Mobile App Security Risks: How to Protect Your App From Common Threats

A mobile app can have a polished interface, strong encryption, and a secure-looking login screen and still leave sensitive data exposed.

The problem is that a mobile app is not just a piece of code running on a phone. It stores and processes data locally, communicates with backend APIs, interacts with the operating system, uses third-party SDKs, and ships a binary that attackers can download and inspect. Every one of those surfaces creates opportunities for abuse.

The risk is becoming harder to ignore. Verizon reports that 85% of organizations surveyed said mobile device attacks were increasing, showing how quickly mobile has become a meaningful part of the broader security landscape.

That makes mobile security risks more than a development concern. A weakness in authentication can lead to account takeover. An insecure API can expose another user’s records. A leaked token can bypass an otherwise secure login flow. A misconfigured WebView or deep link can give an attacker access to functionality the app never intended to expose.

This guide takes a practical route through those risks. Instead of listing security recommendations without context, it explains what each risk looks like, how attackers can exploit it, what damage it can cause, and which controls can reduce the exposure.

Key Takeaways

• The Mobile Attack Surface is Wide: A secure login or polished interface doesn’t protect an app from local storage flaws, compromised APIs, weak session tokens, or vulnerable third-party SDKs.
• Never Trust the Client: Mobile binaries can be reverse-engineered and client-side code can be modified or bypassed. Always enforce authorization, session validation, and business logic on trusted backend servers.
• Treat Data Locally and in Transit: Minimize local storage of sensitive information, utilize platform-secure keystores (like iOS Keychain and Android Keystore), and enforce strict TLS communication policies.
• Secure the API Layer: Since the API is the ultimate backend boundary, protect against Broken Object Level Authorization (BOLA), validate inputs thoroughly, and implement proper rate-limiting.
• Adopt a Framework-Driven Strategy: Leverage established standards like OWASP MASVS and MASTG to guide your security requirements, combine static/dynamic testing, and threat-model your app from architecture to release.

What Are Mobile Security Risks?

Mobile security risks are vulnerabilities, weaknesses, misconfigurations, or design decisions that can allow attackers to access data, accounts, application functionality, backend services, or other protected resources through a mobile application or its surrounding infrastructure.

They can appear in the application itself, but they are not limited to application code.

A typical mobile application may involve:

• Android or iOS application code
• Local databases and files
• Authentication and session tokens
• APIs and backend services
• TLS connections
• Third-party SDKs
• WebViews
• Deep links and universal links
• Android intents and inter-process communication
• Device permissions
• Cryptographic keys
• Application binaries
• Build and release pipelines
• Analytics, advertising, payment, and identity providers

A useful way to understand the attack surface is to connect each surface with what an attacker could gain from it:

This is also where mobile app security differs from simply securing a website. A web application does not normally ship its complete client-side binary to every user or expose the same local storage, device APIs, inter-app communication mechanisms, and mobile platform capabilities.

That difference matters when assessing mobile application security.

Why Are Mobile Apps Vulnerable to Security Threats?

The first issue is the device itself.

Developers do not control the environment in which most users run an application. A phone can be lost, rooted, jailbroken, infected with malicious software, connected to an untrusted network, or shared with other applications.

The application also has to trust several systems outside its own codebase.

Mobile Apps Expose Several Connected Attack Surfaces

Consider a banking application:

1. The user authenticates through the app.
2. The app receives an access token.
3. The token is stored or retained on the device.
4. The app sends requests to an API.
5. The API checks the user’s identity and permissions.
6. The app displays account information.
7. A payment flow may use deep links, WebViews, biometrics, or third-party services.

A weakness at any point can affect the entire flow.

For example, encrypting local data does not fix a broken authorization check on the API. Likewise, strong authentication does not help if a valid session token remains accessible after logout.

That is why mobile security needs to be assessed as a chain rather than a collection of isolated controls.

What Are the Most Common Mobile Security Risks?

The most useful way to assess a mobile security threat is to ask four questions:

• What is vulnerable?
• How could an attacker exploit it?
• What could the attacker gain?
• How can the risk be reduced and tested?

The following risks cover the major attack surfaces developers, security teams, and product owners should evaluate.

1. Insecure Data Storage

Mobile apps often store more information locally than they need.

