How to secure mobile banking applications: Best practices

Mobile banking apps have become essential for financial institutions to stay competitive. However, as their popularity grows, so does the risk of cyberattacks. Strong security measures are crucial to protect user data and maintain trust. By prioritizing security, banks can ensure the safety of their customers' financial information while providing a convenient and efficient mobile banking experience.

By

• Monique Becenti
• Published: November 20, 2024

Mobile banking app security is as critical as the reputation of your bank. Financial institutions that prioritize security across their entire business can successfully balance convenience, agility, and regulatory requirements, all while ensuring their apps are resilient against advanced persistent threats.

Why is this so important? Mobile banking has rapidly evolved from a “nice-to-have” to a “can’t-live-without” service because of the convenience it offers. Without mobile banking apps, financial institutions will get left behind in the market.

According to recent research:

• 85% of leaders in the financial segment agree that using mobile-based services are essential for staying innovative and relevant to consumers.
• 70% say these services increase their agility and responsiveness.
• But agility isn’t enough—68% believe maintaining a strong cybersecurity reputation is critical to retaining customers, and 66% say it helps attract new ones.

Security isn’t just a technical challenge–it’s a competitive advantage. Let’s explore what mobile banking application security entails, why it matters, and how to effectively implement security throughout the lifecycle of the application.

What is mobile banking application security?

Mobile banking application security involves protecting these apps from cyber threats, unauthorized access, and data breaches during the software development lifecycle (SDLC) and beyond.

Security starts during development, with a focus on ensuring the app’s code is free of vulnerabilities and privacy issues before publishing to the app stores. This means using secure coding practices, thorough testing, and threat assessments at every step of the development process. Starting with a solid foundation and understanding of mobile app security can help reduce risks by spotting and fixing weaknesses before apps are downloaded by customers.

Once a mobile banking app is deployed, additional security layers become critical to safeguard user data. Multi-factor authentication (MFA) plays a pivotal role in “trusting before verifying” passwords combined with biometrics or SMS authentication before providing access to the user’s banking information. Regular updates, patches, and continuous monitoring ensure the app remains secure as threats evolve.

Encryption further protects sensitive data by securing it both in transit and at rest, ensuring it remains unreadable to anyone without proper decryption keys. Combined with regular updates, patches, and continuous monitoring, these measures are ways to incorporate security measures into the development of a banking app.

Why is mobile banking app security important?

With users checking their mobile banking apps more frequently than websites, these apps have become the primary touch point between financial institutions and their customers. This increased reliance makes them a prime target for attackers and a critical risk point for businesses.

Mobile apps are now the center of fraud schemes, as cybercriminals exploit vulnerabilities to access sensitive data, manipulate transactions, and deceive users.

Without strong security, a compromise could lead to:

• Identity Theft: Bad actors can steal sensitive personal information, such as Social Security numbers and login credentials, which can then be sold on the dark web or used to commit fraud.
• Unauthorized Access: Criminals gaining entry to user accounts can lead to stolen funds, altered account settings, or fraudulent transactions in a matter of minutes.
• Fraudulent Transactions: Attackers initiating unauthorized payments, redirecting legitimate ones, and manipulating account activity.
• Financial Losses and liability: Customers can lose their savings to scams or phishing attacks, and banks may face an average of $6.08 million in costs associated with a data breach. Banks are often required to reimburse customers for losses incurred from fraud, resulting in more cost.
• Reputational Damage: A single breach can damage years of trust, making customers hesitant to use mobile services or even prompting them to switch to competitors.

Why do cybercriminals target mobile banking apps?

Mobile banking apps hold a wealth of sensitive information, making them highly attractive to nefarious cybercrime. Beyond direct attacks, one tactic is the creation of fraudulent copies of legitimate banking apps designed to deceive users.

These counterfeit apps, often distributed through unofficial app stores or malicious links, mimic the look and functionality of real banking apps. Once users download and log in, attackers can harvest sensitive data such as:

• Login Credentials: Usernames, passwords, and multi-factor authentication tokens that provide access to financial accounts. A single compromised account can lead to unauthorized transactions or deeper infiltration into a user’s financial ecosystem.
• Personal Identifiable Information (PII): Data like Social Security numbers, addresses, and phone numbers, which can be used for identity theft or sold on the dark web. This data has lasting value, enabling attackers to create long-term fraud schemes.
• Financial Data: Bank account numbers, transaction history, and credit card information are directly exploitable for theft, fraudulent purchases, or account takeovers.

