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As operations have largely migrated to cloud environments, business IT is becoming more complex. One recent study found that 65% of IT leaders customize apps before deploying them for team use, and nearly half develop their own apps in-house. All in all, the volume of apps in use in the average enterprise continues to grow, having blossomed to over 1000 in the past year.

Along with the dependence on apps—whether customized, developed for internal use, or created to offer to the wider market—comes the imperative to undertake app security testing. Because they sync with databases and networks containing sensitive data and because rendering them useless can cause serious business operational damage, apps are popular vectors for cyber attacks. Threat actors can exploit bugs and security weaknesses in apps to intrude into networks, steal data, spread malware, and perform other malicious or harmful actions.

To ensure app security, it is important to undertake thorough testing, specifically through Static Application Security Testing (SAST), Dynamic Application Security Testing (DAST), and Interactive Application Security Testing (IAST). These three key types of application security services can work together or independently to ensure your company's software is safe.

It wasn't long ago that testing for app security was performed manually, which involved cybersecurity teams examining code bases individually in a time-consuming and exhaustive process. At present, new testing methods have been developed, and they ensure efficient security evaluation to keep up with the modern threat landscape.

Static Application Security Testing

SAST focuses on inspecting static source codes to reveal security deficiencies. It examines the non-compiled code in search of problems like mathematical errors, syntax problems, invalid references, reference insecurities, and input validation issues. It can also detect code injection vulnerabilities, access control issues, and poor security practices when it comes to API usage.

The key approach in SAST is "white box testing," whereby the testers inspect the inner operations of an application. This includes the scrutiny of the code, infrastructure, and integrated systems. White box testing is important in implementing a Continuous Integration/Continuous Delivery (CI/CD) development pipeline, as it ensures that apps go through a comprehensive security review before they are deployed.

Static Application Security Testing is also the underlying testing method used in Software Composition Analysis (SCA), a process that enables organizations to undertake a systematic inventory of third-party app components. SCA emphasizes the inspection of third-party elements, from proprietary to open-source. It identifies security weaknesses and risks that may not have been covered by the usual SAST process, reducing the software attack surface and improving compliance.

Dynamic Application Security Testing

DAST is app security testing that is undertaken while an application is running. It aims to spot vulnerabilities, security issues, and other problems that only arise while an application is in active use. It is designed to examine an application's security aspect in real-world situations, especially as it operates under various network conditions, configurations, and user inputs.

DAST entails proactive vulnerability identification and continuous monitoring. It also factors in compliance requirements. It is not a one-off testing process. Organizations need to undertake DAST from the moment the app becomes executable to the time it is ready for sunsetting.

Compared to SAST, DAST can detect more vulnerabilities because it scans the app while it is in operation. Not all problems can be detected, even with the most thorough and comprehensive of code reviews. DAST's real-world security testing ideally finds issues before an app is deployed so that these issues can be addressed while the app is still in the relatively safe confines of development environments.

It is important to emphasize, though, that DAST is not an alternative to SAST. Rather, it is a complementary testing method. Organizations may deem it enough to use SAST for basic apps, but when it comes to more complex applications, it makes sense to undertake dynamic testing as well.

Interactive Application Security Testing

IAST brings together the benefits of SAST and DAST to achieve real-time feedback on the security weaknesses of applications. It is a valuable tool for DevOps teams, as it facilitates the shift-left approach and improves developer productivity. Additionally, it reduces false positives that tend to be inevitable in conventional SAST and DAST.

Interactive Application Security Testing is run from within the application server, which enables it to examine the compiled source code and execute dynamic app inspection during runtime. It introduces IAST agents into the application code that monitors the app's behavior and interactions with environmental factors. It performs real-time analysis to spot a variety of vulnerabilities, including cross-site scripting, SQL injection, and cross-site forgery.

Once a vulnerability is detected, the security team immediately gets notifications that include details about the nature of the vulnerability, its location, and the possible steps for remediation.

Applicability of the Different Testing Methods

These different testing methods have different purposes for different stages in the app lifecycle. SAST is for early-stage testing, including the evaluation of the app code during integration with CI/CD pipelines. DAST is used when apps are ready for execution but before deployment. IAST is usually implemented by enterprises after deployment as a continuous monitoring solution.

There are also app security testing regimes that are designed to employ SAST, DAST, and IAST throughout the app security evaluation process, as in the case of Mobile Application Security Testing (MAST). This testing method intended for mobile environments uses three testing methods as well as jailbreaking, data leakage detection, defense against malicious Wi-Fi networks, and other approaches suitable for mobile software.

MAST involves client-side, server-side, and platform-specific testing that includes code analysis, network traffic assessment, reverse engineering, API testing, and data storage and transmission evaluation.

Moreover, it is worth mentioning that these three testing methods have become the fundamental basis for the development of RASP, or Runtime Application Self-Protection. Considerably more advanced, RASP is sometimes described as the next generation of SAST, DAST, and IAST.

In addition to examining source code and analyzing the security issues of an app while it is running, RASP can also intervene if a security vulnerability is being exploited. It can terminate a session, for example, if there is an ongoing data theft or an attempt to transmit malware. In other words, it does not only test the security of apps; it can provide active protection.

In Conclusion

Application security testing is a must for modern organizations, especially with the inescapability of using apps in day-to-day operations. The enterprise IT ecosystem is increasingly becoming complex with the use of a multitude of apps and the introduction of new smart and connected devices, which complicate cybersecurity needs. It is important to be proficient in addressing the threats aimed at apps and to pay ample attention to the need to ensure security before any application is deployed.