A.15 Control section

I’m assuming that by Y2005 and Y.2013 you are referring to versions 2005 and 2013 of ISO 27001.

Considering that, there is no official explanation for this change, but most probably the change was made to make the application of the control clearer.

ISO generally uses the term “third party” for an entity that is independent of the organization, like customers, suppliers, business partners, government, etc.

Since the controls from ISO 27001 Annex A are related to suppliers, it makes more sense to change the section name to reflect this situation.

This article will provide you a further explanation about supplier security management:

- 6-step process for handling supplier security according to ISO 27001 https://advisera.com/27001academy/blog/2014/06/30/6-step-process-for-handling-supplier-security-according-to-iso-27001/