In May 2024, Microsoft discovered a vulnerability pattern in Android apps, which allowed overwriting files in the app’s home directory. What’s worse, several of the affected applications had over four billion installations.
According to the OWASP Mobile Application Security, vulnerabilities like file overwrite issues fall under common mobile app threats (e.g., insecure data storage, insufficient cryptography). Additionally, the Android Security & Privacy Year in Review published by Google highlights various real-world exploit scenarios and patch timelines, emphasizing the importance of addressing these risks promptly.
Meanwhile, research shows that 74% of consumers would abandon brands that experienced a breach, encouraging their friends to follow. 94.6% of people are willing to promote security-conscious brands.
This reminds us of two important things:
- Even popular, tried-and-true systems are not immune to security problems.
- Digital safety is of critical importance for users.
Hence, securing your Android application is non-negotiable. In this guideline, we’ll share the basic guidelines on how to build safe and reliable apps for Android users.
What is Android App Security?
Android app security refers to the set of practices and technologies used to protect applications and their users from threats. The latter can include unauthorized access, data breaches, malware infections, and various malicious attacks.
Adequate Android application security isn’t just about writing secure code. It also relies on exploiting Android’s built-in security features, such as app sandboxing and runtime permissions. In addition, Android app security involves multiple layers of protection, including strong authentication mechanisms, data encryption, access controls, and more.
Through Android mobile application security, businesses can ensure that their solutions handle user data safely and resist exploitation by attackers.
Importance of Secured Android Apps
Securing Android apps is critical from both technical and business viewpoints. Adopting recognized guidelines such as the OWASP Mobile Application Security Verification Standard (MASVS) and OWASP Mobile Security Testing Guide (MSTG) ensures that your application meets a baseline of security controls expected in the industry. Following these standards helps organizations align technical requirements with compliance mandates and user trust, bridging the gap between security theory and practical implementation. Safe-to-use applications enable the following:
- Protecting user data. The software handles sensitive information—personal details, login credentials, and payment data, among others. Improper security can lead to privacy violations, identity theft, and financial loss.
- Preventing malicious activities. Vulnerable apps serve as entry points for attackers, who can compromise devices, steal data or money, or spread malware.
- Preventing financial loss. Unsecure apps can result in financial losses for both users and businesses. A great deal of fraudulent activities target businesses for financial gains.
- Complying with regulations. Regional data protection laws (like GDPR and CCPA) mandate specific security measures. Failure to comply can result in legal consequences, fines, and a total ban of an app.
- Maintaining user trust. Users expect their data and devices to remain secure. A security flaw always affects a brand’s reputation. After serious incidents, it can damage it, leading to user attrition.
Securing Android applications is clearly a technical necessity. However, it is also a business and ethical imperative. The cost of a data breach jumped to USD 4.88 million — by 10% since 2023. That’s the highest increase since the pandemic. Operational downtime lost customers, and the cost of post-breach responses is high. This reminder alone can be motivating enough to invest in Android app security.
Android App Security Features
Android provides advanced built-in security features. Although the extra setup is still required, you already have solid mechanisms to reduce the risk of mobile vulnerabilities. The key Android application security mechanisms include:
- Security at the OS level. Each Android device is built on the Linux kernel, providing a solid security foundation. The kernel ensures basic protection through features like process isolation, user-based permissions, and memory management.
- Application sandboxing. Each app runs in its isolated environment—a mandatory application sandbox. It cannot directly access data or resources from other apps. This limits the impact of any potential security breach on the affected app alone.
- Application signing. Developers are required to sign their apps with a cryptographic key— a unique identifier for the app. It also allows verify updates, ensuring they come from the same developer and haven’t been tampered with.
- Secure storage. Android’s Keystore system allows apps to securely store and manage cryptographic keys. The sensitive data is encrypted with those keys that cannot be easily extracted. Penetration testers often validate the Keystore’s correct usage by attempting to extract or misuse keys through reverse engineering and dynamic instrumentation tools. Correct integration of the Keystore, combined with hardware-backed security components, can significantly raise the bar against adversaries trying to exfiltrate cryptographic material.
- Permissions system. Android uses a runtime permission model. Users can grant or deny app access to sensitive resources (location, camera, contacts, etc.). Apps must explicitly declare the required permissions during installation.
- Secure interprocess communication (IPC). When apps need to communicate with each other, Android uses secure IPC mechanisms. These ensure that only authorized apps can exchange data.
- Network security configurations. Android supports secure network protocols like HTTPS and SSL/TLS certificates to encrypt data transmitted over networks.