That can include:

• Authentication tokens
• Personally identifiable information
• User profiles
• Payment-related data
• Passwords or credentials
• Cryptographic keys
• API credentials
• Cached API responses
• Database records
• Temporary files
• WebView data
• Logs and diagnostic information

The danger is not limited to an obviously insecure database. Sensitive information can also leak through caches, backups, temporary files, logs, screenshots, or poorly configured file-sharing mechanisms.

OWASP specifically identifies unencrypted sensitive information in private storage as a mobile application weakness. It also notes that storing a key next to the encrypted data can defeat the purpose of encryption.

A safer approach starts with data minimization. If an application does not need sensitive information on the device, do not store it there.

When data must remain local:

• Use platform-provided secure storage.
• Protect cryptographic keys separately from encrypted data.
• Limit the lifetime of cached information.
• Clear sensitive data when a session ends.
• Restrict file access.
• Avoid putting credentials in logs.
• Review backups and exported files.
• Treat WebView storage as part of the application attack surface.

For example, Android provides the Android Keystore for protecting cryptographic keys, while iOS provides Keychain Services for securely storing small pieces of sensitive information.

The important distinction is that encryption alone is not secure storage. The key-management model matters just as much.

2. Weak Authentication and Session Management

Authentication answers one question:

Who is this user?

A weak authentication flow can allow attackers to guess credentials, abuse account recovery, reuse stolen credentials, bypass verification steps, or maintain access longer than intended.

Mobile applications also need to consider what happens after authentication.

Common session weaknesses include:

• Long-lived access tokens
• Poor refresh-token handling
• Tokens that remain valid after logout
• Missing session expiration
• No re-authentication for sensitive actions
• Weak account recovery
• Inadequate protection against credential stuffing
• Authentication state stored insecurely

A particularly dangerous mistake is treating logout as a purely client-side action. Removing a token from local storage does not necessarily invalidate it on the backend.

A secure session model should define:

• Token lifetime
• Refresh-token rotation
• Server-side revocation
• Re-authentication requirements
• Inactivity timeouts
• Absolute session limits
• Behavior after account or credential changes

For sensitive operations such as changing a password, adding a payment method, transferring money, or changing account ownership, step-up authentication may be appropriate.

Biometric authentication can improve the user experience, but it should not be treated as a replacement for proper server-side authorization.

3. Broken Authorization and Access Control

Authentication and authorization are often confused, but they solve different problems.

Authentication establishes identity.

Authorization determines what that identity is allowed to access.

An application can authenticate users correctly and still have a serious security vulnerability if its authorization model is weak.

Consider an API request such as:

GET /api/orders/18492

If the server returns order 18492 simply because the requester has a valid session, an attacker may be able to change the object identifier and retrieve another user’s order.

This is commonly associated with Broken Object Level Authorization (BOLA).

Other access-control failures include:

• IDOR-style object access
• Broken role-based access control
• Privilege escalation
• Client-side authorization checks
• Missing server-side permission checks
• Broken function-level authorization
• Excessive data returned by an endpoint

The core rule is simple:

Never treat the mobile client as the final authority on what a user is allowed to do.

The backend should verify authorization for every security-sensitive operation.

Hiding a button in the mobile interface is not access control. Checking a role in the app is not sufficient protection. An attacker can modify requests without using the normal interface.

4. Insecure APIs and Backend Services

For many mobile applications, the API is the real security boundary.

The app may have excellent local security and still be vulnerable because the backend accepts requests it should reject.

Common API security weaknesses include:

• Broken authentication
• Broken object-level authorization
• Broken function-level authorization
• Excessive data exposure
• Missing rate limiting
• Unrestricted resource consumption
• Weak input validation
• Predictable object identifiers
• Poor error handling
• Deprecated or undocumented endpoints
• Business-logic abuse
• Unsafe third-party API consumption

The OWASP API Security Top 10 highlights risks such as broken object-level authorization, broken authentication, unrestricted resource consumption, broken function-level authorization, and unrestricted access to sensitive business flows.

This is why API testing should happen independently of testing the mobile interface.

A tester should be able to manipulate requests, change identifiers, remove parameters, alter roles, replay tokens, send unexpected input, and attempt actions outside the normal application flow.

If the API rejects those requests correctly, the backend is enforcing the security boundary.

5. Insecure Communication and Weak SSL/TLS Configuration

Sensitive data should not travel across an unprotected connection.

