> Source: https://planckproof.ai/mobile-application-testing | Plain-Markdown twin of the page. Mobile API Penetration Testing # The real attack surface behind your mobile app is its API A mobile app is a thin client over REST and GraphQL APIs, and that is where the exploitable impact lives. We extract the endpoints and tokens the app uses, then point Operator at the backend: it tests every operation the app calls for BOLA, BFLA, broken authentication, and business-logic abuse across roles, and proves each finding with a reproducible exploit chain. [Get a Quote](https://planckproof.ai/quote) [Our Methodology](https://planckproof.ai/methodology) Attack Surface ## Every backend operation your app calls The screens users tap are a thin client. Behind them sits an API that authorizes requests, moves money, and holds every account's data. We map that API from the app and test each operation the way an attacker who owns a phone and a valid login would. ### Broken object level authorization (BOLA) The most common and most damaging API flaw behind a mobile app is an endpoint that returns any object when you change the identifier. Operator sends one account's requests with another account's identifiers, walks numeric and UUID object references, and confirms when a user can read or modify records that belong to someone else. Every hit is proven with the exact request and response, not inferred. ### Broken authentication and token handling We test how the backend issues, validates, and expires the tokens the app carries. That includes weak or unsigned JWTs, tokens that outlive logout, refresh flows that never rotate, guessable session identifiers, and endpoints that accept a token minted for a different audience or user. When authentication is the boundary between accounts, we push on every seam in it and prove what gets through. ### Extracting endpoints and tokens Before any testing, we recover the API the app actually talks to. We intercept the app's traffic through a proxy, defeat certificate pinning where it stands in the way, and pull hosts, paths, parameters, headers, and bearer tokens straight from live requests. That inventory becomes the map Operator works from, so testing covers the real backend surface, including undocumented and internal endpoints the app quietly calls. ### Broken function level authorization (BFLA) Mobile clients hide admin and privileged actions behind the interface, but the backend still exposes those operations to anyone who calls them. Operator replays a standard user's session against endpoints and methods meant for administrators, moderators, or service roles, and confirms when the API enforces authorization in the app rather than on the server. Function-level access is a server responsibility, and we test it as one. ### Injection across every parameter Every value the app sends is attacker-controlled once it leaves the device, no matter what validation the client performs. Operator fuzzes each parameter, header, and body field the API exposes for SQL and NoSQL injection, command injection, server-side request forgery, and GraphQL abuse, then carries any promising signal through to confirmed impact. Client-side checks are convenience, not a control, and we test the server as though they were never there. ### Hardcoded secrets and embedded keys API keys, OAuth client secrets, and service credentials shipped inside the package are recoverable by anyone who downloads the app. We search compiled code, string tables, resources, and configuration for embedded secrets, then demonstrate exactly what each recovered value unlocks on the backend, whether it is a third-party service the API trusts or a privileged call the app was never meant to expose. ### The backend APIs behind the app A mobile app is a client for services you run elsewhere, and most exploitable impact lives on the server side of that connection. We test the APIs the app depends on for broken object-level authorization, authentication weaknesses, session handling flaws, and endpoints that trust the client more than they should. A mobile assessment that stops at the binary answers half the question. ### Jailbroken and rooted devices Dynamic testing runs on jailbroken iOS and rooted Android hardware alongside stock devices. That vantage point reflects your actual adversary, who chooses their own equipment, and lets us evaluate your detection controls honestly instead of assuming they hold. Where MASVS resiliency requirements apply, we measure the effort each control adds rather than recording a simple pass or fail. Process ## How a mobile engagement runs Four stages, each with a defined output. You know before testing begins what we will do, on which builds, and against which backend environment. ### Scope, builds, and access We agree on platforms, builds, and a target MASVS level, then arrange access: test accounts across user roles, a backend environment we are authorized to attack, and distribution via TestFlight, IPA, or APK. For white box work we also take source code and build configurations. Rules of engagement are signed before any traffic flows. ### Static and dynamic testing Testers decompile and analyze the binaries, then work through MASTG test cases on jailbroken and rooted devices: storage inspection, traffic interception, runtime instrumentation, IPC probing, and controlled attacks on the backend APIs. Every suspected issue is verified by hand before it is written down. ### Findings and debrief Within five business days of the final day of testing you have the report: an executive summary, verified findings with reproduction steps and evidence, CVSS v3.1 severity ratings, and remediation guidance for each issue. A live debrief call follows, where the testers walk your engineers and leadership through what they found. ### Retest and closure When your fixed builds are ready, we put them back on the same devices for the included retest of every reported finding, then reissue the report with