Port MASTG-TEST-0001 (by @guardsquare)

Document/0x05d-Testing-Data-Storage.md

@@ -39,23 +39,14 @@ Understanding each relevant data storage function is crucial for performing the
 
 ### Shared Preferences
 
-The [SharedPreferences](https://developer.android.com/training/data-storage/shared-preferences "Shared Preferences") API is commonly used to permanently save small collections of key-value pairs. Data stored in a SharedPreferences object is written to a plain-text XML file. The SharedPreferences object can be declared world-readable (accessible to all apps) or private.
-Misuse of the SharedPreferences API can often lead to exposure of sensitive data. Consider the following example:
+The [`SharedPreferences`](https://developer.android.com/training/data-storage/shared-preferences "Shared Preferences") API is commonly used to permanently save small collections of key-value pairs.
 
-Example for Java:
+Since Android 4.2 (API level 17) the `SharedPreferences` object can only be declared to be private (and not world-readable, i.e. accessible to all apps). However, since data stored in a `SharedPreferences` object is written to a plain-text XML file so its misuse can often lead to exposure of sensitive data.
 
-```java
-SharedPreferences sharedPref = getSharedPreferences("key", MODE_WORLD_READABLE);
-SharedPreferences.Editor editor = sharedPref.edit();
-editor.putString("username", "administrator");
-editor.putString("password", "supersecret");
-editor.commit();
-```
-
-Example for Kotlin:
+Consider the following example:
 
 ```kotlin
-var sharedPref = getSharedPreferences("key", Context.MODE_WORLD_READABLE)
+var sharedPref = getSharedPreferences("key", Context.MODE_PRIVATE)
 var editor = sharedPref.edit()
 editor.putString("username", "administrator")
 editor.putString("password", "supersecret")
@@ -74,14 +65,31 @@ Once the activity has been called, the file key.xml will be created with the pro
 </map>
 ```
 
-- `MODE_WORLD_READABLE` allows all applications to access and read the contents of `key.xml`.
+`MODE_PRIVATE` makes the file only accessible by the calling app. See ["Use SharedPreferences in private mode"](https://developer.android.com/privacy-and-security/security-best-practices#sharedpreferences).
 
-```bash
-root@hermes:/data/data/sg.vp.owasp_mobile.myfirstapp/shared_prefs # ls -la
--rw-rw-r-- u0_a118    170 2016-04-23 16:51 key.xml
-```
+> Other insecure modes exist, such as `MODE_WORLD_READABLE` and `MODE_WORLD_WRITEABLE`, but they have been deprecated since Android 4.2 (API level 17) and [removed in Android 7.0 (API Level 24)](https://developer.android.com/reference/android/os/Build.VERSION_CODES#N). Therefore, only apps running on an older OS version (`android:minSdkVersion` less than 17) will be affected. Otherwise, Android will throw a [SecurityException](https://developer.android.com/reference/java/lang/SecurityException). If an app needs to share private files with other apps, it is best to use a [FileProvider](https://developer.android.com/reference/androidx/core/content/FileProvider) with the [FLAG_GRANT_READ_URI_PERMISSION](https://developer.android.com/reference/android/content/Intent#FLAG_GRANT_READ_URI_PERMISSION). See [Sharing Files](https://developer.android.com/training/secure-file-sharing) for more details.
 
-> Please note that `MODE_WORLD_READABLE` and `MODE_WORLD_WRITEABLE` were deprecated starting on API level 17. Although newer devices may not be affected by this, applications compiled with an `android:targetSdkVersion` value less than 17 may be affected if they run on an OS version that was released before Android 4.2 (API level 17).
+You might also use [`EncryptedSharedPreferences`](https://developer.android.com/reference/androidx/security/crypto/EncryptedSharedPreferences), which is wrapper of `SharedPreferences` that automatically encrypts all data stored to the shared preferences.
+
+```kotlin
+var masterKey: MasterKey? = null
+masterKey = Builder(this)
+    .setKeyScheme(MasterKey.KeyScheme.AES256_GCM)
+    .build()
+
+val sharedPreferences: SharedPreferences = EncryptedSharedPreferences.create(
+    this,
+    "secret_shared_prefs",
+    masterKey,
+    EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV,
+    EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM
+)
+
+val editor = sharedPreferences.edit()
+editor.putString("username", "administrator")
+editor.putString("password", "supersecret")
+editor.commit()
+```
 
 ### Databases
 

tests/android/MASVS-STORAGE/MASTG-TEST-0001.md

@@ -9,6 +9,8 @@ title: Testing Local Storage for Sensitive Data
 masvs_v1_levels:
 - L1
 - L2
+status: deprecated
+covered_by: [MASTG-TEST-0207, MASTG-TEST-0200]
 ---
 
 ## Overview