An attacker positioned between the device and server may attempt to intercept or manipulate traffic, particularly when an application permits cleartext communication or improperly validates certificates.

Potentially exposed information includes:

• Authentication credentials
• Session tokens
• Personal information
• Payment information
• API requests
• Application responses

Modern mobile applications should use HTTPS with properly configured TLS and should explicitly review any exceptions to the platform’s secure networking policies.

Android provides Network Security Configuration for controlling network security behavior, including cleartext traffic and trust configuration.

On Apple platforms, App Transport Security helps enforce secure network connections and minimum security requirements for connections made through supported networking APIs.

Certificate pinning can provide an additional layer of defense in some threat models, but it should not be treated as a universal answer. Poorly implemented pinning can create availability problems during certificate changes, and it does not solve broken authentication or authorization on the backend.

Likewise, TLS protects the transport channel. It does not make an insecure API secure.

6. Hardcoded Credentials and Exposed Secrets

Anything shipped inside a mobile application should be considered potentially discoverable.

Attackers can download an APK, AAB, or IPA and inspect its contents using static analysis and reverse-engineering techniques.

Secrets commonly exposed this way include:

• API keys
• Private keys
• Encryption keys
• Database credentials
• Service-account credentials
• Hardcoded passwords
• Long-lived access tokens
• Internal service URLs

OWASP identifies hardcoded sensitive data in application packages as a specific mobile weakness because anyone who obtains the package can potentially recover those values.

The better architecture is to keep sensitive credentials on trusted backend infrastructure whenever possible.

Public identifiers, such as some client-side API keys intended to identify an application, should not automatically be treated as equivalent to server credentials. Their permissions and exposure model still need to be evaluated.

Code obfuscation can make reverse engineering harder, but it does not turn a hardcoded secret into a secure secret.

7. Reverse Engineering and App Tampering

A mobile application’s binary is distributed to users. That makes it fundamentally different from server-side code.

An attacker can attempt to:

• Decompile the application
• Inspect strings and resources
• Trace application logic
• Modify the binary
• Hook runtime functions
• Bypass client-side checks
• Extract embedded secrets
• Alter business logic
• Create modified application packages

This creates both security and intellectual-property concerns.

Binary protection can increase the effort required to analyze or modify an application. Depending on the threat model, controls may include:

• Code obfuscation
• Application signing
• Integrity checks
• Anti-tampering mechanisms
• Runtime application self-protection
• Root or jailbreak detection
• Debugger detection
• Environment checks

But these controls should be viewed as defense in depth.

If a client-side check determines whether a user can transfer $10,000, an attacker who can modify the client should not be able to bypass the transaction simply by changing that check.

Critical business rules still belong on trusted backend systems.

8. Vulnerable Third-Party SDKs and Dependencies

Your application can inherit a security problem without introducing the vulnerable code yourself.

Mobile applications frequently depend on:

• Analytics SDKs
• Advertising SDKs
• Payment libraries
• Authentication providers
• Crash-reporting tools
• Open-source packages
• Networking libraries
• Image and media frameworks
• Social-login integrations

A vulnerable dependency becomes part of the application you ship.

OWASP notes that third-party components can contain known vulnerabilities and recommends maintaining visibility into dependencies and their provenance.

A practical dependency-security process should include:

The last point matters. Reviewing source dependencies is useful, but the release artifact is what reaches users.

9. Unsafe Use of Mobile Platform Features

Mobile platforms expose powerful mechanisms for apps to communicate with the operating system and other applications.

Those mechanisms can become attack surfaces when they are configured or handled incorrectly.

Examples include:

• Deep links
• Android intents
• Exported activities
• Broadcast receivers
• Content providers
• Universal Links
• URL schemes
• WebViews
• Inter-process communication
• Shared files

Suppose a deep link opens a privileged screen based on a URL parameter. If the app trusts that parameter without validating the user’s authorization, an attacker may be able to invoke functionality through a crafted link.

WebViews create another important boundary. An application that loads untrusted content and exposes powerful JavaScript interfaces can accidentally give web content access to native functionality.

Android’s security guidance recommends restricting WebView navigation and avoiding JavaScript interfaces unless the loaded content is fully trusted.

The same principle applies to platform integrations generally:

Only expose the functionality that another application or external input actually needs.

