How to Perform Mobile Application Penetration Testing?

Mobile applications have come a long way since the early 2000s. Today, they’re not just confined to smartphones — a single iOS app can seamlessly work across your phone, smartwatch, and laptop. This interconnectedness is great for convenience, but it also greatly increases security concerns. 

This entails a shift towards proactive security measures like mobile application penetration testing. Pentesting simulates real-world attack scenarios, emulating hackers’ behavior to target various aspects of your mobile app, including network security, client-side and server-side vulnerabilities, and API security.

Data breaches in mobile applications can have serious consequences for you, like losing access to accounts, identity theft, and even financial fraud. They are part of a larger ecosystem that constantly interacts with network infrastructure, servers, and data centers, contributing to an expanded attack surface. 

What is Mobile Application Penetration Testing?

Mobile app penetration testing finds vulnerabilities in an iOS or Android mobile application’s cybersecurity posture. It is the practice of examining mobile apps to find, classify, and fix vulnerabilities before they are maliciously exploited. 

It helps tighten the security levels for sensitive data and different app functions to provide a well-protected app that protects users and admins alike. Code, architecture, data storage, network connectivity, and authentication methods are all tested throughout this procedure.

Importance of Mobile App Pentesting

• Identify and fix vulnerabilities: Don’t wait for a data breach to discover weaknesses in your app. Mobile pentesting helps you identify and address potential issues such as insecure coding practices, logic flaws, misconfigurations, and outdated dependencies before they can be exploited.
• Protect user data: Mobile apps often store sensitive user information like login credentials, financial details, and personal data. Pentesting helps ensure this data is secure from unauthorized access by exploiting weaknesses in data storage mechanisms, encryption protocols, and access control measures to find areas where user data might be at risk.
• Maintain user trust: Data breaches and security vulnerabilities can greatly impact customers’ trust in your app. Pentesting demonstrates your commitment to user data security to build trust and confidence in your brand, leading to a more loyal user base and increased engagement with your app.
• Compliance: Many industries have regulations regarding data privacy and security. A mobile pentest helps ensure your app complies with relevant regulations, such as GDPR in Europe and HIPAA in the USA, reducing the risk of hefty fines and legal and reputational repercussions.
• Platform-specific risks: Android and iOS have inherent security strengths and weaknesses. With correct targeting, a pentest can uncover platform-specific vulnerabilities that might otherwise be missed, ensuring a holistic security posture.
• Securing API Integration: Mobile apps often rely on API integrations to access data and functionality. Pentesting can identify vulnerabilities in API authentication, authorization, and data validation processes, preventing unauthorized access to sensitive data through the API.

5 Parameters to Test During A Mobile Application Penetration Test

What are the Different Types of Mobile Apps That Organizations Use?

1. Native Mobile Apps

Designed for mobile devices, native mobile apps are usually created for a specific platform like Android or iOS. They use different programming languages, such as Java, Kotlin, Python, Swift, Objective-C, C++, and React.

They have full access to a device’s features, making them ideal for tasks like mobile banking with secure transactions or high-performance gaming with rich graphics. Industries like finance and gaming heavily rely on native apps to deliver exceptional user experiences.

2. Hybrid Apps

Hybrid mobile apps are a relatively new concept for mobile development. They offer a midpoint between native app functionality and broader reach. Built using web technologies such as HTML5, CSS3, and JavaScript, they run within a native app container, allowing them to function across platforms.

Hybrid apps are a good choice for industries like education, where you might need a mix of interactive content and offline functionality, or for enterprise use cases where internal business apps require data visualization, communication, and task management features.

Pro Tip: Develop cross-platform applications with Google’s Flutter UI. With a single codebase, you can build apps for Android, iOS, Linux, Mac, Windows, Google Fuchsia, and even the web.

3. Progressive Web Apps (PWA)

Think of PWAs as websites that act like apps and can be opened on any browser. They offer a lightweight alternative to native apps, with features like push notifications and the ability to work offline. 

This makes them ideal for situations where users need quick access to information or features without the hassle of downloading an app. E-commerce stores travel, and hospitality apps can benefit from PWAs, allowing for quick browsing without requiring extensive device resources. 

PWA apps also function as mobile apps and can be added to the home screen to be accessed like a native app.

