Obfuscapk : Black-Box Obfuscation Tool For Android Apps

NinjaDroid is a simple tool to reverse engineering Android APK packages.

$ snap install ninjadroid –channel=beta

Overview

NinjaDroid uses AXMLParser together with a series of Python scripts based on aaptkeytool, string and such to extract a series of information from a given APK package, such as:

  • List of files of the APK: file name, size, MD5, SHA-1, SHA-256 and SHA-512
  • AndroidManifest.xml info: app name, package name, version, sdks, permissions, activities, services, broadcast-receivers, …
  • CERT.RSA/DSA digital certificate info: serial number, validity, fingerprint, issuer and owner
  • List of URLs, shell commands and other generic strings hard-coded into the classes.dex files

Furthermore, NinjaDroid uses apktool and dex2jar to extract and store:

  • JSON report file, which contains all the extracted APK info
  • AndroidManifest.xml file (thanks to apktool)
  • CERT.RSA/DSA digital certificate file
  • classes.dex files
  • translated .jar file (thanks to dex2jar)
  • disassembled smali files (thanks to apktool)
  • assets/ and res/ folders together with their content (thanks to apktool)

Installation

The first step is cloning the NinjaDroid repository, or downloading its source code.

$ git clone https://github.com/rovellipaolo/NinjaDroid
$ cd NinjaDroid

NinjaDroid has several ways to be executed: natively in your local environment, in Docker, as a Flatpak (experimental) and as a Snap (experimental).

Native

To execute NinjaDroid in your local machine, you need to install Python 3.5 or higher, Java 8 or higher and binutils.

Optionally, if you have the Android SDK installed locally, you can use the SDK version of aapt instead of the included one. In order to do so, you need to change the aapt location in ninjadroid/aapt/Aapt.py (i.e. __AAPT_EXEC_PATH = "ninjadroid/aapt/aapt").

Linux

Just launch the following commands, which will install all the Python dependencies (making sure that aaptapktool and dex2jar have executable permissions) and add a ninjadroid symlink to /usr/local/bin/.

$ make build-linux
$ make install
$ ninjadroid –help

MacOS

Just launch the following commands, which will install all the needed Python dependencies (making sure that aaptapktool and dex2jar have executable permissions) and add a ninjadroid symlink to /usr/local/bin/.

$ make build-macos
$ make install
$ ninjadroid –help

Docker

To execute NinjaDroid in Docker, you need Docker installed.

To build the Docker image, launch the following commands:

$ make build-docker
$ docker run –name ninjadroid ninjadroid:latest ninjadroid –help

Note that you need to bind the directory containing the target APK package to the Docker image:

$ mkdir apks
$ cp /path/to/your/package.apk apks/package.apk
$ docker run –name ninjadroid -it –rm -v $(pwd)/apks:/apks ninjadroid:latest ninjadroid /apks/package.apk -aj

And the same applies also to the output directory when using the -e/--extract option, to which you also need to grant permissions:

$ mkdir output
$ chmod 777
$ docker run –name ninjadroid –rm -v $(pwd)/apks:/apks -v $(pwd)/output:/output ninjadroid:latest ninjadroid /apks/package.apk -ae /output

Flatpak (experimental)

To execute NinjaDroid as a Flatpak, you need Flatpak and flatpak-builder installed.

Just launch the following commands, which will install all the needed Flatpak dependencies:

$ make build-flatpak
$ flatpak-builder –run flatpak/build flatpak/com.github.rovellipaolo.NinjaDroid.yaml ninjadroid –help

NOTE: The -e/--extract option does not work correctly at present (see: https://github.com/rovellipaolo/NinjaDroid/issues/21).

Snap (experimental)

To execute NinjaDroid as a Snap, you need Snap and snapcraft installed.

Just launch the following commands, which will install all the needed Snap dependencies:

$ make build-snap
$ make install-snap
$ ninjadroid –help

NOTE: The -e/--extract option does not work correctly when the snap is installed without using the --devmode option (see: https://github.com/rovellipaolo/NinjaDroid/issues/20).

