Garbage characters being saved in Payment method input text fields

Question

I was playing with one store and noticed some weird behavior. When I tried to edit the Payment Methods title, it saved as garbage characters. Refer the snapshot.

Garbage characters was saved not only in titles but all the input text fields with some values.

Answer 1

This could also be related to this bug Magento - Error Saving Configuration - Encrypting The bug is fixed in app/code/core/Mage/Adminhtml/Model/Config/Data.php

    /**
     * Get field backend model
     */
    unset( $backendClass ); // Add this line
    if (isset($fieldConfig->backend_model)) {
        $backendClass = $fieldConfig->backend_model;
    }
    if (!isset($backendClass)) {
        $backendClass = 'core/config_data';
    }

Answer 2

I think you need to go through the installed extensions' system.xml files to check if any of them extend payment/ccsave/title and override the default back-end model by adding:

<backend_model>adminhtml/system_config_backend_encrypted</backend_model>

Additionally you can check if this class Mage_Adminhtml_Model_Config_Data is unmodified. The below code sets the default

/**
 * Get field backend model
 */
$backendClass = $fieldConfig->backend_model;
if (!$backendClass) {
    $backendClass = 'core/config_data';
}

The same class also dispatches this event model_config_data_save_before which could be used by someone to tinker with the config data.