Methodology of Mobile App Penetration Testing

Mobile application penetration testing is done in 4 steps mentioned below:

Step 1. Preparation and Discovery

Information gathering is a necessary step used in the penetration testing process. The techniques that are used in this phase are:

Mobile Application Static Analysis (SAST)

During mobile app pen testing, we leverage Static Application Security Testing (SAST) tools whenever possible to augment our analysis of the app’s source code.  These tools excel at pinpointing vulnerabilities that manual code review might miss, such as insecure coding practices or hardcoded credentials embedded within the app.

Some of the popular SAST tools in our arsenal include:

• AndroBugs: A powerful tool specifically designed to analyze Android applications.
• Static Analysis Framework (SAF): SAF is often built directly into mobile pen testing platforms and provides a robust code scanning capability.
• Checkmarx Mobile: A comprehensive SAST solution that delivers an in-depth analysis of mobile apps.

Open-Source Intelligence (OSINT)

Before diving into the pentest, we gather publically available information about the app, its creators, and the infrastructure supporting it.  Social media discussions, developer forums, and even app store listings can be valuable intel sources. Often, Open-Source Intelligence (OSINT) can reveal important information like:

• Upcoming features or functionalities mentioned in developer roadmaps that might be more vulnerable
• Usage trends and common user complaints that might indicate underlying security weaknesses.
• Technologies used in the app’s backend can help tailor exploitation attempts.

Mobile Network Traffic Analysis

Examining network traffic generated by the app helps us identify data transfer protocols (HTTPS vs. HTTP), endpoints being communicated with, and potentially sensitive data transmission. Tools like Wireshark and Burp Suite have usually proven invaluable in this phase.

Step 2. Analysis, Assessment, and Evaluation

After the completion discovery phase, our pentesters begin the analysis & assessment phase in which the application is observed before and after installation into the device. Some joint assessment techniques include:

1. Continued Static and Dynamic Analysis

In this phase, we perform a more in-depth SAST of the app’s code to uncover vulnerabilities like SQL injection flaws, buffer overflows, and insecure data storage practices. 

For dynamic analysis, the app is run in a sandbox environment to simulate real-world usage scenarios. This helps identify vulnerabilities that manifest during runtime, such as insecure input validation and cross-site scripting (XSS) flaws. 

Commonly, tools like Drozer and Frida help uncover common vulnerabilities such as:

• Insecure Input Validation: Here, the app fails to properly sanitize user input, allowing attackers to inject malicious code or manipulate data.
• Inter-Component Communication (ICC) Vulnerabilities: The app’s communication with other components on the device or backend servers has flaws that can be exploited for unauthorized access or privilege escalation.
• Insecure Direct Object References: In this case, the app references objects directly without proper authorization checks, potentially allowing attackers to access or modify unauthorized data.

2. Architecture Analysis

Understanding the app’s overall architecture is crucial. This includes its backend components, data storage mechanisms, and authentication protocols. By mapping the app’s architecture, we identify potential weaknesses in the entire system. Common architecture-related vulnerabilities include:

• Misconfigured Security Policies: Improper security settings on the app’s backend server or cloud storage can expose sensitive data or functionalities.
• Weak Authentication and Authorization: Flawed authentication protocols or inadequate authorization checks that allow unauthorized users to access the app or user data.
• Insecure Data Storage: Sensitive data like user credentials or financial information being stored unencrypted or on insecure servers.

3. Reverse Engineering

Disassembling the app’s code to understand its internal workings and identify hidden functionalities or obfuscated logic that might harbor vulnerabilities. This process is similar to decompiling a program to understand its logic and functionality at a deeper level. 

• Identify Obfuscated Logic: Developers sometimes obfuscate code to make it harder to understand and reverse engineer. However, this obfuscation can also mask vulnerabilities. 
• Analyze Custom Frameworks: Some apps utilize custom frameworks or libraries. Reverse engineering allows pentesters to understand the inner workings of these frameworks and identify potential security flaws within their implementation that might be missed by traditional analysis methods.
• Tools and Techniques: Popular tools for mobile app reverse engineering include IDA Pro, Ghidra, and JADX (for Java apps). Techniques employed during this phase involve disassembling bytecode or machine code, analyzing control flow graphs, and identifying function calls and data structures.

