Mobile app security: risks, protection, and best practices

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Today we live glued to our phones and their apps, but we rarely stop to think about the risks we take every time we install an app or connect to a public Wi-Fi network . From the theft of personal data to large-scale malware attacks, the threats continue to grow at the same rate as the number of smartphones in circulation.

If you use your phone for work, managing your money , or simply chatting and uploading photos, you'll want to know how to protect your device, what built-in security systems like Google Play Protect do, and what best practices you and developers should follow . Let's take a look at it calmly, but without beating around the bush.

Why is security so important in mobile apps?

Mobile security encompasses all measures designed to protect your smartphone or tablet from problems such as data breaches, espionage, malware, ransomware, or scams. It's not just about installing antivirus software and forgetting about it, but about understanding that mobile phones now concentrate a large part of our digital lives : contacts, photos, credentials, banking apps, work, entertainment, and more.

In recent years, the number of smartphone users has skyrocketed, leading cybercriminals to focus on these devices. Cybersecurity companies have detected tens of millions of malware, adware, and riskware attacks on mobile devices in a single year , with significant year-over-year increases. In other words, mobile phones are no longer a secondary target; they are the primary target.

Furthermore, it's important to keep in mind that protecting a teenager's personal mobile phone is not the same as protecting the corporate device of someone handling sensitive company data . However, in both cases, the weak point is often the same: installing apps without checking them , using open Wi-Fi networks, weak passwords, and a false sense of security.

Main risks: what can be stolen or damaged with an insecure app

When we talk about mobile app security, we're not just thinking about classic viruses. A poorly designed or malicious app can lead to the theft of sensitive information, financial losses, and reputational damage for both users and companies.

One of the most common dangers is the theft of personal data and login credentials . This includes names, email addresses, phone numbers, passwords for platforms and social networks, and so on. With this data, thieves can impersonate others, open new accounts, or access other applications where you reuse passwords.

Another critical area is stolen financial data : credit cards, online banking access, mobile payment services, cryptocurrency wallets, and e-commerce apps. Many malware campaigns focus precisely on intercepting SMS codes, screens, or forms from financial apps to empty accounts or make fraudulent payments.

In the case of businesses and professionals, the theft of intellectual property also comes into play : source code, internal documents, designs, business strategies, or customer information stored or accessible from a mobile device. A well-executed attack against a corporate app can wipe out years of work in a matter of minutes.

We must not forget the reputational damage . A breach in an official app (for example, from a bank, insurance company, or messaging service) can erode the trust of thousands or millions of users. Often, the reputational impact and potential regulatory penalties for inadequate data protection are as serious as the attack itself.

5 reasons why threats against mobile apps keep growing

Attackers have learned to exploit the mobile ecosystem. Today, there are five major factors that contribute to the increase in attacks against applications installed on smartphones and tablets.

First, cybercriminals exploit the app distribution platforms themselves . Through supply chain attacks, they can compromise SDKs (software development kits) used by popular, legitimate applications. Thus, a single incident in a library used by several apps can end up infecting millions of devices without the user's knowledge.

A second factor is the insecure storage of data within applications. When sensitive information (tokens, API keys, personal data) is stored without adequate protection, it is much easier to extract it through reverse engineering, rooted devices, or malicious apps that exploit access to shared areas.

Vulnerabilities in communications also play a role . If an app doesn't properly encrypt traffic to the server or accepts insecure certificates, an attacker on the same network (for example, on public Wi-Fi) can intercept and manipulate data in transit, from credentials to banking information.

In addition to the above, there are deficient authentication procedures . Apps that continue to allow weak passwords, that do not apply locks after several failed attempts, or that do not take advantage of biometric systems and multi-factor authentication, make it easy for anyone with physical access to the mobile phone or with leaked credentials to gain entry without much difficulty.

Finally, many applications misuse data encryption . They employ outdated algorithms, mismanage cryptographic keys, or mix encrypted and unencrypted data in the same place, opening the door to both local and remote attacks against information confidentiality.

Google Play Protect: the first protection barrier on Android

On Android devices , Google integrates a system called Google Play Protect that acts as an automatic guardian for apps and the system itself. While it doesn't replace good user behavior or other security solutions, it provides a valuable layer of continuous protection.