- Google Play Protect. Google has a security service that scans apps in the Google Play Store and on devices for malware or suspicious behavior. It regularly checks installed apps to identify potential risks. Moreover, security professionals conduct regular security assessments that test the resilience of these protective measures. For example, penetration testers will emulate malicious apps and attempt to bypass Google Play Protect safeguards, ensuring that your security posture isn’t solely dependent on platform defaults.
As you can see, Google facilitates Android application protection for mobile app developers. You get to work with a responsible and helpful platform instead of configuring everything from scratch.
Understanding Android Application Security
Android uses multiple layers of security, covering code, data, network, and user authentication and authorization. A few words about how it works in practice.
Let’s take sandboxing. For example, a messaging app cannot access your contacts unless you explicitly grant them permission. On the other hand, a weather app without permission to access your photos will remain restricted to its mandatory application sandbox, ensuring it can’t view or modify your image gallery.
Or let’s take a look at Google Play Protect. It scans apps during installation and while on your mobile device, checking for malicious software or suspicious behavior. For example, if you install a flashlight app that requests access to your text messages or location, Google Play Protect will issue a warning.
The Android application security system may seem all-embracing and self-sufficient. How’s it so that you need to add custom levels of protection on top of it all? It’s impossible to set defenses for all threats, especially when they evolve quickly.
Under the hood, Android enforces Security-Enhanced Linux (SELinux) policies to enforce mandatory access control. While SELinux provides a robust baseline, penetration testers explore configurations to identify misconfigurations that allow privilege escalation. Additionally, features like Play Integrity API help detect tampered environments and untrusted devices. A skilled security team will simulate such tampering attempts to ensure your app appropriately reacts to compromised environments.
Cyberattacks might also exploit previously unknown flaws (zero-day vulnerabilities). Malicious actors can trick users into revealing data through phishing emails or fake apps. To counter these risks, tech teams should look into scenarios that allow for bypassing default security.
Main Security Issues Associated With Android Apps
Android applications face several common security challenges that can put user data, privacy, and device functionality at risk. Being aware of these issues is the first step to mitigating them. Start by preparing counter strategies for the following threats.
Phishing Attacks
Malicious actors can attempt to make software users reveal their login credentials or payment details. It often happens via fake login pages disguised as legitimate apps or malicious links in emails, messages, or in-app ads.
Data Leakage
Android apps may inadvertently expose sensitive user data. It usually happens due to insecure storage practices, improper encryption, misconfigured cloud services, or APIs that expose user information.
Malware Infections
Malware can infect devices, leading to data theft, unauthorized actions, or device compromise. Google Play Protect reduces these risks, but it’s still easy for Android device users to download apps from unofficial sources. This is what makes an app vulnerable.
Excessive Permissions
Sometimes, apps request permissions beyond what is necessary for their functionality. While some only aim to gather more data for personalization, this often creates opportunities for misuse, especially if the app is compromised.
Weak Authentication
Apps with simple passwords or no multi-factor application authentication are easy targets for credential-stuffing or brute-force attacks. Meanwhile, weak authorization setups can open access to devices or normally restricted actions.
Insecure Networks
Apps transmitting data via unencrypted connections leave users exposed users to man-in-the-middle attacks. Hackers can intercept and manipulate data exchanged between the application and its server.
Outdated Libraries
Many Android apps rely on third-party libraries. Some may contain vulnerabilities. If not updated promptly after revealing the weakness, attackers can exploit them to access sensitive data.
For instance, vulnerabilities like CVE-2021-42574 demonstrated how certain Unicode handling in libraries could be exploited. Penetration testers commonly use scanning tools to identify such vulnerabilities early, ensuring that outdated libraries are flagged and updated before malicious actors exploit them.
App Impersonation
Malicious actors may create fake apps that mimic widely-used real ones to steal user data, install malware, scam users, etc. These fraudulent apps may be flagged in Google Play. Still, they may circulate freely outside the official platform.
Side-Channel Attacks
Attackers exploit indirect information leaks instead of code or data. It’s often related to device hardware. Hackers might analyze power consumption, electromagnetic emissions, or even execution time to infer sensitive information.
Android Application Security Checklist
Ideally, ensuring security requires attention to detail at all phases, from planning to maintenance. An Android security checklist should account for the common issues mentioned above. It should also consider the particularities of your industry and your specific solution.
It would be impossible to provide an extensive one-fits-all checklist with universal application security assessment steps. The list below will be a good start for developing your security strategy.
