What Are the Best Practices for Mobile App Security Testing?

The modern tech user spends approximately 3 hours and 15 minutes on their mobile device daily, with research showing that individuals check their devices up to 58 times a day. In the United States alone, 70% of all digital media time comes from apps and mobile apps were estimated to garner over $935 billion in revenue in 2024.

While mobile apps are most commonly used for communication and entertainment, many also use them for business purposes, banking, or even as healthcare support.

These apps deal with loads of sensitive information, so keeping them safe from potential threats is a top priority. That’s where mobile app security testing comes in—it helps protect apps from vulnerabilities that could put user data and trust at risk.

In this article, we’ll break down the basics of mobile app security testing, what it is, why it matters and what are the best practices to adopt.

What is mobile app security testing?

Mobile app security testing is all about simulating how a hacker might try to break into an app. To do it right, you need to start by understanding what the app does and the type of data it handles. From there, a mix of static analysis, dynamic analysis, and penetration testing works together to uncover vulnerabilities that might otherwise slip through the cracks. Here's how it typically goes:

• Dive into the app to see how it stores, sends, and receives data.
• Break down any encrypted parts of the app.
• Decompile the app to examine its underlying code.
• Use static analysis to spot weak points in the code.
• Take insights from reverse engineering and static analysis to guide dynamic testing.
• Perform dynamic analysis and penetration testing to see if security measures like authentication and authorization are holding up.

There are plenty of free and paid tools for testing apps, but no single tool can do it all. That’s why combining static and dynamic testing with a manual review is the best way to cover all the bases.

Think of security testing as a pre-launch safety check. It ensures the app’s security measures work as intended and catches bugs developers might not have anticipated—especially those tricky edge cases. Testing digs into both the app’s code and its configurations in an environment similar to production, so potential issues can be found and fixed before the app goes live.

Why do you need mobile app security testing?

Mobile app security testing is crucial for several reasons, all aimed at ensuring your application is safe and trustworthy. Mobile devices typically have weaker security measures compared to traditional computing systems, making them attractive targets for cybercriminals.

First, it helps spot vulnerabilities early, so developers can address any flaws before releasing an app susceptible to malicious attacks. Once these vulnerabilities are identified, security testing plays a key role in fixing them, ensuring the app is robust and that users' data stays protected. Compliance is another essential aspect, especially since many apps handle sensitive personal or payment information. By adhering to security standards, businesses can avoid legal and financial repercussions. 

Ultimately, thorough security testing minimizes the risk of data breaches, theft, or loss of confidential information, giving users peace of mind and keeping the reputation of both your app and your company intact.

What are some common mobile app security vulnerabilities?

To understand the importance of mobile app security testing, let’s dive into three common vulnerabilities in mobile applications: insecure data storage, memory leaks, and supply chain issues.

Insecure data storage

Insecure data storage happens when sensitive information like user credentials, financial data, or personal details isn’t handled properly within the app. For example, if your database credentials aren’t set securely or your cookie storage lacks proper encryption, attackers can easily exploit these weaknesses.

Consider what might happen on a rooted device or with a reverse-engineered app. If security enforcement is weak, an attacker could gain access to your database, putting sensitive information at serious risk.

To combat this, encrypt your data, implement strong authentication mechanisms, and perform regular security audits. Following best practices for data handling can go a long way in safeguarding against unauthorized access.

Memory leaks and corruption

While apps built with languages like C, C++, or Objective-C can deliver impressive performance, they’re also more prone to memory management issues such as leaks and buffer overflows. These problems can lead to system instability or make your app vulnerable to attacks like denial-of-service (DoS).

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To prevent this, adhere to best programming practices and use tools like static application security testing (SAST). SAST scans your code to identify memory leaks or buffer overflow risks, enabling you to address these issues before they become threats.

Supply chain vulnerabilities

Supply chain vulnerabilities stem from insecure third-party components like libraries and frameworks. These can harbor hidden bugs or even malicious code, which attackers can exploit. In some cases, malicious code within a third-party tool might activate once integrated into your app.

Here’s a recent example: earlier in 2024, tech company Dell suffered a data breach which resulted in stolen data for some 49 million customers. 

To protect your software supply chain, rigorously test third-party components and stay on top of security updates and patches. Adopting a shift-left approach—addressing security early in development—can also help identify and mitigate these risks proactively. This way, you can ensure that third-party elements enhance your app rather than compromise it.

By understanding and addressing these vulnerabilities, you can create a safer, more resilient mobile application for your users.