This system analyzes apps available on Google Play before you download them, looking for suspicious or malicious behavior. This way, many dangerous apps are blocked before they even reach users' devices, reducing the risk at the source.

In addition, Google Play Protect regularly scans all the apps installed on your phone , including those from sources other than the official store. In its terminology, these potentially harmful applications are called malware and can be detected even if you installed them manually from an APK file.

When the system identifies an app as dangerous, it can act in several ways. It may display a warning encouraging you to uninstall it, disable it so it stops working until you remove it, or even delete it automatically . In most cases, you'll receive a notification explaining what happened and what measures were taken.

Google Play Protect also issues privacy alerts when it detects apps that hide relevant information or abuse user permissions, violating unwanted software policies or developer guidelines. On certain Android versions, it can even reset permissions granted to apps you rarely use to reduce unnecessary access to your data.

Finally, this system can prevent the installation of unverified apps that request particularly sensitive permissions often used for financial fraud , thus blocking many scam attempts before the damage materializes.

How to check and adjust Google Play Protect on your device

To get the most out of this layer of protection, it's a good idea to make sure everything is in order. First, you can check if your device is certified for Play Protect . Simply open the Google Play Store app, tap your profile icon in the upper right corner, go to the settings section, and look for the information section, where the certification status will be displayed.

Under normal circumstances, Google Play Protect is enabled by default , but it can be disabled manually. For security reasons, it's highly recommended to keep it on. To check or change this setting, go to the Google Play Store, tap on your profile, access Play Protect, and then its settings, where you can enable or disable app scanning.

When you install apps from outside the official store, the system may ask for permission to send copies of these unknown apps to Google . If you enable the option to improve malware detection, Play Protect will automatically send samples of these apps to Google's servers for in-depth code analysis.

Managing this feature also involves the Google Play Store and the Play Protect menu . In its settings, you'll find a switch to turn the enhanced detection option on or off. If you're a developer, you may be required to manually upload each new version of your app to facilitate this type of analysis and prevent false positives or security issues.

In Android versions 6.0 through 10, Play Protect also includes a mechanism to automatically reset the permissions of apps you haven't used for three months . You'll receive notifications when this happens, and you can access the Unused Apps permissions section directly from the Play Protect interface to see what permissions have been reset.

If you don't want a specific permission to be automatically revoked in a particular app, you can open the app list, select the one you're interested in, and disable the option to remove permissions when not in use . However, once Play Protect has revoked permissions, it won't automatically grant them again; it will simply stop affecting other permissions.

What does Google do with data related to malware?

To effectively detect threats, Google needs certain technical information from your device. Among other data, it may collect information about network connections, potentially dangerous URLs, and installed apps , whether they came from Google Play or other sources.

When an app or web link is deemed unsafe, you may receive a warning explaining that it could pose a risk to your device, your data, or your personal security . In more serious cases, Google may automatically remove the app or block installation and access to that URL if it is known to be harmful.

Play Protect often recommends scanning apps that aren't on Google Play and haven't been reviewed before. During this scan, technical details are sent to Google's servers, the code is evaluated, and after a short time, a result is displayed indicating whether the app appears safe or has been classified as potentially dangerous.

Some of these features can be disabled from the device settings if you want to limit data transmission, but even in that scenario Google may still receive some basic telemetry related to the apps you download from its own store to maintain the overall security of the ecosystem.

Device certification and the "Device is not certified" error

It's important to understand that Google Play Protect and device certification are different things . It's possible that everything appears correct in Play Protect, but you'll still see a warning that your device isn't certified for Google Play.

If you see the message “ Your device is not certified ,” trying to fix it by adjusting the Play Protect settings won't help. Instead, tap the button indicating a problem with your device and follow the on-screen instructions provided by Google to complete the device verification or registration process.

If you cannot find the option, you can open the Google Play app, tap your profile picture, go to settings, go to the information section, and scroll down to the Play Protect certification field , where you will find the status, the option to correct any errors, and additional documentation on the most common causes and solutions.