confirmed results. The engagement ends with a document you can hand to customers and auditors, not an open list of known issues. Standards ## A standard you can hold us to Mobile testing here follows the OWASP Mobile Application Security Verification Standard and its companion testing guide. You choose the assurance level, we test to it, and the report states plainly which requirements were exercised. OWASP MASVS OWASP MASTG MASVS-L1 MASVS-L2 MASVS-R CVSS v3.1 ### Testing to a target MASVS level MASVS defines what a secure mobile application looks like; MASTG defines how to verify it. We scope every engagement to a target verification level: MASVS-L1 as the baseline any app should meet, MASVS-L2 for apps handling sensitive data such as payment, health, or credential material, and the MASVS-R resiliency controls where reverse engineering and tampering sit inside your threat model. Findings map to the specific requirements they violate. That gives your team a defensible statement of coverage to show customers and auditors, rather than a vague assurance that the app was tested at some point. - **iOS and Android builds**, including apps built with cross-platform frameworks such as React Native, Flutter, and Kotlin Multiplatform. - **Backend and API dependencies**, covering every endpoint the app communicates with, tested in an environment agreed at scoping. - **Third-party SDKs**, examined for the data they collect, the permissions they inherit, and the transport and storage behavior they introduce into your app. - **Authentication and session handling on device**, from biometric prompts and keychain-backed tokens to session lifetime, refresh logic, and logout behavior. Deliverables ## One report, two audiences The output of a mobile assessment has to serve the leadership deciding which risks to accept and the engineers rebuilding what we broke. Both read the same document, written by the people who did the testing. Delivery happens over an encrypted channel chosen during scoping rather than plain email, and the report and evidence remain yours to retrieve after the engagement closes. - **Executive summary** stating business impact in plain language, suitable for a board or a customer security review. - **Technical findings with reproduction steps and evidence**, including intercepted requests, instrumentation output, and the exact build and device each issue was confirmed on. - **CVSS v3.1 severity ratings** adjusted for context, so a flaw reachable only from a rooted device with local access is rated honestly against one exposed to every installed app. - **Remediation guidance** naming the platform API, entitlement, or configuration to use, not just the weakness to remove. - **Debrief call** with the testers assigned to your engagement, open to your engineers, leadership, and auditors. - **One retest of fixed findings included**, with an updated report issued once your remediation is verified. FAQ ## Mobile testing questions Do you need production builds, or can you test debug builds? Either works, and the best answer is usually both. A release-representative build is essential when resiliency controls are in scope, because obfuscation, pinning, and detection logic often exist only in release configurations. A debug build speeds up instrumentation and lets us spend more of the budget on depth. We typically test the release build for resilience and transport behavior while using a debug build to accelerate everything else, and we agree on the exact builds at scoping. Do you test both iOS and Android? Yes, and most engagements cover both. The platforms differ enough in storage mechanisms, IPC models, and hardening behavior that findings rarely transfer cleanly from one to the other, so each platform gets its own test pass and its own findings. Apps built with cross-platform frameworks such as React Native or Flutter still ship platform-specific packages, and we test those the same way, with additional attention to the framework layer itself. Do you cover the backend APIs the app talks to? Yes, by default. Mobile testing without the API behind it is incomplete, because the binary is only a client and most exploitable impact sits server side. We intercept the app's traffic and test the endpoints it uses for authorization flaws, session handling weaknesses, and excessive trust in client-supplied data. If your API surface is large or shared with web clients, a dedicated [API security assessment](https://planckproof.ai/api-security-testing) can extend that coverage beyond what the mobile app exercises. How do you handle jailbreak and root detection? We treat detection as a control to be measured, not an obstacle to be worked around quietly. Testers attempt to bypass jailbreak and root detection using runtime instrumentation and patching, and the report records how much effort each bypass required. That number matters: detection logic is defense in depth that raises attacker cost, not a boundary that keeps them out, and pretending otherwise produces a misleading report. If your threat model calls for MASVS-R, we assess against those requirements specifically. Do you assess third-party SDKs? Yes, as they behave inside your app. We examine what data each SDK collects and transmits, which permissions and entitlements it inherits, whether its network traffic honors your pinning and TLS posture, and whether it writes sensitive material to storage your own code keeps clean. We do not attack an SDK vendor's infrastructure without authorization, but you receive a clear account of the exposure each dependency introduces and the configuration changes that reduce it. Get Started ## Find out what your app gives away Tell us your platforms and what the app handles. Within a few business days you will have a proposed MASVS target level, engagement model, and start date. [Talk to an Expert](https://planckproof.ai/contact) [Explore Web Application Testing](https://planckproof.ai/web-application-testing)