The exploitation of fake banking apps

For cybercriminals, compromising a mobile banking app isn’t just a one-time win—it can open the door to ongoing opportunities for exploitation:

• Steal Money Directly: Fraudulent apps can redirect users’ payments to the attackers’ accounts or initiate unauthorized transactions without the user’s knowledge.
• Harvest Data for Identity Theft: The stolen data can be used to create false identities, open new accounts, or apply for loans in the victim’s name.
• Distribute Malware: These apps often include malware that infects devices, allowing attackers to monitor user activity, steal additional credentials, or gain access to other sensitive apps.
• Erode Trust in Legitimate Apps: When users fall victim to these scams, they often lose trust in mobile banking entirely, impacting the reputation of legitimate financial institutions.

Threats and risks to mobile banking apps

Cybercriminals continually evolve their tactics to target banking apps, focusing on efficiency and effectiveness. While the total number of banking trojan attacks has remained steady compared to 2022, there’s been a slight drop in unique installation packages. This indicates that attackers are reusing and refining existing malware, using proven methods to target new victims. These optimized strategies make attacks more efficient, harder to detect, and increasingly difficult to defend against.

Even with stable malware volumes, the persistence and sophistication of these attacks continue to pose significant risks to mobile banking apps. To safeguard your app and its users, it’s critical to understand the most common threats:

• Malware and Banking Trojans: These malicious programs infiltrate devices, silently stealing credentials and financial data.
• Fake Banking Apps: Fraudulent apps mimic legitimate ones, tricking users into sharing login details.
• Man-in-the-Middle (MITM) Attacks: Hackers intercept communication on public Wi-Fi networks, stealing sensitive data as it’s transmitted.
• Phishing Scams: Deceptive text messages or emails lure users into revealing private information.
• Colluding Apps: As highlighted by Quokka, colluding apps are apps that silently cooperate to share sensitive information, often exploiting insecure APIs or poorly configured permissions. These apps are a growing threat to user privacy.
• Clickjacking and Keylogging: Attackers exploit hidden links or use software to record keystrokes, exposing critical credentials.

Regulations and standards for mobile banking app security

Financial institutions must adhere to stringent regulations to protect customer data and maintain compliance. Some key standards include:

• PSD2 (Payment Services Directive 2): Requires strong customer authentication (SCA) for online payments to prevent unauthorized transactions and reduce fraud across the European Union.
• FFIEC Cybersecurity Guidelines: Provides a framework for assessing and improving cybersecurity for U.S. financial institutions, helping them address emerging threats and vulnerabilities.
• PCI DSS (Payment Card Industry Data Security Standard): Governs the secure handling, storage, and transmission of payment card data, minimizing the risk of breaches and ensuring consumer confidence in digital payments.
• GDPR (General Data Protection Regulation): Sets strict standards for protecting EU user data, including consent requirements and the “right to be forgotten,” with severe penalties for non-compliance.

These frameworks serve as essential guardrails for financial institutions, helping them protect sensitive customer data, maintain trust, and avoid the steep financial and reputational costs of a security breach.

How to develop secure mobile banking apps

Developing a secure mobile banking app requires a comprehensive approach that considers advanced persistent threats and vulnerabilities at every stage of the software development lifecycle (SDLC). Security isn’t a feature to tack on—it must be a fundamental design principle.

Start with a Security by Design Mindset

By adopting a security-by-design mindset, developers can work cross-functionally with their security team to identify potential attack vectors during the planning stage, using secure coding practices during development, and conducting rigorous testing before deployment.

Perform Mobile App Security Testing

Testing is critical to uncover hidden vulnerabilities and ensure the app remains secure. Employ a layered testing approach, including:

• Static Application Security Testing (SAST): Analyze source code early in development to identify vulnerabilities before they become embedded in the app. This proactive approach allows developers to fix issues at the source, reducing downstream costs and risks.
• Dynamic Application Security Testing (DAST): Evaluate the app during runtime to uncover vulnerabilities that only appear in real-world conditions, such as during specific user interactions or external communications.
• Interactive Application Security Testing (IAST): Monitor the app in real time during testing, combining the strengths of SAST and DAST. IAST provides deeper insights into how vulnerabilities manifest during operation, enabling more precise remediation.

