffer overflows, and injection attacks. As a result, it is critical to define security practices that control which sources may be trusted and how data from unreliable sources can be validated. 

2.Authentication and password management 

 Limiting program access to authorized users is an effective method of preventing cyber-attacks and data breaches. The following are some recommended practices for authentication and password management:  

• Using a reliable system for password hashing  
• Password length and complexity requirements must be enforced.  
• Keeping authentication credentials on a dedicated server  
• Using multi-factor authentication 

 3.Access control 

Access control and authentication work together to guarantee that a malicious user cannot simply get access to the targeted system. As a general rule, it is advisable to implement a default-deny strategy, which implies that users who cannot provide authorization should be refused access. The code should demand periodic re-authorization for continued access to online applications with long login times. 

4.Keep it simple 

While it may seem odd, keeping your code basic and tidy is an excellent way to ensure security. This is due to the increased possibility of vulnerabilities creeping into the code in complicated designs. When creating software, developers should eliminate excessive complications and include just what is necessary. 

5.Cryptographic practices 

The above-mentioned safe coding standards highlight the significance of defining cryptographic solid techniques to protect secrets from the application user. To guarantee that any random values created as part of the cryptographic process are unguessable, they should be generated using an authorized random number generator. 

6.Error handling and logging 

Even the most well-written code is vulnerable to bugs. What matters is that when a mistake occurs, it is detected and corrected as soon as possible to limit its damage. The proper logging of all events that happen in the code is required for accurate error detection. Developers can use these logs to troubleshoot any faults that may have occurred. However, avoid including any confidential data in the error messages or records. 

7.Data protection 

The majority of cyber assaults aim to get access to sensitive data. As a result, it is unexpected that data protection is a significant part of safe coding requirements. Here are some helpful hints for efficiently securing data:  

• Compliance with the concept of least privilege states that code components should run with the fewest licenses required to fulfil the task.  
• Delete temporary or cached copies of sensitive data saved on the server regularly.  
• Passwords and connection strings should not be stored in clear text or any other non-encrypted format on the client side. 

8.Threat modelling 

It is difficult to protect yourself against unknown threats. This is why threat modeling is critical. It means identifying potential hazards and then developing countermeasures to avoid or reduce their occurrence. A threat modelling exercise should be conducted regularly to ensure no new threats are ignored. 

9.Beyond coding 

Implementing these suggestions will help fix the majority of vulnerabilities arising from the code itself. However, protecting the security of your code is an ongoing task that demands regular care. Other aspects that must be considered as part of a comprehensive approach to developing secure code include:  

• A “least privilege” system: Keeping access to any code on a need-to-know basis will help avoid injection attacks. This is especially difficult when hiring outsourced developers or development firms.  
• Defense in depth: Continue to stack defensive techniques when the code is promoted to production. Check that your runtime environments are just as secure as your code.  
• Quality assurance should be practiced: Multiple assurance programs like code reviews and PEN testing should be used to ensure quality.  
• Learn how to protect code using the Software Development Life Cycle (SDLC). Using an SDLC methodology will help you ensure security is applied throughout the development lifecycle. 

Conclusion 

As was said above, periodic secure code reviews are essential to preventing your business from falling prey to the next significant supply chain attack. Continuous static analysis checks should be incorporated into development environments, but adoption should be incremental to fulfill program goals with the most minor interference to developer productivity. SAST tool feedback, rule set changes, and manual code review and verification procedures can all help strengthen your application’s security.  

eInfochips, a leading global provider of product engineering and semiconductor design services, has extensive cybersecurity capabilities to help organizations safeguard themselves from various types of attacks. By finding the weaknesses in their systems and lowering the potential of attacks, organizations may benefit from our services including Hardware Testing, Firmware Testing, Secure code review, Secure SDLC, Debugging, vulnerability assessment, and security audit with OWASP, MITRE, ENISA, NIST and other security industry standards, regulations, and guidelines. Get in touch with us for your security needs. 

Reference 

https://www.threatintelligence.com/blog/secure-code-reviews 

https://vpnoverview.com/internet-safety/business/what-is-secure-coding/ 

https://entersoftsecurity.com/blog/source-code-review/ 

https://www.netspi.com/blog/executive/secure-code-review/importance-of-reviewing-source-code-for-security-vulnerabilities/ 

https://www.checkpoint.com/cyber-hub/cloud-security/what-is-secure-coding/