Most common types of mobile threats

Beyond configuration errors, the biggest threat to mobile security is the various malware families and social engineering techniques that try to infiltrate our devices. To defend yourself effectively, it's helpful to recognize the main categories.

One of the most common threats is adware , software that aggressively displays advertising and, in many cases, serves as a gateway for more serious threats. In some recent analyses, more than 40% of the threats detected on mobile devices fell into this category, which gives an idea of ​​its reach.

Data leaks through excessive app permissions are also a concern , especially in apps marketed as free. Some collect more information than necessary for commercial purposes or even to sell it to third parties. Changes to operating systems, such as the transparency in app tracking introduced in iOS , have attempted to curb this practice by requiring clearer consent.

Another widely exploited vector is public or poorly configured Wi-Fi networks . Because they are not encrypted or are weakly encrypted, they allow an attacker connected to the same network to intercept data in transit, manipulate traffic, or even set up fake access points that mimic legitimate networks to steal credentials and active sessions.

Classic phishing attacks have also adapted to the mobile world. Emails, SMS messages, or messages in messaging apps that impersonate banks, messaging services, or well-known platforms try to trick you into entering your login credentials on fake websites or downloading malicious attachments that will install malware on your device.

In the realm of covert espionage, we find spyware and stalkerware , tracking applications that can record your location, messages, or calls without your knowledge. This type of software has been detected on tens of thousands of devices in recent analyses, affecting both victims of abusive control and users targeted due to their professional position.

The general umbrella of mobile malware includes banking trojans, ransomware that encrypts your files and demands a ransom, tools that intercept verification codes, and those that steal files and credentials. The entry point is usually a suspicious link, an app downloaded from outside official app stores, or a malicious attachment opened without verification.

Finally, we must mention cyberterrorism and cyberespionage attacks targeting high-ranking officials, employees of large companies, or government employees . In these cases, personal or corporate mobile phones become gateways to critical networks and large volumes of strategic information.

Basic best practices for users: how to protect your mobile phone and your apps

Security technology helps, but your behavior makes all the difference. There are a number of best practices that every user should follow.

The first thing is to always keep your operating system updated . Each new version of Android or iOS includes security patches that fix discovered vulnerabilities. If you indefinitely postpone updates, you leave your device exposed to flaws that attackers already have exploits ready to exploit.

It's also highly recommended to disable remote connectivity when you don't need it : Bluetooth, AirDrop, Wi-Fi, or personal hotspots. In public spaces, the smaller your device's attack surface, the better. This reduces the chances of unauthorized connections or attempts to send malicious content.

When installing new apps, get into the habit of carefully reviewing the permissions they request . Ask yourself if a flashlight app really needs access to your contacts or if a game requires your location constantly. If you find an unfamiliar app that you don't remember installing, delete it immediately.

Another key tip is to download apps only from official stores like Google Play, the App Store, or recognized repositories in your region. Within these stores, pay attention to reviews, the number of downloads, the developer, and their other apps. Few reviews, all of them perfect, or a well-known name with very few installs are red flags.

To lock your device, take advantage of biometric access options : fingerprint or facial recognition . Combining these with a strong PIN or password makes it much harder for someone who steals or finds your phone to directly access your data and apps.

Finally, remember to enable two-factor authentication (2FA) on important services . Whenever possible, use authenticator apps instead of SMS, as they are less vulnerable to certain types of attacks. A password manager can help you create different and complex passwords for each service without having to memorize them all.

Applications that help improve security and privacy

In addition to the operating system's built-in features, there are many apps specifically designed to enhance the security and privacy of your mobile device. It's helpful to know the main types and what they offer.

Mobile antivirus, antimalware, and antiransomware software are the first line of defense against malicious software. They analyze apps, downloaded files, and system behavior in real time to detect suspicious patterns before the damage is irreversible. A trusted solution adds extra protection to Play Protect or similar native mechanisms.

Anti-theft and device location apps use GPS to show the phone's position if it's lost or stolen. Some allow you to sound an alarm, display messages on the screen, lock the device, or remotely erase data. However, it's important to grant location access only to trusted apps and to review these permissions periodically.