Checkstyle

Once you’ve configured it (see the “Installation” section), you can also run NinjaDroid checkstyle as follows.

Native

To run the checkstyle in your local machine, launch the following command:

$ make checkstyle

NOTE: This is using pylint under-the-hood.

You can also run the checkstyle automatically at every git commit by launching the following command:

$ make install-githooks

Docker

To run the checkstyle in Docker, launch the following command:

$ make checkstyle-docker

Tests

Once you’ve configured it (see the “Installation” section), you can also run NinjaDroid tests as follows.

Native

To run unit and regression tests in your local machine, launch the following commands:

$ make test
$ make regression

You can also run the tests with coverage by launching the following command:

$ make test-coverage

Docker

To run unit and regression tests in Docker, launch the following commands:

$ make test-docker
$ make regression-docker

Flatpak

To run regression tests in Flatpak, launch the following command:

$ make regression-flatpak

Snap

To run regression tests in Snap, launch the following command:

$ make regression-snap

Usage

The following are examples of running NinjaDroid against the sample APK package.

Show APK summary

$ ninjadroid regression/data/Example.apk

file: regression/data/Example.apk
size: 70058
md5: c9504f487c8b51412ba4980bfe3cc15d
sha1: 482a28812495b996a92191fbb3be1376193ca59b
sha256: 8773441a656b60c5e18481fd5ba9c1bf350d98789b975987cb3b2b57ee44ee51
sha512: 559eab9840ff2f8507842605e60bb0730442ddf9ee7ca4ab4f386f715c1a4707766065d6f0b977816886692bf88b400643979e2fd13e6999358a21cabdfb3071
name: Example
cert:
file: META-INF/CERT.RSA
size: 906
md5: 860e19fa47d37d9510f1245c511a8578
sha1: 59a04084c0d5ef23fd05f0f429dab6267ccb3d0b
sha256: 0efa622919417adfa6eb77770fd33d3bcd93265ac7343695e246dab1a7b6bfee
sha512: 2a5befcc0bcb14e44d7b7cb4322a76933ad3e90e5e1ffbb87ba31ee7cc0172725dcc98e9d414fb3a207bc107b2a7ca7563b5f954cac6bd41d77e4726c70a95a3
manifest:
file: AndroidManifest.xml
size: 6544
md5: 1f97f7e7ca62f39f8f81d79b1b540c37
sha1: 011316a011e5b8738c12c662cb0b0a6ffe04ca74
sha256: 7c8011a46191ecb368bf2e0104049abeb98bae8a7b1fa3328ff050aed85b1347
sha512: 8c7c1ede610f9c6613418b46a52a196ad6d5e8cc067c2f26b931738ad8087f998d9ea95e80ec4352c95fbdbb93a4f29c646973535068a3a3d584da95480ab45f
package: com.example.app
version:
code: 1
name: 1.0
sdk:
min: 10
target: 20
max: 20
permissions:
– android.permission.INTERNET
– android.permission.READ_EXTERNAL_STORAGE
– android.permission.RECEIVE_BOOT_COMPLETED
– android.permission.WRITE_EXTERNAL_STORAGE
dex:
file: classes.dex
size: 2132
md5: 7bc52ece5249ccd2d72c4360f9be2ca5
sha1: 89476799bf92798047ca026c922a5bc33983b008
sha256: 3f543c68c4c059548cec619a68f329010d797e5e4c00aa46cd34c0d19cabe056
sha512: 0725f961bc1bac47eb8dd045c2f0a0cf5475fd77089af7ddc3098e341a95d8b5624969b6fa47606a05d5a6adf9d74d0c52562ea41a376bd3d7d0aa3695ca2e22

