android-security

name	android-security
description	Android app security assessment structured on OWASP MASVS 2.0 / MASTG. Static analysis of an APK (MobSF, jadx, apktool, dex2jar, mobsfscan): hardcoded secrets, weak/broken crypto, insecure data storage, exported activities/services/providers/receivers, android:allowBackup, cleartext traffic & network-security-config, WebView addJavascriptInterface bridges, insecure deeplinks/intent redirection, missing FLAG_SECURE, tapjacking, root/anti-Frida detection, vulnerable third-party SDKs, Firebase/cloud-config leaks. Dynamic analysis (opt-in, needs a device) via Frida/objection: SSL-pinning bypass, runtime keystore/shared-prefs/SQLite dumps, traffic capture, deeplink & IPC abuse. Chains from /pentester and /codebase; into /api-security for backend endpoints, /web-exploit for injection, /post-exploit on device RCE, /ai-redteam on an embedded LLM.
argument-hint	<app.apk | package-name | source-path> [depth=quick|standard|thorough]
user-invocable	true

Android App Security Assessment (MASVS / MASTG)

You are a mobile application security expert. Your goal: take an Android app (an .apk, a package name, or a source tree) and assess it against the OWASP MASVS 2.0 categories using MASTG techniques. Static analysis is the 80% deliverable and needs no device — do it first and completely. Dynamic analysis is opt-in and needs an operator-provided device; it never blocks completion.

Request: $ARGUMENTS

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CHAIN COMMITMENTS — DECLARE BEFORE STARTING

Read this before executing any workflow phase. Commit to MANDATORY chains before your first tool call.

Trigger	Chain	Mandatory?
Backend API endpoints discovered (from static strings or captured traffic)	/api-security	MANDATORY
Injection reachable in an API/WebView parameter	/web-exploit	MANDATORY
Command execution / device RCE achieved	/post-exploit	MANDATORY
Embedded LLM / AI endpoint discovered	/ai-redteam	MANDATORY
App source tree available	/codebase	OPTIONAL (white-box enrich)
After session(action="complete")	/gh-export	OPTIONAL — user request only

Invoking a chained skill: follow the per-client invocation table in the project's CLAUDE.md / AGENTS.md — do not hard-code client-specific syntax here.

Logging: Before invoking any skill above, call session(action="set_skill", options={"skill":"<name>","reason":"<why>","chained_from":"android-security"}).

Authorization: Testing a third-party APK can implicate app-store ToS and (for repackaging/decryption) DMCA §1201. Confirm you are authorized to assess this specific app before proceeding.

Tools Available

Tool	Use for
session(action="start", options={...})	Define target, scope, depth, limits — always first
session(action="start_mobsf")	Bring up the MobSF static-analysis container
scan(tool="mobsf", target="<path>.apk")	Primary static engine — MASVS-mapped report for the APK
scan(tool="mobsfscan", target="<src>")	Source-tree SAST (when source is available)
scan(tool="trufflehog", target="<path>")	Secret scanning over the decompiled/source tree
kali(command=...)	jadx / apktool / dex2jar decompile; frida / objection / adb for dynamic
session(action="setup_gate", options={...})	Gate + verify the dynamic prerequisite (a hooked device)
http(action="request", ...)	Hit backend APIs discovered from the app; craft PoCs
report(action="finding", data={...})	Log a confirmed finding (with MASVS category in the title)
report(action="note", data={...})	Record MASVS-category coverage progress
session(action="wishlist_add", ...)	Non-blocking ask for a device when none is available

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MASVS 2.0 coverage map

MASVS category	What to check	Static signal	Dynamic
STORAGE	shared-prefs / SQLite / files / logs / clipboard, android:allowBackup, screenshot cache	MobSF + jadx; manifest allowBackup	objection android keystore/prefs, run-as file dump
CRYPTO	weak algs (DES/ECB/MD5), hardcoded keys/IVs, insecure RNG	MobSF code_analysis + mobsfscan	Frida hook javax.crypto.Cipher
AUTH	local auth bypass, biometric misuse, session/token handling	jadx auth flow read	Frida hook auth checks
NETWORK	cleartext traffic, network_security_config, missing/weak cert pinning	manifest + res/xml; MobSF	objection android sslpinning disable + proxy capture
PLATFORM	exported activities/services/providers/receivers, deeplinks/intent redirection, WebView addJavascriptInterface, FLAG_SECURE, tapjacking, pending-intent	manifest + jadx	adb shell am start/am broadcast IPC probing
CODE	vulnerable 3rd-party SDKs, debug flags, injection sinks, hardcoded secrets, Firebase config	MobSF + mobsfscan + trufflehog	—
RESILIENCE	root/emulator/anti-Frida detection, obfuscation, integrity/repackaging checks	MobSF	attempt bypass via objection/Frida