Common mobile app security threats

The first step to effective mobile app security testing is understanding the risks your app might face. Here are some common threats that mobile apps encounter:

• Malware attacks. Malicious software, or malware, can sneak into devices through apps. Once inside, it can steal sensitive data or even cause significant damage to systems.
• Unauthorized access. When apps rely on weak authentication methods, they leave the door open for attackers to gain access to sensitive information, putting user privacy and security at risk.
• Data leakage. Poorly handled data storage or transmission can lead to leaks, exposing personal or financial details to prying eyes.
• Insecure communication. Without proper encryption, data transmitted through your app becomes vulnerable to interception, making it an easy target for attackers.
• Code tampering. Attackers may alter an app’s code to introduce harmful vulnerabilities or hidden malicious functions, jeopardizing both your app's security and its users' trust.

Recognizing these threats is a crucial step toward building a secure mobile app that protects both user data and your reputation.

What are some methodologies in mobile app security testing?

Mobile app security testing can be divided into these three main methodologies: static application security testing (SAST), dynamic application security testing (DAST), and interactive application security testing (IAST). Each of these methodologies are important but they play a different role. Let’s break them down.

Static application security testing

Static application security testing (SAST) examines your mobile app in a non-running state, focusing on its source code, bytecode, or binary code. By using SAST, you can spot security issues, weaknesses, and potential flaws early in the development process, giving you the chance to fix them before your app goes live.

Incorporating SAST from the start and throughout development is key. It helps uncover structural and logical issues when they’re still manageable and cost-effective to address. On the flip side, skipping or delaying SAST can leave serious flaws undetected, which might surface later when fixes are more complicated, time-consuming, and costly. Worse, these delays can throw off your app's publishing schedule. In short, SAST is your best ally for a secure and efficient development process.

Dynamic application security testing

Dynamic application security testing (DAST) takes a different approach from SAST by evaluating your app in a running state. Instead of analyzing static code, DAST tests your mobile app as it operates on a real device, offering insights into how it functions from an end-user's perspective.

DAST focuses on identifying security issues that only emerge when the app is running, such as:

• Data exposure during transmission.
• Authentication and authorization flaws.
• Server misconfigurations.
• Unintended dynamic behaviors in the app.

Since DAST examines compiled code in a runtime environment, it’s typically performed later in the software development lifecycle (SDLC). This testing approach is particularly useful for understanding your app from an attacker's perspective—someone without access to your source code—helping you spot vulnerabilities before the app goes live.

Once vulnerabilities are identified, you can decide how to address them based on their severity. Critical issues may require immediate fixes, while less urgent ones can be resolved in a future release. This balance ensures both app security and timely delivery.

Interactive application security testing (IAST)

Interactive application security testing (IAST) blends the best of SAST and DAST into one dynamic testing approach. Unlike traditional methods, IAST works while your app is running by using instrumentation—software libraries embedded into the app’s code. These libraries actively monitor the app’s behavior and interactions during runtime, providing deeper insights into potential vulnerabilities.

Typically performed during the testing or QA phase of the software development lifecycle (SDLC), IAST has access to key aspects of your app, such as:

• Code structure.
• Dataflow and control flow.
• System configuration details.
• Back-end connections.

What sets IAST apart is its ability to pinpoint the exact location of vulnerabilities in your code while the app is running. This combines the precision of SAST with the real-world context of DAST. For instance, while DAST may flag a vulnerability without much detail, IAST provides clear, actionable insights to help developers identify and fix the issue more efficiently.

By offering a comprehensive view of your app’s security in real time, IAST ensures a faster, more effective resolution of vulnerabilities, making it a powerful method for delivering secure, reliable applications.

Types of mobile app security tests

To protect your app thoroughly, it's important to use a combination of security tests. Each test targets different aspects of security, and together they form a strong defense against potential threats. Key types of security tests include:

• Vulnerability scanning
• Penetration testing
• Risk assessment
• Security posture assessment
• Authentication and authorization testing
• Encryption testing

Each of these tests plays a unique role in identifying weaknesses and strengthening your app’s security. Let’s break them down.

Vulnerability scanning

Vulnerability scanning involves using automated tools to check your app's ecosystem for potential security risks. These scanners focus on identifying known vulnerabilities, especially in software dependencies that could be exploited in an attack.

In addition, vulnerability scans can catch overlooked loopholes in your app’s code by comparing it against a list of common vulnerabilities and their characteristics. When a match is found, the scanner reports the issue to the developers or the quality assurance (QA) team so they can address it.

This process helps ensure that any weak spots are identified and fixed before they can be exploited.