Show APK extended information in JSON format

$ ninjadroid regression/data/Example.apk –all –json

{
“cert”: {
“file”: “META-INF/CERT.RSA”,
“fingerprint”: {
“md5”: “”,
“sha1”: “5A:C0:6C:32:63:7F:5D:BE:CA:F9:38:38:4C:FA:FF:ED:20:52:43:B6”,
“sha256”: “E5:15:CC:BC:5E:BF:B2:9D:A6:13:03:63:CF:19:33:FA:CE:AF:DC:ED:5D:2F:F5:98:7C:CE:37:13:64:4A:CF:77”,
“signature”: “SHA1withRSA”,
“version”: “3”
},
“issuer”: {
“city”: “City”,
“country”: “XX”,
“domain”: “”,
“email”: “”,
“name”: “Name”,
“organization”: “Organization”,
“state”: “State”,
“unit”: “Unit”
},
“md5”: “860e19fa47d37d9510f1245c511a8578”,
“owner”: {
“city”: “City”,
“country”: “XX”,
“domain”: “”,
“email”: “”,
“name”: “Name”,
“organization”: “Organization”,
“state”: “State”,
“unit”: “Unit”
},
“serial_number”: “558e7595”,
“sha1”: “59a04084c0d5ef23fd05f0f429dab6267ccb3d0b”,
“sha256”: “0efa622919417adfa6eb77770fd33d3bcd93265ac7343695e246dab1a7b6bfee”,
“sha512”: “2a5befcc0bcb14e44d7b7cb4322a76933ad3e90e5e1ffbb87ba31ee7cc0172725dcc98e9d414fb3a207bc107b2a7ca7563b5f954cac6bd41d77e4726c70a95a3”,
“size”: 906,
“validity”: {
“from”: “2015-06-27 10:06:13Z”,
“until”: “2515-02-26 10:06:13Z”
}
},
“dex”: [
{
“file”: “classes.dex”,
“md5”: “7bc52ece5249ccd2d72c4360f9be2ca5”,
“sha1”: “89476799bf92798047ca026c922a5bc33983b008”,
“sha256”: “3f543c68c4c059548cec619a68f329010d797e5e4c00aa46cd34c0d19cabe056”,
“sha512”: “0725f961bc1bac47eb8dd045c2f0a0cf5475fd77089af7ddc3098e341a95d8b5624969b6fa47606a05d5a6adf9d74d0c52562ea41a376bd3d7d0aa3695ca2e22”,
“shell_commands”: [
“set”
],
“size”: 2132,
“strings”: [
“!Lcom/example/app/ExampleService2;”,
“!Lcom/example/app/ExampleService3;”,
“#Landroid/content/BroadcastReceiver;”,
“)Lcom/example/app/ExampleBrodcastReceiver;”,
Lcom/example/app/ExampleBrodcastReceiver2;”, “Lcom/example/app/ExampleBrodcastReceiver3;”,
“*Lcom/example/app/ExampleBrodcastReceiver4;”,
“”,
“Landroid/app/Activity;”,
“Landroid/app/Service;”,
“Landroid/content/Context;”,
“Landroid/content/Intent;”,
“Landroid/os/Bundle;”,
“Landroid/os/IBinder;”,
“Lcom/example/app/ExampleService;”,
“Lcom/example/app/HomeActivity;”,
“Lcom/example/app/OtherActivity;”,
“onBind”,
“onCreate”,
“onReceive”,
“setContentView”
],
“urls”: []
}
],
“file”: “regression/data/Example.apk”,
“manifest”: {
“activities”: [
{
“intent-filter”: [
{
“action”: [
“android.intent.action.MAIN”
],
“category”: [
“android.intent.category.LAUNCHER”
]
}
],
“launchMode”: “1”,
“name”: “com.example.app.HomeActivity”
},
{
“intent-filter”: [
{
“action”: [
“android.intent.action.VIEW”
],
“category”: [
“android.intent.category.DEFAULT”
],
“data”: [
{
“scheme”: “content”
},