On Android, exported application components and content providers deserve particular attention. On iOS, developers should carefully validate universal links, URL schemes, shared data, and authentication flows.

10. Excessive Permissions and Privacy Exposure

A permission is not automatically a vulnerability.

The risk comes from requesting more access than the application needs, using that access unnecessarily, or exposing sensitive information through a third-party component.

Common high-impact permissions and capabilities include:

• Location
• Camera
• Microphone
• Contacts
• Photos and files
• Bluetooth
• Notifications
• Health information
• Calendar data

The principle of least privilege applies here.

If an application only needs a user-selected photo, broad access to the entire photo library may be unnecessary. If a feature only needs approximate location, precise location may expose more information than required.

Privacy and security overlap because every additional data source increases the amount of sensitive information the application must protect.

The best permission strategy is therefore not simply “ask for permission securely.” It is to ask whether the application needs that permission at all.

How Do Attackers Exploit Mobile Security Weaknesses?

Individual vulnerabilities become more dangerous when attackers chain them together.

Consider a simplified attack path:

This is why a security review should not stop after finding one issue.

For example, an attacker who extracts a session token from insecure local storage may then use an API authorization weakness to access data belonging to other accounts.

Likewise, a hardcoded API credential may look low impact until the attacker discovers that the associated backend service has broad permissions.

The practical question is not only “Is this vulnerability exploitable?”

It is also:

“What can an attacker do after exploiting it?”

How Can You Protect Your App From Mobile Security Risks?

Protection works best when each risk has a corresponding control.

Security controls should also be placed at the correct trust boundary.

For example:

• Encryption protects data, but key management protects the encryption itself.
• Authentication identifies the user, but authorization controls what the user can access.
• TLS protects data in transit, but API security determines whether the request should be accepted.
• Obfuscation slows reverse engineering, but it does not protect server-side business rules.
• Root detection can identify a higher-risk environment, but it should not replace backend security controls.

For a broader implementation-focused checklist, the existing mobile app security best practices resource can complement this risk-focused guide.

How Should You Test for Mobile Security Risks?

Security testing should not be treated as one final penetration test immediately before launch.

Different risks require different testing methods.

1. Test the Application Binary

Review the release build for:

• Hardcoded secrets
• API credentials
• Debug configurations
• Sensitive strings
• Insecure cryptographic implementations
• Exported components
• Unnecessary permissions
• Embedded endpoints
• Third-party libraries

Static analysis can help identify problems before an attacker discovers them.

2. Test Local Data Storage

Check whether sensitive information appears in:

• Shared preferences
• Databases
• Files
• Caches
• Logs
• Temporary directories
• WebView storage
• Backups
• Clipboard content

Test both normal operation and session termination.

3. Test Authentication and Authorization

Attempt to:

• Reuse expired tokens
• Continue a session after logout
• Access privileged functions as a lower-privileged user
• Change object identifiers
• Replay requests
• Skip authentication steps
• Manipulate role information
• Access another user’s records

The goal is to verify that security decisions remain enforced when the normal user interface is bypassed.

4. Test APIs Independently

Intercept and modify API requests.

Look for:

• BOLA
• Broken function-level authorization
• Excessive data exposure
• Weak authentication
• Missing rate limits
• Input validation failures
• Sensitive error messages
• Replay opportunities
• Business-logic flaws

API testing is particularly important because a mobile client can be modified or replaced entirely by an attacker.

5. Test Network Security

Verify:

• HTTPS enforcement
• No unintended cleartext traffic
• Correct certificate validation
• Secure TLS configuration
• Appropriate handling of certificate failures
• No sensitive information sent to unexpected endpoints

Do not stop at confirming that the URL begins with https://. Test how the application behaves when the connection, certificate, or endpoint is manipulated.

6. Test Platform Interactions

Test:

• Deep links
• Universal Links
• URL schemes
• Android intents
• Exported components
• Content providers
• WebViews
• JavaScript bridges
• IPC
• File sharing
• Permission boundaries

These areas are easy to overlook because the vulnerability may exist in configuration or integration rather than in a traditional application function.

7. Use a Structured Mobile Security Framework

The OWASP Mobile Application Security Testing Guide (MASTG) provides a dedicated framework for mobile security testing and reverse engineering. It maps testing processes to controls and weaknesses covered by the broader OWASP mobile security framework.

