phpMyFAQ has Authenticated SQL Injection in Configuration Update Functionality

Summary

An authenticated SQL injection vulnerability in the main configuration update functionality of phpMyFAQ (v4.0.13 and prior) allows a privileged user with 'Configuration Edit' permissions to execute arbitrary SQL commands. Successful exploitation can lead to a full compromise of the database, including reading, modifying, or deleting all data, as well as potential remote code execution depending on the database configuration.

Details

The vulnerability exists in the save method within the src/phpMyFAQ/Controller/Administration/ConfigurationTabController.php controller. This method handles the saving of application-wide configuration settings. It retrieves all submitted form data as an associative array via $request->get('edit').

The core of the issue is that while the values of this array are processed, the keys are trusted implicitly and are not sanitized or validated.

File: src/phpMyFAQ/Controller/Administration/ConfigurationTabController.php

// ...
public function save(Request $request): JsonResponse
{
    $this->userHasPermission(PermissionType::CONFIGURATION_EDIT);

    $configurationData = $request->get('edit');
    // ...
    
    foreach ($configurationData as $key => $value) {
        // The key from the user input is used to build the $newConfigValues array.
        $newConfigValues[$key] = (string) $value;
        // ...
    }

    // ...
    // The array, containing user-controlled keys, is passed to the model.
    $this->configuration->update($newConfigValues);

    return $this->json(['success' => Translation::get('ad_config_saved')], Response::HTTP_OK);
}

The $newConfigValues array, which contains user-controlled keys, is then passed to the update method in the src/phpMyFAQ/Configuration.php model. Here, the key ($name) is directly concatenated into a raw SQL query string.

File: src/phpMyFAQ/Configuration.php

public function update(array $newConfigs): bool
{
    // ...
    foreach ($newConfigs as $name => $value) {
        if ($name != 'main.phpMyFAQToken' && !in_array($name, $runtimeConfigs)) {
            // VULNERABLE CODE: The array key '$name' is not escaped and is directly
            // concatenated into the SQL query string. The value is escaped, but not the name.
            $update = sprintf(
                "UPDATE %s%s SET config_value = '%s' WHERE config_name = '%s'",
                Database::getTablePrefix(),
                $this->tableName,
                $this->getDb()->escape(trim($value)),
                $name
            );

            $this->getDb()->query($update);
            // ...
        }
    }

    return true;
}