{
“scheme”: “file”
},
{
“mimeType”: “application/vnd.android.package-archive”
}
]
}
],
“launchMode”: “1”,
“meta-data”: [
{
“name”: “android.support.PARENT_ACTIVITY”,
“value”: “com.example.app.HomeActivity”
}
],
“name”: “com.example.app.OtherActivity”,
“noHistory”: “true”,
“parentActivityName”: “com.example.app.HomeActivity”
}
],
“file”: “AndroidManifest.xml”,
“md5”: “1f97f7e7ca62f39f8f81d79b1b540c37”,
“package”: “com.example.app”,
“permissions”: [
“android.permission.INTERNET”,
“android.permission.READ_EXTERNAL_STORAGE”,
“android.permission.RECEIVE_BOOT_COMPLETED”,
“android.permission.WRITE_EXTERNAL_STORAGE”
],
“receivers”: [
{
“name”: “com.example.app.ExampleBrodcastReceiver”
},
{
“exported”: false,
“intent-filter”: [
{
“action”: [
“android.intent.action.BOOT_COMPLETED”,
“android.intent.action.MY_PACKAGE_REPLACED”
],
“priority”: “1000”
}
],
“name”: “com.example.app.ExampleBrodcastReceiver2”
},
{
“enabled”: true,
“exported”: false,
“intent-filter”: [
{
“action”: [
“android.intent.action.BROADCAST_PACKAGE_REMOVED”,
“android.intent.action.PACKAGE_ADDED”,
“android.intent.action.PACKAGE_REPLACED”
],
“data”: [
{
“scheme”: “package”
}
],
“priority”: “800”
}
],
“name”: “com.example.app.ExampleBrodcastReceiver3”
},
{
“enabled”: false,
“exported”: true,
“name”: “com.example.app.ExampleBrodcastReceiver4”
}
],
“sdk”: {
“max”: “20”,
“min”: “10”,
“target”: “20”
},
“services”: [
{
“name”: “com.example.app.ExampleService”
},
{
“enabled”: false,
“exported”: true,
“isolatedProcess”: true,
“name”: “com.example.app.ExampleService2”
},
{
“enabled”: true,
“exported”: false,
“isolatedProcess”: false,
“name”: “com.example.app.ExampleService3”
}
],
“sha1”: “011316a011e5b8738c12c662cb0b0a6ffe04ca74”,
“sha256”: “7c8011a46191ecb368bf2e0104049abeb98bae8a7b1fa3328ff050aed85b1347”,
“sha512”: “8c7c1ede610f9c6613418b46a52a196ad6d5e8cc067c2f26b931738ad8087f998d9ea95e80ec4352c95fbdbb93a4f29c646973535068a3a3d584da95480ab45f”,
“size”: 6544,
“version”: {
“code”: 1,
“name”: “1.0”
}
},
“md5”: “c9504f487c8b51412ba4980bfe3cc15d”,
“name”: “Example”,
“other”: [
{
“file”: “res/drawable-hdpi-v4/ic_launcher.png”,
“md5”: “e74dbf28ebab4e1b7442a9c78067d1c2”,
“sha1”: “450d3d44325fdf259810a60e6afa36103e186b3d”,
“sha256”: “9b2639dbfdd60e0dab70e572f39660c8dfabd19b7987a7619d770824db342925”,
“sha512”: “44050c4db6d5275b70856050c0d58d3d9892ba09bd8cf1a8343a3c6d4f2e2af6eae1f8b687efb59b7f8122e5bea1a63e08546fee35124cc0faab40ef6274ab4f”,
“size”: 9193
},
{
“file”: “res/drawable-hdpi-v4/ic_launcher_logo.png”,
“md5”: “e74dbf28ebab4e1b7442a9c78067d1c2”,
“sha1”: “450d3d44325fdf259810a60e6afa36103e186b3d”,