A mature testing program can combine:

• SAST
• DAST
• Software Composition Analysis
• Mobile application security testing
• API security testing
• Manual code review
• Penetration testing
• Binary analysis
• Runtime testing
• Threat modeling

The right mix depends on the application’s architecture and risk profile.

Are Mobile Security Risks Different on Android and iOS?

The underlying security problems are similar, but the implementation details differ.

The distinction is important because security controls should use the platform’s intended security mechanisms instead of trying to recreate them in application code.

For example, Apple provides Keychain Services for storing credentials, keys, certificates, and other sensitive information.

At the same time, neither platform’s security model removes the need for secure backend architecture.

A well-sandboxed app can still make an insecure API request.

How Does OWASP Help Identify Mobile Security Risks?

OWASP provides a useful structure for organizing mobile application security work.

The OWASP Mobile Application Security Verification Standard (MASVS) groups security controls into areas including:

• Storage
• Cryptography
• Authentication and authorization
• Network communication
• Platform interaction
• Code quality and updates
• Resilience against reverse engineering and tampering
• Privacy

This gives development and security teams a common vocabulary for reviewing an application.

The important point is that MASVS should be used as a framework, not as a substitute for threat modeling.

An application handling medical records has a different risk profile from a casual mobile game. A banking application needs stronger controls around transactions and account access than a simple content reader.

Security requirements should follow the data, functionality, users, and threat model.

Mobile Security Risks: Quick Reference

Conclusion

Mobile security risks rarely come from one obvious flaw. They emerge across the full application ecosystem: the device, local storage, authentication flow, APIs, network, operating system, third-party components, and application binary.

The most effective approach is to connect every risk to an attack path and a security control. Protect sensitive data where it lives. Enforce authorization on the server. Secure API endpoints instead of trusting the client. Protect communication with properly configured TLS. Keep real secrets out of the application package. Treat third-party SDKs as part of the application’s attack surface. And test the actual application attackers can obtain, modify, and communicate with.

For organizations building or modernizing a mobile product, the security model should be considered alongside the architecture from the beginning. Working with experienced mobile app developers can help ensure security requirements are accounted for across the client, APIs, infrastructure, and release process rather than added after development.

Security is also one part of building a successful mobile application. The goal is not to make an app impossible to attack. That is rarely realistic. The goal is to make sensitive data, accounts, APIs, and critical functionality significantly harder to compromise, while ensuring that one compromised layer does not expose everything behind it.

Frequently Asked Questions

1. What are the most common mobile security risks?

Common mobile security risks include insecure data storage, weak authentication, broken authorization, insecure APIs, hardcoded secrets, insecure communication, app tampering, reverse engineering, vulnerable dependencies, and excessive permissions.

2. What is the biggest security risk for a mobile app?

There is no single biggest risk for every app. The priority depends on the application’s data, architecture, attack surface, and threat model, with broken authorization, insecure APIs, and exposed sensitive data often carrying serious consequences.

3. How can I protect my app from mobile security threats?

Protect sensitive data, secure authentication and authorization, validate API requests, use secure network communication, manage dependencies, and restrict platform permissions. Regular security testing should cover both the mobile application and its backend.

4. What is the difference between authentication and authorization?

Authentication verifies who a user is, while authorization determines what that user can access or do. An authenticated user can still be unauthorized to access another user’s data.

5. How do insecure APIs affect mobile application security?

Insecure APIs can allow attackers to bypass the mobile interface and directly access or manipulate backend resources. Broken authorization, weak authentication, poor input validation, and excessive data exposure are common API security risks.

6. How should mobile apps protect sensitive data?

Avoid storing sensitive data locally unless necessary, and use platform security mechanisms such as Android Keystore or iOS Keychain when appropriate. Encryption, secure key management, access controls, and data minimization further reduce exposure.

7. Is code obfuscation enough to secure a mobile app?

No. Code obfuscation makes reverse engineering more difficult, but critical authentication, authorization, and business-logic decisions should still be enforced by trusted backend systems.

8. What is OWASP MASVS?

OWASP MASVS is a security standard for mobile applications covering areas such as data storage, cryptography, authentication, authorization, network security, platform interaction, resilience, and privacy. It can serve as a baseline for defining and assessing mobile application security requirements.