4. File System Analysis

Mobile apps often store data locally on the device for functionalities like offline access or user preferences. Examining the app’s local storage for sensitive data that might be improperly secured or accessible by unauthorized applications.

• Identifying Data Remnants: Even if the app claims to delete data, traces or remnants of that data might linger on the device. These remnants could be exploited by attackers to recover sensitive information. Techniques like forensic analysis of the file system can help identify such remnants.
• Sandboxing Bypass Attempts: Some apps might utilize sandboxing mechanisms to restrict their access to the device’s file system. Pentesters attempt to bypass these sandboxes to see if they can access sensitive data stored outside the app’s designated storage area.

Pro Tip: ADB (Android Debug Bridge) is a CLI tool that can be used to analyze the file system. Similarly, iExplorer can be used to review the iOS file system.

5. Inter-Application Communication (IAC) Analysis

Investigating how the app interacts with other apps on the device, including data sharing mechanisms and potential vulnerabilities that could be exploited to gain access to other apps’ data or functionalities.

• Insecure IPC Mechanisms: Apps might communicate with each other using various mechanisms, such as inter-process communication (IPC) or shared preferences. Pentesters analyze these mechanisms to identify weaknesses, such as a lack of proper authentication or authorization, improper data validation, and intent spoofing.
• Permissions Abuse: Apps often require specific permissions to function. Pentesters examine how the app utilizes these permissions and identify potential scenarios where an app might abuse its permissions to access data or functionalities of other apps.

Step 3. Exploitation

Based on the vulnerabilities discovered earlier by our team, the exploitation phase simulates real-world attacks such as malicious payloads like shell/root exploits to understand how they will behave if and when an attack occurs. 

Such exploits include:

• Custom-crafted exploits: Tailored to the specific vulnerabilities discovered in the app.
• Publicly available exploit kits: Pre-built tools designed to exploit common mobile app vulnerabilities.

Step 4. Reporting and Rescanning

Once the exploitation phase is done, the team prepares a detailed report of the attacks performed. The report includes:

• A list of tested endpoints and methodology.
• Description of identified vulnerabilities and their severity levels (CVSS scores).
• Risk assessment based on the potential impact of each vulnerability.
• Proof-of-concept (POC) exploits to demonstrate the vulnerability exploitation process.
• Remediation steps for developers to fix the vulnerabilities.
• A publicly verifiable pentest certificate (optional).

Rescanning: Ideally, beyond the pentest, you should also consider setting up periodic rescans after patching the identified vulnerabilities. This helps ensure the efficacy of the remediation efforts and helps identify and fix any potential lingering issues.

Top 5 Mobile App Vulnerabilities

1. Insecure Data Storage

This vulnerability occurs when sensitive user data, like login credentials or financial information, is stored on the device or transmitted in an unencrypted format. Hackers try to intercept data transmissions or gain unauthorized access to the device to steal this sensitive information.

In 2018, the popular fitness app Strava suffered a data breach due to insecure data storage. Hackers accessed the GPS data of millions of users, including military personnel, revealing their locations and routines.

Impact

Manipulating data, impersonating individuals, and committing identity theft. Insecure data storage also violates privacy laws and can result in hefty fines, legal issues, and revenue loss.

Prevention

Ensure proper data encryption using encryption keys, TLS, data encryption at rest, and secure storage mechanisms. Avoid storing data on devices.

2. Insecure Authentication

Weak authentication processes, such as relying solely on passwords or easily guessable PINs, make it easier for attackers to gain unauthorized access to user accounts. 

In June 2021, LinkedIn experienced a data leak when a hacker exploited a public API without authentication to scrape personal data on over 700 million users, including names, email addresses, and professional details. This puts users at risk of identity theft, phishing attacks, and impersonation. 

Impact

Unauthorized access to user accounts, potential for identity theft, financial loss, and compromise of sensitive data.

Prevention

Implement strong authentication methods (multi-factor authentication, biometrics), regularly update login credentials, and securely validate all user inputs.

3. Insufficient Input Validation

This vulnerability arises when the app fails to properly validate user input before processing it. Malicious actors exploit this by injecting code (SQL injection, Cross-Site Scripting) into the app’s input fields, potentially taking control of the app’s functionality, stealing user data, or redirecting users to phishing websites.