“sha256”: “9b2639dbfdd60e0dab70e572f39660c8dfabd19b7987a7619d770824db342925”,
“sha512”: “44050c4db6d5275b70856050c0d58d3d9892ba09bd8cf1a8343a3c6d4f2e2af6eae1f8b687efb59b7f8122e5bea1a63e08546fee35124cc0faab40ef6274ab4f”,
“size”: 9193
},
{
“file”: “res/drawable-ldpi-v4/ic_launcher.png”,
“md5”: “58b9a42eeb99fad5321208fe02f24375”,
“sha1”: “09ea65885b4080e515ef7064e816c77991c0757b”,
“sha256”: “c4f061b2c758185371f39afcb166ba039e955d3be2619ab5469a1b873f952d0d”,
“sha512”: “415ed16de6fd335b24bd985d9152323d04fc02287acd3f26fa98722832cfecf89cf2c77ad8ae3f5588acc5cac401129ac3b3d714abbf8dcc492ab2fd98f106e5”,
“size”: 2658
},
{
“file”: “res/drawable-ldpi-v4/ic_launcher_logo.png”,
“md5”: “58b9a42eeb99fad5321208fe02f24375”,
“sha1”: “09ea65885b4080e515ef7064e816c77991c0757b”,
“sha256”: “c4f061b2c758185371f39afcb166ba039e955d3be2619ab5469a1b873f952d0d”,
“sha512”: “415ed16de6fd335b24bd985d9152323d04fc02287acd3f26fa98722832cfecf89cf2c77ad8ae3f5588acc5cac401129ac3b3d714abbf8dcc492ab2fd98f106e5”,
“size”: 2658
},
{
“file”: “res/drawable-mdpi-v4/ic_launcher.png”,
“md5”: “acefc1f320111a8d71bcdb8b4aa0656c”,
“sha1”: “23730fd0d5e720d1f719be1afc8c48fa7305da6c”,
“sha256”: “05346d62d4096537906928af523ef9d5997663707a1d48e08f20992584e1424d”,
“sha512”: “59896fc52679e86898dc09b56fb53270d4297c53adee26f864657c5ef4aff9e5f5922dfa9370c3d1748068aa7b1270e0fa8a1323ce3b69c7548a50ca221befc1”,
“size”: 5057
},
{
“file”: “res/drawable-mdpi-v4/ic_launcher_logo.png”,
“md5”: “acefc1f320111a8d71bcdb8b4aa0656c”,
“sha1”: “23730fd0d5e720d1f719be1afc8c48fa7305da6c”,
“sha256”: “05346d62d4096537906928af523ef9d5997663707a1d48e08f20992584e1424d”,
“sha512”: “59896fc52679e86898dc09b56fb53270d4297c53adee26f864657c5ef4aff9e5f5922dfa9370c3d1748068aa7b1270e0fa8a1323ce3b69c7548a50ca221befc1”,
“size”: 5057
},
{
“file”: “res/drawable-xhdpi-v4/ic_launcher.png”,
“md5”: “94f5591633218c0b469b65947fd8943b”,
“sha1”: “502cd84fa444f26d7ecfdf4a355064867977f236”,
“sha256”: “29d15992424b40757135f47fc8ddd15e30c7774646b37755608f7cfec1df7d8a”,
“sha512”: “d5b48e065a614c5a2400b6565dc36777d9923d8d5154487113dd1f46b05d36d1db3f28fb72f61a68fcbd225c93495541579574e6611f650fe2857767412c3b1f”,
“size”: 14068
},
{
“file”: “res/drawable-xhdpi-v4/ic_launcher_logo.png”,
“md5”: “94f5591633218c0b469b65947fd8943b”,
“sha1”: “502cd84fa444f26d7ecfdf4a355064867977f236”,
“sha256”: “29d15992424b40757135f47fc8ddd15e30c7774646b37755608f7cfec1df7d8a”,
“sha512”: “d5b48e065a614c5a2400b6565dc36777d9923d8d5154487113dd1f46b05d36d1db3f28fb72f61a68fcbd225c93495541579574e6611f650fe2857767412c3b1f”,
“size”: 14068
},
{
“file”: “res/layout/main.xml”,
