CI4MS Vulnerable to Arbitrary Database Table Drop via Theme deleteProcess

Summary

The deleteProcess() action accepts a POST parameter tables[] containing arbitrary table names. These are passed directly to $forge->dropTable() without validating that the tables belong to the theme being deleted.

The deleteConfirm view correctly populates tables[] from the theme's own migration files, but the server-side deleteProcess does not verify the received values against those files. An authenticated admin can craft a POST request with arbitrary table names and drop any table in the database.

This is a real bug even within the admin trust model: the action should be scoped to the theme's own tables. The permission grants delete this theme's data", not "drop any table".

Details

Location

modules/Theme/Controllers/Theme.php :: deleteProcess() ~line 147

Vulnerable Code

public function deleteProcess(string $slug)
{
    $themeName = $slug;
    $activeTheme = setting('App.siteTheme');
    if ($activeTheme === $themeName) {
        return redirect()->route('templateSettings')...;
    }

    $tablesToDrop = $this->request->getPost('tables');  // ← user-supplied, unvalidated
    if (!empty($tablesToDrop) && is_array($tablesToDrop)) {
        $forge = \Config\Database::forge();
        $db    = \Config\Database::connect();
        foreach ($tablesToDrop as $table) {
            if ($db->tableExists($table)) {
                $forge->dropTable($table, true);  // ← no whitelist check
            }
        }
    }

PoC

1. Authenticate to the backend (any user with theme.delete permission)
2. POST to /backend/themes/delete-process/<any_non_active_theme_slug>
3. Include tables[]=<any_table> in POST body
4. The named tables are dropped without validation

Impact

• Dropped ci4ms_blog (confirmed in test)
• Dropped ci4ms_users + ci4ms_auth_identities simultaneously — disables all authentication (confirmed)
• Any table in the database can be targeted

Additional note

Quick note on the design intent for deleteProcess — I noticed delete_confirm.php scopes the checkboxes to the theme's own migration files, and the CHANGELOG confirms the selective deletion was intentional (admins can choose which tables to keep). The server-side deleteProcess already has all the information it needs to validate the input — deleteConfirm derives the valid table set from the migration files, deleteProcess just needs to do the same before acting on the POST. Happy to clarify if useful.