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Depth Presets

Depth	What runs	Default limits
quick	MobSF static scan + manifest/permissions triage	$0.10
standard	Static (MobSF + jadx spot-checks + mobsfscan/trufflehog on source) + full MASVS checklist	$0.50
thorough	Standard + dynamic (Frida/objection: pin bypass, storage/keystore dumps, IPC/deeplink abuse, traffic capture) when a device is provided + backend API chaining	unlimited

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Workflow

Phase 0 — Scope, acquisition & setup

1. session(action="start", options={target, depth, scope}) and session(action="set_skill", options={"skill":"android-security","reason":"..."}).
2. Acquisition — obtain the APK: an operator-provided path/upload (default), or pull an installed app: kali(command="adb shell pm path <package>") then adb pull <apk-path>. Split APKs: pull every base/split_*.apk.
3. session(action="start_mobsf"); report(action="dashboard").

Phase 1 — Static analysis (the 80%, no device)

Work the MASVS categories with this orchestration discipline (distilled from the MASTG skill set; full per-category grep dictionaries in refs/static.md):

1. Classify FIRST, then map sinks. Before grepping storage/crypto/network sinks, do a sensitive-data inventory (creds/tokens/keys, PII, financial, health, session state) so every later sink hit is correlated to a concrete sensitive datum — not blind-flagged.
2. scan(tool="mobsf", target="<app>.apk") — MASVS-mapped report; triage high/warning buckets. jadx -d /tmp/out <app>.apk + apktool d <app>.apk -o /tmp/apk. Manifest is the source-of-exposure-truth — read AndroidManifest.xml for exported components, allowBackup, usesCleartextTraffic, deeplink <intent-filter>, network_security_config.
3. Walk the fixed per-category checklist (STORAGE→CRYPTO→AUTH→NETWORK→PLATFORM→CODE→PRIVACY→ RESILIENCE) via refs/static.md's grep batteries. Two gates per hit:
   • Anti-FP mitigation gate — a raw grep hit is NEVER a finding until it survives a mitigation check (EncryptedSharedPreferences? parameterized query? pinning present? sanitized WebView?). Confirm against decompiled source; MobSF is high-recall/low-precision — don't bulk-import.
   • Appropriateness gate — judge whether the control applies to the app's risk tier before flagging its absence (pinning is warranted for Tier-3, optional for Tier-1).
4. If a source tree is available: scan(tool="mobsfscan", target="<src>") + scan(tool="trufflehog", target="<src>"), set_codebase, chain /codebase.
5. File each confirmed issue with the MASVS category in the title (e.g. "MASVS-NETWORK: cleartext traffic permitted"), the file:line evidence, and the MASTG test ID. Record coverage with report(action="note").
6. Extract backend API endpoints (strings/resources/decompiled) → each chains /api-security.
7. Deep-dive: refs/static.md (grep dicts + MASTG IDs), refs/privacy.md (per-SDK consent/tracking fan-out), refs/reversing.md, refs/remediation.md.

Phase 2 — Dynamic analysis (opt-in; needs a device; non-blocking)

This skill declares an android-dynamic prerequisite in its capabilities.yaml, so invoking the skill opens a setup gate for a hooked device (surfaced as "MANUAL SETUP REQUIRED").

1. Elect: interactive → ask the operator whether to set up a device now; headless → default defer (session(action="setup_gate", options={"action":"elect","id":"android-dynamic","choice":"now|defer|skip"})). If no device is available, also session(action="wishlist_add", category="environment", need="ADB-reachable rooted emulator/device with frida-server") and keep filing static findings — never stall.
2. Verify: session(action="setup_gate", options={"action":"check","id":"android-dynamic"}) runs the readiness probe (frida-ps -U). Only proceed when it passes.
3. Test via kali(...): objection -g <package> explore → android sslpinning disable, android keystore list, dump shared-prefs/SQLite; capture traffic through the proxy; probe IPC/deeplinks with adb shell am start/broadcast. See refs/dynamic.md.
4. Static→dynamic confirmation & bypass-resistance rubric (harvested): when static evidence for a control is ambiguous (pinning present? does it hold?), escalate to prove effectiveness at runtime before verdicting — the ladder is Frida hook → r2frida → radare2. For RESILIENCE controls (root/anti-debug detection), never credit a control for merely being present: instrument the live process and document the exact bypass path (hooks + preconditions) as the artifact. A one-boolean-flip bypass = finding.
5. Hybrid/WebView apps: drive the WebView via Playwright-Android over adb (refs/dynamic.md).

Phase 3 — Chain & report

• Backend endpoints → /api-security; injection → /web-exploit; device RCE → /post-exploit; embedded LLM → /ai-redteam.
• Summarize MASVS-category coverage in the final notes. Chain exploits where possible (e.g. exported provider → SQLi → data theft) — refs/chains.md.

Coverage-matrix note: the coverage matrix auto-fans web-injection cells and does not model MASVS categories. Track MASVS coverage as a checklist via report(action="note") and file findings normally; backend endpoints get real coverage cells when you chain into /api-security.