Tools like app locks let you protect access to certain apps with an additional PIN, pattern, or fingerprint. This way, even if someone can unlock your phone, they won't be able to easily access your email, social media, or messaging apps without that second layer of security.

Password managers store your credentials in encrypted form, allowing you to create long and complex passwords without having to remember them. Many automatically generate new passwords, alert you when one has been compromised, and securely sync information across devices, which is especially useful if you use your mobile phone for work.

Two-step verification or multi-factor authentication apps generate one-time codes that strengthen access to your most important accounts. Combined with the good habit of changing passwords regularly, they make it much harder for anyone who manages to steal or buy your credentials on the dark web.

In the realm of browsing, there are privacy-focused browsers and apps that block trackers, filter malicious URLs, reduce intrusive advertising, and make it more difficult for third parties to create a detailed profile of your online habits. These complement ad blockers and phishing detectors, which add extra layers of protection on suspicious websites.

Finally, some organizations offer comprehensive device security analysis apps that review settings, detect malicious or risky apps, and recommend changes to improve your protection. These tools are especially useful if you're not very comfortable with system security settings.

Specific best practices for mobile app developers

Mobile security is not solely the responsibility of users. Developers play a key role in minimizing risks from the very design of their applications. The OWASP Foundation compiles a series of requirements and best practices in its MASVS standard that are worth keeping in mind.

A critical aspect is securely storing sensitive data and preventing data leaks . Apps often handle personal information, session tokens, API keys, or credentials. All of this must be adequately protected, whether stored on internal storage or in areas accessible to other applications.

It is also recommended to use robust cryptographic mechanisms to encrypt sensitive data and properly manage keys throughout their lifecycle: generation, storage, rotation, and revocation. Poorly managed strong cryptography can be almost as dangerous as not encrypting anything at all.

In terms of access control, it's advisable to implement robust authentication and authorization protocols , especially for applications that connect to remote services or perform sensitive operations. It's recommended to separate the initial authentication from additional mechanisms for high-risk actions, for example, by requiring multi-factor authentication for certain transactions.

Communications between the app and its endpoints must be protected using secure protocols such as TLS and strict certificate validation . Furthermore, it is advisable to avoid third-party libraries that weaken this protection by allowing, for example, self-signed certificates without adequate controls or by ignoring validation errors.

Another important aspect is how the app interacts with the mobile platform : IPC mechanisms, WebViews, the graphical interface, screenshots, etc. Poor management of these elements can lead to the exposure of critical data, abuse of internal functions, or information exfiltration through overlay techniques and other common malware tricks.

Finally, good secure development practices include always sanitizing and validating incoming data , using only components without known vulnerabilities, imposing mandatory update mechanisms when critical patches are released, and limiting support to operating system versions that no longer receive security fixes.

Permission control, user privacy, and security audits

In addition to the purely technical aspects, developers must take personal data protection and regulatory compliance very seriously . Regulations such as the European GDPR establish strict obligations that directly impact the design and operation of apps.

A fundamental best practice is to minimize the app's access to sensitive data and resources . Only request the permissions absolutely necessary for the application to function correctly, avoiding requests for access to contacts, location, or camera unless strictly necessary.

It is also advisable to apply data anonymization or pseudonymization techniques so that the information stored or transmitted minimizes the possibility of directly identifying a user. This helps mitigate the impact of a potential security incident.

Transparency is key: users must clearly understand what information the app collects, for what purpose, and for how long . Furthermore, they must be able to manage, modify, and delete their data, as well as easily change their privacy preferences through options accessible within the application itself.

To reinforce these measures, it is very useful to periodically subject applications to security audits . In these reviews, cybersecurity specialists perform static and dynamic tests to identify vulnerabilities in data storage, authentication mechanisms, the use of WebViews, or network connections.

The resulting reports typically include practical recommendations for addressing identified weaknesses , prioritizing those that pose the greatest risk. Incorporating these types of audits into the development lifecycle is one of the best ways to ensure that best practices don't remain merely theoretical.

Ultimately, combining systems like Google Play Protect, specialized security apps, good user practices, and responsible development supported by standards like those of OWASP is the most effective way to enjoy the benefits of mobile apps without turning your smartphone into a constant headache.