Client-Side-Only Authorization
← Insecure Authentication / Authorization
client_side_only_authorization MEDIUM
| Category | Insecure Authentication / Authorization |
| OWASP Mobile (2024) | M3 |
| MASVS | MASVS-AUTH-3 |
| MASWE | MASWE-0018 |
| CWE | CWE-602CWE-639 |
| Platform | AndroidiOS |
Description
Admin-only actions gated purely by a client-side boolean flag.
How it works
Admin-only actions are gated solely by a client-side isAdmin flag. An attacker flips the boolean with a tool such as frida or objection, or replays the request; since the server never re-authorizes, the privileged action succeeds. The toggle simulates the flip.
How to exercise it. DVMA is the harness - open this module from the home index and tap the demo action. The screen ships the malicious input and simulates the attacker (e.g. the companion app, crafted intent, or scanned payload) in-process, and the evidence panel prints the proof. The Tools (optional) and Attack inputs below are only needed to reproduce the exploit end-to-end on a real device.
Exploit steps
- Set up. Build DVMA with a flavor that enables the Insecure Authentication / Authorization category (e.g.
--dart-define-from-file=config/flavors/dev.json) and run on an emulator/simulator you control. The demo needs no external tooling; for the optional on-device reproduction the relevant tools are:frida,objection,r2frida. - Locate the target. From the home index, open Client-Side-Only Authorization (
client_side_only_authorization). The How it works section above describes this module’s specific weakness; the screen states the intended-secure behavior and exposes the vulnerable action. - Exploit. Drive the authentication/authorization path, capture the token / assertion / decision, then replay or tamper with it (mitmproxy, a WebAuthn test harness, or by editing the value) and confirm the server-side check accepts the manipulated request.
- Observe the evidence. Trigger the vulnerable action and read the evidence panel - it prints the concrete proof (leaked value, accepted replay, executed payload, or unauthorized result).
- Contrast with the secure path. Run the module’s secure/hardened action (where provided) and confirm the same attack is rejected - this is what a correct implementation should do.