In 2016, Uber’s ride-hailing app experienced a security breach. Hackers exploited an SMS spoofing vulnerability to gain access to 57 million people’s user data. The attackers sent SMS messages containing malicious code that, when clicked, bypassed Uber’s login system and granted them unauthorized access.

Impact

Access the mobile app backend, manipulate app functionality, and access sensitive information.

Prevention

Ensure proper input validation measures are in place and enable output encoding to prevent injection attacks. Follow the best secure coding practices and use frameworks that offer built-in security against vulnerabilities.

4. Insecure Communication

If a mobile application is not developed carefully, it can expose backend systems to hackers. When data is transmitted between the app and the backend server without proper encryption (HTTPS), it becomes vulnerable to interception by attackers, who can then steal sensitive information like credit card details or personal data.

In 2014, a data breach exposed the private photos and messages of millions of Snapchat users. The attackers exploited the app’s insecure communication channels to intercept data transmissions between users and Snapchat servers.

Impact

Inadequate communications security exposes data to attackers’ interception, leading to eavesdropping, data theft, and man-in-the-middle attacks.

Prevention

Use secure data transmission protocols like HTTPS with strong encryption and a secure socket layer (SSL/TLS). Avoid insecure communication methods like HTTP or change to HTTPS, which offers more security.

5. Code Obfuscation

Code obfuscation is the process of transforming the source code of a software application to hinder attempts at reverse engineering or decompilation. Attackers use reverse engineering to understand how an app works to formulate exploits.

In a major 2019 data breach, a former Amazon Web Services engineer exploited misconfigured Capital One firewalls to steal Social Security numbers, bank account details, and credit information for over 100 million US and 6 million Canadian customers. This security lapse led to Capital One’s fines and criminal charges against the attacker, who used a server-side request forgery attack to access the data.

Impact

Code obfuscation, often a protective measure, can hinder security analysis if not implemented correctly, making it easier for attackers to reverse engineer the application to gain access.

Prevention

Additional security measures such as application hardening and runtime application self-protection (RASP) should be used to avoid reverse engineering attempts. Constantly update and patch the mobile app without fail.

Difference Between Static and Dynamic Analysis

S No.	Feature	Static Analysis	Dynamic Analysis
1	Execution	Does not require the execution of the mobile application	Requires execution of the mobile application on a device
2	Analysis Target	Decompiled source code, provided files	Local filesystem, inter-app communication, server communication
3	Testing Focus	Code quality, debug & error messages, business logic issues	Network communication, forensics, weak cryptography, user interactions
4	False Positives	Higher likelihood of false positives due to code assumptions	Lower likelihood of false positives, but may miss logic-based flaws
5	Visibility	Limited visibility into the runtime behavior of the app	Provides insights into real-world application behavior

How Can Astra Help?

Our comprehensive mobile app security services leverage a combination of SAST, DAST, and manual pentesting to achieve a 360-degree view of your app’s security posture. Simply upload your app, and our team takes the reins. 

Designed per industrial compliance standards and best practices, we subject your application to a rigorous battery of tests to uncover new and emerging vulnerabilities. Our CXO-friendly dashboard helps you create clear communication channels to ensure seamless collaboration between your team and our security experts. 

Astra vs. Open-Source Mobile Application Penetration Testing Tools

Feature	Astra Security	MobSF	Frida	Clutch (iOS only)
Testing Type	Multi-layered (SAST, DAST, Manual)	Static & Dynamic	Dynamic	Static (iOS)
Supported Platforms	Android & iOS	Android	Multi-platform	iOS
Ease of Use	User-friendly Dashboard	Scripting Required	Scripting Required	Moderate
Remediation Assistance	Actionable Steps	Limited	No	No
Compliance Support	Industry Standards	Not Supported	Not Supported	No

Final Thoughts

Mobile app penetration testing is crucial in safeguarding your app from potential vulnerabilities that cybercriminals can exploit. You can prioritize security measures during development by understanding the various vulnerabilities mobile apps are susceptible to, such as insecure data storage, insufficient input validation, and insecure communication.

Mobile app pentesting proactively identifies these weaknesses in your app’s code, architecture, and data storage before they can be used in a real attack. This helps protect user data, maintain user trust, and ensure compliance with data security regulations. By employing pentesting and understanding the different types of mobile apps and their vulnerabilities, you can ensure your app is secure and trusted by your customers.

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