Penetration testing

Penetration testing (also known as pen testing) is a method where ethical hackers simulate real attacks to test an app’s security and uncover weaknesses. Unlike vulnerability scanning, which is an automated testing process, penetration testing relies on human expertise to actively attempt breaking into the app and discovering potential attack points.

One key advantage of penetration testing over vulnerability scanning is that it typically provides more accurate and realistic results. While vulnerability scans may sometimes produce false positives, the threats identified in penetration tests are actionable. These tests not only pinpoint security flaws but also offer detailed insights into their exact locations and how they could be exploited in real-world scenarios.

Risk assessment

Risk assessment is the process of identifying and evaluating all the people, processes, and tools involved in an app’s ecosystem to understand the risks they pose in the event of a cyber attack. This includes cataloging assets, recognizing potential threats, and analyzing how vulnerabilities could be exploited.

The goal is to determine the severity of each risk—how it might impact your operations, reputation, and finances—and the likelihood of it happening. With this information, teams can get a clear picture of the overall threat landscape and make smarter decisions to strengthen their security.

Security posture assessment

Based on the results of a risk assessment, teams can prioritize potential risks and create specific strategies to strengthen their security. These strategies might include improving authentication methods, applying software updates and patches, developing incident response plans, or setting up continuous monitoring tools for better oversight.

Security posture assessments often involve compliance auditing to make sure the organization’s security practices meet the required regulatory and industry standards. This helps avoid legal and financial penalties by ensuring compliance with security obligations.

Posture and risk assessments go hand in hand and can be complemented by other forms of security testing. Together, they all aim to identify security gaps, prevent attacks, and reduce risks.

Authorization and authentication testing

Weak authentication and authorization can open the door for attackers to gain privileges, potentially allowing them to disrupt systems or steal user data.

Imagine a shared directory. Should students be able to access answer files meant only for teachers? Or could someone bypass a security question altogether? These are the kinds of scenarios you should consider when testing your app’s authentication and authorization protocols.

Effective authorization and authentication testing involves several key aspects:

• Ensuring strong password policies to protect against brute-force attacks.
• Verifying secure session management to prevent session hijacking or reuse of session IDs.
• Testing multi-factor authentication (MFA) to add an extra layer of security for accessing sensitive data.
• Properly implementing roles and permissions so users can only access what their privileges allow.

DAST can play a significant role here. It simulates attack scenarios to evaluate how well your system defends against unauthorized access attempts, helping you identify and fix weaknesses before they become real threats.

Encryption testing

Strong encryption algorithms make it much harder for attackers to access your app and steal sensitive information. However, simply encrypting the authorization process isn’t enough—you need to apply encryption across all layers that handle sensitive data.

Take the transport layer (layer 4) of the OSI model, for example. This layer manages communication between network applications, making it a potential target for attackers. Without proper encryption, hackers could eavesdrop, intercept data, or leak communication details, putting your app and its users at risk.

To ensure your app uses robust encryption practices, leverage SAST. This helps verify that strong encryption mechanisms are in place, keeping your application and its data secure from potential threats.

How to perform mobile app security testing

Mobile app security testing is a detailed process that includes planning, using different testing methods, analyzing the results, and applying fixes. The aim is to find vulnerabilities before attackers can exploit them. Here's a step-by-step guide on how to effectively conduct mobile app testing.

1. Planning and requirements analysis

Define security objectives and scope

• Identify assets. Figure out what data and features in your app need the most protection.
• Set security goals. Set clear goals, such as protecting user data, ensuring transaction integrity, and complying with regulations.
• Determine testing scope. Decide which components of the app—like backend servers, APIs, and third-party integrations—will be tested.

Understand the app architecture

• Platform specifications. Be aware of the differences between iOS, Android, and other platforms.
• Data flow diagrams. Create diagrams to map out how data moves within the app.
• Third-party components. Make a list of all external libraries, SDKs, and APIs used in the app.

Compliance requirements

• Regulatory standards. Refer to any relevant laws, such as GDPR, HIPAA, or PCI DSS.
• Industry guidelines. Refer to security standards, like the OWASP Mobile Application Security Guide.

2. Setting up the testing environment

Prepare testing devices

• Real devices vs. emulators. Use a combination of physical devices and emulators to test a variety of scenarios.
• Rooted/jailbroken devices. Include these to see how the app behaves on compromised devices.

Configure network settings

• Proxy tools. Use tools like Burp Suite or OWASP ZAP to capture and analyze network traffic.
• Simulate network conditions. Test the app under different network conditions (3G, 4G, Wi-Fi, no connectivity).

