OWASP Mobile Application Security Testing Guide is a practical testing framework for validating mobile app security. It gives developers and security teams a common way to assess risks across Android and iOS, with controls that map to real-world weaknesses in storage, cryptography, logging, signing, and runtime protection.
What OWASP MASTG Covers
OWASP MASTG is a practical testing guide for mobile application security. It is not just a checklist of weaknesses, it is a structured way to validate whether a mobile app actually resists common failure modes in storage, cryptography, logging, signing, and runtime protection across Android and iOS.
Its value is that it turns mobile security into repeatable verification. Rather than relying on design intent or static review alone, teams use the guide to test the app as it behaves on a real device, in a real build, and under realistic attacker conditions.
How MASTG Fits Into Mobile Security Testing
MASTG sits alongside the OWASP Mobile Application Security Verification Standard, which defines what secure mobile behaviour should look like, while MASTG explains how to test for it. That pairing matters because mobile controls often fail in implementation details, not in the headline architecture.
The guide is especially useful when the same app must behave securely on two operating systems, multiple device states, and different distribution channels. A test that passes on one platform can still fail on the other because the operating system, keystore, entitlement, or runtime protection model differs.
For teams building mobile assurance programmes, the guide helps standardise what “good evidence” looks like. The point is not only to find defects, but to make findings comparable across releases, apps, and business units.
Security Areas MASTG Is Designed to Validate
MASTG focuses on the classes of control failures that most often matter in mobile apps: insecure local storage, weak cryptography, sensitive data exposed in logs or caches, broken certificate handling, unsafe transport behaviour, and tamper resistance gaps. These are practical weaknesses because mobile apps routinely handle tokens, personal data, payment flows, and session material.
It also covers runtime and integrity concerns such as jailbreak or root awareness, dynamic analysis resistance, code tampering, and signing assumptions. Those areas matter because mobile apps operate in environments the defender does not fully control, including user devices, debuggers, emulators, and modified operating systems.
The guide is also relevant to build and release pipelines. Mobile security is not only a runtime problem, it can be introduced earlier through weak signing processes, poor dependency hygiene, or release artefacts that differ from the expected build.
Why OWASP MASTG Matters in Practice
MASTG matters because mobile security failures are often silent until exploitation or reverse engineering reveals them. An app may appear functional while still leaking secrets, trusting the wrong certificate path, or storing sensitive material in ways that are easy to extract from a compromised device.
It also gives developers and testers a shared language. That reduces ambiguity in mobile security reviews, because findings can be tied to a specific test objective instead of a vague “mobile hardening” comment.
Used well, the guide improves consistency across internal assessments, penetration tests, and release gates. It helps security teams ask whether a control exists, whether it is actually enforced, and whether the app still protects data when the device or runtime is hostile.
Risk and Threat Considerations
Mobile apps are exposed to attackers who can inspect the device, instrument the app, intercept traffic, or modify the runtime. The risk is not only data theft, but also tampering with business logic, bypassing controls, or extracting credentials and tokens that let an attacker reuse sessions elsewhere.
Failure mechanism: Weak storage, fragile certificate handling, poor runtime resistance, or insecure signing assumptions let an attacker recover secrets, alter app behaviour, or undermine trust in the application’s outputs.
Impact: The result can include account takeover, data exposure, fraudulent transactions, compromised sessions, and loss of assurance that the released mobile build is the one users actually installed.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP ASVS, CIS Controls v8 and OWASP SAMM set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP ASVS | V11 — Cryptography | MASTG tests mobile cryptography behaviour and implementation weaknesses. |
| V7 — Session Management | MASTG checks mobile session handling, token storage, and reuse risks. | |
| V8 — Authorization | MASTG often validates whether mobile actions and APIs enforce proper access decisions. | |
| Recommendation — Verify mobile cryptography against V11 to confirm strong algorithm use, key handling, and data protection. Test session handling under V7 to prevent token leakage, fixation, and unsafe reuse. Apply V8 checks to confirm the app only exposes functions and data the caller is allowed to access. | ||
| CIS Controls v8 | CIS-16 — Application Software Security | MASTG is a practical mobile app testing guide for validating application security weaknesses. |
| Recommendation — Use CIS-16 to embed mobile security testing into the application security lifecycle. | ||
| OWASP SAMM | Design — Design | MASTG supports secure-by-design mobile verification and testability. |
| Recommendation — Build mobile security tests into design reviews so controls are testable before release. | ||
Practitioner Guidance
Why practitioners should care: MASTG is most useful when it is embedded into mobile release assurance, not treated as an occasional pentest reference. Teams should use it to turn vague mobile security expectations into repeatable test coverage that developers, testers, and security reviewers can all interpret the same way.
What to watch for: The biggest gaps usually appear where the app trusts the client too much, assumes local storage is safe, or relies on platform protections without validating them under hostile conditions. A strong mobile programme tests the same control from multiple angles, because one passing result rarely proves the control is robust.
Practitioner takeaway: Treat MASTG as the execution layer for mobile assurance, while the related verification standard defines the target state.
Related resources from NHI Mgmt Group
- Guide: Mobile App Security Testing Guide
- What are the core risks identified by the OWASP Agentic Top 10?
- How should IAM and AppSec teams work together on OWASP Top 10 findings?
- How should security teams choose an OWASP scanner for modern application delivery?
- When does an OWASP scanner fail to provide meaningful risk reduction?
Deepen Your Knowledge
Free weekly newsletter
Subscribe to the NHI & AI Identity Journal
The latest on NHI and Agentic AI security – articles, research, breaches, news and events every week.
Bonus 33% off our NHI Course when you subscribe.
Reviewed and updated by the NHIMG editorial team on October 31, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org