Mobile Backend APIs
Mobile apps talk to APIs. We listen.
Testing APIs that support mobile applications, focusing on certificate pinning bypass, API key exposure, and mobile-specific attack vectors.
Overview
Mobile applications present unique API security challenges. The client runs on untrusted devices, API keys are embedded in decompilable code, and certificate pinning creates false confidence. Mobile Backend API Testing examines your APIs from the perspective of an attacker with full access to your mobile application—because that's exactly what every user has.
What We Test
Our mobile backend apis engagements cover these key areas:
Certificate pinning implementation and bypass
API key and secret extraction from mobile binaries
Authentication token handling on mobile platforms
Sensitive data exposure in API responses
Server-side session validation
Rate limiting and anti-automation controls
Our Approach
Mobile backend testing combines API security testing with mobile application reverse engineering. We intercept and analyze traffic between your app and servers, extract embedded secrets, and test APIs as a hostile client would.
Application Analysis
Reverse engineer mobile applications to understand API communication patterns, extract embedded credentials, and identify hardcoded endpoints.
Traffic Interception
Set up MITM proxy to intercept API traffic. Bypass certificate pinning if implemented to capture and modify API requests.
Credential Extraction
Extract API keys, client secrets, and other credentials from application binaries. Test whether server-side controls prevent abuse if these are compromised.
API Security Testing
Apply full REST API security testing methodology to discovered endpoints, with focus on mobile-specific concerns like device attestation and session handling.
Anti-Tampering Evasion
Test effectiveness of anti-tampering, root/jailbreak detection, and other client-side security controls that mobile apps often rely upon.
Data Storage Analysis
Examine how the mobile app stores tokens, credentials, and sensitive data. Verify that server-side controls don't trust client-side security.
Common Findings
These are issues we frequently discover during mobile backend apis engagements:
API keys in mobile binaries
API keys or client secrets embedded in mobile applications that can be extracted through simple decompilation. No client-side secret is truly secret.
Bypassable certificate pinning
Certificate pinning implemented but easily bypassed with common tools like Frida or Objection, providing false confidence in transport security.
Excessive trust in client
Server-side APIs trust client-provided data that could be manipulated—pricing, user roles, or business logic parameters.
Missing server-side validation
Validation only performed in mobile app code. Attackers bypassing the app can submit invalid data directly to APIs.
Sensitive data in responses
APIs return more data than the mobile app displays, exposing sensitive information to anyone who intercepts traffic.
Common Questions
Do you test both iOS and Android?
Yes. iOS and Android apps often share the same backend but may have different security implementations. We test both platforms to ensure consistent security posture.
Can you bypass certificate pinning?
In most cases, yes. Certificate pinning raises the bar but is bypassable on rooted/jailbroken devices. We test whether your API security assumes pinning will work—it shouldn't.
What if our API keys are in the app?
They can be extracted. The question is whether your server-side controls prevent abuse. We test what an attacker could do with extracted credentials—rate limiting, IP restrictions, and anomaly detection should limit damage.
Should we not use API keys in mobile apps?
API keys in mobile apps aren't secrets—they're identifiers. Use them for client identification, but don't rely on them for security. Implement proper user authentication and server-side authorization instead.
Other API Security Testing Options
REST API Testing
Comprehensive testing of RESTful APIs for authentication bypass, injection flaws, broken object-level authorization, and data exposure.
GraphQL Security
Specialized testing for GraphQL APIs including introspection attacks, query complexity abuse, and authorization bypass.
SOAP/XML Services
Legacy web service testing for XML injection, SOAP action spoofing, and WS-Security implementation flaws.
OAuth/OIDC Assessment
Authentication flow testing for OAuth 2.0 and OpenID Connect implementations, including token handling and redirect vulnerabilities.
Ready to Strengthen Your Defenses?
Schedule a free consultation with our security experts to discuss your organization's needs.
Or call us directly at (445) 273-2873