Access to source code

• Obtain source code. You'll need access to static analysis and code review.
• Ensure legal compliance. Make sure your testing activities are authorized and follow legal requirements.

3. Conducting SAST

Automated code scanning

• Static analysis tools. Use tools like Fortify, SonarQube, or MobSF to scan the code for vulnerabilities.
• Configuration files review. Check for misconfigurations in manifest files (e.g., AndroidManifest.xml, Info.plist).

Manual code review

• Review critical sections. Focus on sensitive areas like authentication, authorization, data handling, and encryption.
• Check for hardcoded secrets. Look for hardcoded API keys, passwords, or cryptographic keys.

Identify common vulnerabilities

• Injection flaws. Look for SQL, OS command, or other injection vulnerabilities.
• Insecure data storage. Ensure sensitive data isn’t stored insecurely on the device.

4. Performing DAST

Runtime testing

• Functional security testing. Test how the app behaves under normal and abnormal conditions.
• Input validation. Check how the app handles unexpected or malicious inputs.

Network communication analysis

• Intercept network traffic. Use proxy tools to inspect the data being sent over the network.
• SSL/TLS verification. Ensure SSL/TLS protocols are properly implemented to prevent man-in-the-middle attacks.

Session management testing

• Session hijacking. Test for vulnerabilities that could allow session hijacking.
• Token expiration. Verify that session tokens expire correctly after inactivity or logout.

5. Executing penetration testing

Simulate attacks

• Black-box testing. Perform tests without knowledge of the app’s internal workings to simulate an external attack.
• Gray-box testing. Test with partial knowledge to uncover vulnerabilities not apparent in black-box testing.

Exploit known vulnerabilities

• Use of exploitation tools. Use tools like Metasploit to try exploiting discovered vulnerabilities.
• Privilege escalation attempts. Attempt to gain unauthorized access or higher privileges within the app.

Perform platform-specific testing

• Android security testing. Look for issues like improper use of intents, insecure activities, or exposed components.
• iOS Security testing. Assess security around the keychain, plist files, and app transport security settings.

By following these steps, you can ensure that your mobile app is well-tested for vulnerabilities and security flaws, helping to protect both your users and your organization.

Best practices for effective mobile app security testing

Ensuring robust security for your application starts with following a set of best practices. Let’s break them down in more detail:

Integrate security early

The earlier you include security testing in your development process, the better. By addressing vulnerabilities at the design or development stage, you can resolve issues before they grow into major problems. This approach, often called “shift-left security,” helps catch potential flaws when they’re easiest—and cheapest—to fix.

Commit to continuous testing

Security isn’t a one-and-done task. Regular assessments are essential to identify new vulnerabilities that could arise due to code changes, updates, or evolving threats. Make continuous testing a part of your development cycle to maintain your app's resilience over time.

Leverage comprehensive tools and techniques

Relying on a mix of tools that offer both static (SAST) and dynamic (DAST) analysis is key to uncovering a wide range of vulnerabilities. Static analysis helps you identify flaws in the code itself, while dynamic testing simulates real-world attacks in a running environment. Using tools with these combined capabilities ensures more thorough coverage.

Stay ahead of emerging threats

The cybersecurity landscape is constantly evolving, with new threats and tech fails emerging every day. Staying informed about the latest security trends, attack methods, and vulnerabilities is crucial. Regularly update your testing strategies to address these changes and ensure your app remains protected.

Educate your development team

Security starts with the people building your application. Equip your developers with the knowledge to write secure code by training them on best practices, common vulnerabilities like the OWASP Top Ten, and strategies to mitigate risks. A well-informed team can prevent many security issues before they even arise.

By integrating these best practices into your development workflow, you can create a proactive security culture and significantly enhance your app’s defense against potential threats.

The bottom line

In today's digital landscape, mobile app security testing is more important than ever. With their broad user base, mobile applications have become prime targets for cyber threats, making it essential to protect both users and businesses from potential risks. Issues like insecure data storage, memory leaks, supply chain vulnerabilities, and weak authentication can not only compromise sensitive information but also erode user trust.

By understanding the principles of security and implementing effective testing strategies, organizations can build more resilient applications. Leveraging advanced tools, and techniques, and adhering to best practices—like automating security scans throughout the development cycle—ensures vulnerabilities are identified and resolved quickly. This proactive approach strengthens an app’s security, safeguards user data, and promotes a smoother, more efficient development process. Ultimately, prioritizing security testing fosters trust and reliability in your application, benefiting both users and businesses alike.

Is your app secure enough for your users? Contact us today to learn how our mobile app security testing can help you identify vulnerabilities, safeguard sensitive data, and build trust.