To streamline these efforts, developers and security teams can integrate these testing tools into their CI/CD (Continuous Integration/Continuous Deployment) pipelines. This ensures continuous, automated security checks as new code is written and deployed, catching vulnerabilities early and maintaining the app’s security posture as it evolves.

Secure Third-Party Libraries & APIs

Most mobile apps depend on third-party libraries and APIs to deliver essential functionality and improve user experience. However, these external components can also introduce significant vulnerabilities if not managed properly. Insecure, outdated, or unverified third-party elements can act as weak links, providing attackers with entry points into an app.

To mitigate supply chain risks:

• Verify the Source and Security of Libraries: Only use libraries from reputable sources and validate their integrity before integrating them into your app. Ensure they are free from known vulnerabilities or malicious code.
• Use Trusted, Up-to-Date Components: Regularly update third-party libraries to the latest versions, as updates often include critical security patches that address newly discovered vulnerabilities.
• Conduct Regular API Audits: Assess all APIs the app interacts with to identify potential weaknesses. Ensure APIs are encrypted to protect data in transit and authenticated to prevent unauthorized access.
• Maintain a Software Bill of Materials (SBOM): Create and maintain an inventory of all third-party libraries, APIs, and dependencies in your app. An SBOM allows you to track components, quickly identify vulnerabilities, and effectively respond to supply chain threats.

Third-party integrations are crucial to modern app development, but they require careful oversight due to potential security concerns.

Adopt End-to-End Encryption

Encryption protects sensitive data by converting it into unreadable formats that can only be decrypted by authorized parties. Implement end-to-end encryption to secure data at all points:

• In transit: Encrypt data as it moves between the user’s device and your servers. This minimizes the risk of interception by attackers during transmission, such as man-in-the-middle (MITM) attacks on public Wi-Fi networks.
• At rest: Encrypt stored data to safeguard it against unauthorized access in the event of a breach or device compromise. This ensures sensitive information remains protected even if physical devices or databases are accessed by malicious actors.

Robust encryption ensures that even if attackers intercept data, they won’t be able to decipher it.

Mobile banking app security best practices

Securing a mobile banking app starts with proactive measures to identify and address vulnerabilities before they can be exploited. Let’s take what we have learned and prioritize them to create a list of best practices.

What to prioritize?

• Conduct Regular Security Testing: Perform comprehensive tests to uncover vulnerabilities at every stage of development. This includes static, dynamic, and interactive testing to ensure your app can withstand real-world attacks.
• Build Security into the Development Process: Use secure coding practices and integrate testing into your CI/CD pipelines to catch and resolve issues early.
• Strengthen Authentication: Implement multi-factor authentication (MFA) and biometrics like fingerprint or facial recognition to prevent unauthorized access.
• Encrypt Data Everywhere: Use end-to-end encryption for data in transit and at rest, ensuring sensitive information stays secure even if intercepted.
• Monitor and Patch Continuously: Regular updates and patches help address emerging threats and vulnerabilities, keeping your app resilient over time.
• Secure APIs and Third-Party Libraries: Authenticate and encrypt API communications, and vet external components to reduce risks from external integrations.
• Prioritize Compliance: Align with industry regulations such as PCI DSS, PSD2, and GDPR to protect user data, avoid penalties, and build trust with customers.

The security of mobile banking apps is absolutely non-negotiable. By integrating these practices into your app’s lifecycle, you not only reduce the risk of breaches but also deliver a secure, reliable experience that users trust. With cyber threats becoming increasingly sophisticated, banks must continually update and enhance their security protocols to protect their customers’ data and assets.

How can Quokka help

Building a mobile banking app isn’t just about delivering features—it’s about creating something users can trust. The challenge goes beyond functionality. Tight deadlines, complex codebases, and an evolving threat landscape make embedding security a daunting task. Securing mobile apps doesn’t have to be complicated; the solution needs to provide you the right insights to remediate issues within your code faster and more efficiently.

Quokka Q-mast: Security Built for Mobile App Development

Quokka’s Q-mast embeds security directly into the development process, running in-depth testing at every stage. It uncovers risks and provides actionable insights to fix vulnerabilities early, ensuring your app is secure from start to finish. Security doesn’t have to be an obstacle. With Quokka, it’s an integral part of delivering reliable, trusted applications to your users.