Application level firewalls are the best control to prevent the transfer of files to external parties through instant messaging (IM) applications, because they can inspect and filter network traffic based on application-specific protocols and commands, such as IM file transfer commands. Application level firewalls can block or allow IM file transfers based on predefined rules or policies. File level encryption, file transfer protocol (FTP), and instant messaging policy are not effective controls to prevent IM file transfers, because they do not restrict or monitor IM network traffic. References: CISA Review Manual (Digital Version), Chapter 5, Section 5.4.1

The best evidence that an organization's IT strategy is aligned to its business objectives is that the IT strategy is approved by executive management. This implies that the IT strategy has been reviewed and validated by the senior leaders of the organization, who are responsible for setting and overseeing the business objectives. The IT strategy may be modified in response to organizational change, based on IT operational best practices, or have significant impact on the business strategy, but these are not sufficient indicators of alignment without executive approval. References: CISA Review Manual (Digital Version)1, Chapter 1, Section 1.2.1