ISAE 3402 Overview
International Standard on Assurance Engagements (ISAE) No. 3402, Assurance Reports on Controls at a Service Organization, was issued in December 2009 by the International Auditing and Assurance Standards Board (IAASB), which is part of the International Federation of Accountants (IFAC). ISAE 3402 was developed to provide an international assurance standard for allowing public accountants to issue a report for use by user organizations and their auditors (user auditors) on the controls at a service organization that are likely to impact or be a part of the user organization’s system of internal control over financial reporting.
You can download a copy of ISAE 3402 from the IFAC website here.