Secure Coding
Follow secure coding practices from the very start. Don’t hardcode sensitive information like API keys. Validate all inputs. Sanitize outputs to prevent common attacks like injection or buffer overflows.
For instance, adhere to OWASP MASVS requirements for secure data handling. This ensures data-in-transit integrity, making man-in-the-middle attacks far more difficult. A penetration tester would attempt to intercept traffic with tools like Burp Suite and verify if the pinned certificate rejects unauthorized proxies.
Data Encryption
Encrypt all sensitive information. It goes for both data in transit and at rest. Use strong encryption standards, for example, AES-256 for storage and TLS for communication. They will keep data coded and secure even in case of interception or leakage.
Secure Storage
Avoid storing sensitive data in plain text or in easily accessible locations. Don’t use cloud or digital storage for important and private information. Instead, opt for Android’s Keystore system or an alternative.
Secure Network Traffic
Make sure to prevent data interception and manipulation. Configuring HTTPS by default for all app communications is the first step. Also, validate server certificates and implement secure communication protocols. Ensure API security, protecting them with proper authentication, encryption, and input validation.
Strong Authentication and Authorization
Implement strong application authentication mechanisms, like OAuth and multi-factor authentication. Set up accesses for users and processes to reduce the risk of privilege escalation. Make sure it’s only possible to access the resources a user or function is authorized to access.
Restricted App Permissions
Limit the permission for your app. Leave only what’s necessary for the functionality. Request sensitive permissions, such as location or camera access, only when absolutely necessary. Use runtime permissions for better user control.
Hardened Access Controls
Control access to app components, APIs, and data. Make sure to secure the app on the backend. For instance, you can implement rate limiting and strong session management to prevent abuse.
Secure Third-Party Dependencies
Track the state of third-party libraries and other dependencies your app uses. It’s critical to update and validate them regularly. Monitor for known vulnerabilities and avoid outdated components that may expose your app to risk.
Timely Patching
Stay informed about relevant updates by Android and the rest of the tech stack you use. Apply patches for vulnerabilities as soon as they are released.
Full Compliance
Follow platform-specific guidelines established by Google Play. Ensure compliance with local regulations. Check for the industry-specific standards in your business domain.
Regular Code Audits
Perform thorough code reviews on a regular basis. It will help identify existing or emerging vulnerabilities and improve overall security practices. You combine manual checks with automated tools for better efficiency.
Application Security Posture Management
ASPM means continuous monitoring, assessment, and improvement of the security of applications throughout their lifecycle. It promotes identifying vulnerabilities, misconfigurations, and security gaps in applications during development, deployment, and runtime.
Company Policies and Practices
Establish the requirements and policies for the secure software development process. Educate your team. Ensure that everyone knows the importance of data security from both technical and business viewpoints. Conduct regular lessons and training sessions to prevent common mistakes.
Android App Security with Iterasec
The insights and practices shared above are based on our extensive experience with a wide range of applications running on Android. Iterasec is a team of over 20 experts specializing in cybersecurity services, ranging from penetration testing to compliance audits.
We have experience working with companies of different sizes and from different domains. We apply a structured penetration testing methodology aligned with the OWASP MSTG, starting with reconnaissance and threat modeling, and moving through vulnerability analysis, exploitation, and post-test remediation guidance. This approach ensures that our clients receive a thorough assessment of their application’s security posture.
By integrating penetration testing into your Secure Development Lifecycle (SDLC), we ensure vulnerabilities are identified and remediated early. We also provide training workshops and secure coding sessions for your developers, bridging the gap between security requirements and practical implementation. This proactive engagement reduces long-term risks and aligns your business with industry standards and compliance mandates.
Whether you are about to launch a new app or aim to enhance a long-existing product, our team can assist with ensuring Android application security. Contact us to learn more and discuss the details.
Conclusion
Securing Android apps requires ongoing commitment. A single application vulnerability could compromise sensitive data, wreck user trust, and affect a brand’s reputation beyond repair. Meanwhile, attackers are becoming more sophisticated in their efforts to create and exploit these vulnerabilities.
It would be correct to say that Android security best practices are a mindset rather than a technical guideline with all application security acronyms explained. Incorporating continuous penetration testing, threat modeling exercises, and automated security checks into your CI/CD pipeline ensures that security is not a one-off event, but an ongoing process. By building on top of Android’s built-in protections with industry standards (MASVS), hardened configurations, and professional security assessments, organizations can outpace emerging threats and maintain a robust security posture.