“md5”: “8cdec0105448937475e45e22c80fd611”,
“sha1”: “51ebf14ed21238f7d147a6744cae18c0f55fcbe6”,
“sha256”: “e74db1ac37395ca9fd25b93261d3ab76ed7dfc9b355ea63d856afc7453313738”,
“sha512”: “2d2147365b8b00f2db7498b7f0ed8a360fc15bd43dfd3704b4b1cb912619d9ff1bc35837eb1e601ea6d1aa3a8c0d555f2105d6ed37de919fa128568527765d63”,
“size”: 552
},
{
“file”: “resources.arsc”,
“md5”: “2886f2825eef3b5c4478852935c68640”,
“sha1”: “1eff126288b4bea6fa78eb79832d6a7fa098695e”,
“sha256”: “ac46f54fa12dc20e94619465482186047505fb9f27508861220063c93f0c6c4e”,
“sha512”: “da8c41d0c27839ed89cb06a2f89f6993bd88f5179e97f3291f0e17348868b3e9c106e96f482ecd86f11808170937773e7599ccd338900908359e870ea5446169”,
“size”: 1640
},
{
“file”: “META-INF/MANIFEST.MF”,
“md5”: “6098a6409625f1c0d97cd33c13ad300c”,
“sha1”: “ccfe31190feb259a4a56599ad1403a956f6944b5”,
“sha256”: “8a18f285481346919f4df55f576ee504bf5abecb068a2d642fdef17f3b5cd631”,
“sha512”: “17a68bf605aff149aa31e1b0b81af3d3f74f939e1cb7a10f3eddf84775f901b09ba9722efad1265b0057cdfcd12c6fac701067993081620b00bbfcc4efff3599”,
“size”: 1061
},
{
“file”: “META-INF/CERT.SF”,
“md5”: “fb02917b68510e413a06e52873802bcd”,
“sha1”: “dfb7bbb487010b980152610fe7d669c1b4f626be”,
“sha256”: “e2fa373f8b065ef7c78387ab9242e98dd19bdeb2b768295506295f7beb0bfe3f”,
“sha512”: “3aa74603588ca5c563b6586d1216dc6cea3b8d2a1a47eb189197e8f20cd7508d3e652c7ff849261e95cff52451476b2993caadf051fdf66cc01f5e6e16b180fc”,
“size”: 1114
}
],
“sha1”: “482a28812495b996a92191fbb3be1376193ca59b”,
“sha256”: “8773441a656b60c5e18481fd5ba9c1bf350d98789b975987cb3b2b57ee44ee51”,
“sha512”: “559eab9840ff2f8507842605e60bb0730442ddf9ee7ca4ab4f386f715c1a4707766065d6f0b977816886692bf88b400643979e2fd13e6999358a21cabdfb3071”,
“size”: 70058
}

Extract and store APK entries and information

$ ninjadroid regression/data/Example.apk –all –extract output/

NinjaDroid: [INFO] Executing apktool…
NinjaDroid: [INFO] Creating output/smali/…
NinjaDroid: [INFO] Creating output/AndroidManifest.xml…
NinjaDroid: [INFO] Creating output/res/…
NinjaDroid: [INFO] Creating output/assets/…
NinjaDroid: [INFO] Executing dex2jar…
NinjaDroid: [INFO] Creating output/Example.jar…
dex2jar regression/data/Example.apk -> output/Example.jar
NinjaDroid: [INFO] Extracting certificate file…
NinjaDroid: [INFO] Creating output/META-INF/CERT.RSA…
NinjaDroid: [INFO] Extracting DEX files…
NinjaDroid: [INFO] Creating output/classes.dex…
NinjaDroid: [INFO] Generating JSON report file…
NinjaDroid: [INFO] Creating output/report-Example.json…

NOTE: without specifying an output directory, one with the APK package name will be created inside the current working directory.