Interswitch is the leading ATM/POS network in Nigeria and is the power behind the debit/ATM cards issued by over 20 banks in Nigeria including Guaranty Trust Bank, UBA, Intercontinental Bank, First Bank, Union Bank, Ecobank etc.
To make payment online using an Interswitch card, all that is needed is the card number and PIN. This makes the card users even more vulnerable. Some scammers have been sending out fake emails and text messages, requesting card users to enter their card number and PIN usually under the disguise of updating their profile for security reasons. See an example of such phoney emails, which I got just this morning:
We at Interswitch Nigeria, are upgrading to serve our customers for a better and secure online service, against any fraudulent activities. Due to this recent upgrade, some of our data was lost so you are requested to update your account information by following the reference below.
Regards Copyright © 2007 Interswitch Nigeria Ltd. All rights reserved.
I crossed-out the URL above. Though the domain name in that URL is really that of Interswitch Nigeria, the link in the email leads to some scammy page so do not click the links in any such emails or respond to such text messages. If in doubt, contact the bank that issued your card for any queries.