Outlook Web is the browser-based version of Microsoft Outlook used to read, send, and manage email without installing a desktop client. Because it runs in a web browser, it is often a primary gateway to corporate mail for remote and managed devices.
In cyber security, Outlook Web matters because email is a common attack channel. Threat actors try to deliver phishing links, malicious attachments, or social-engineering prompts through inboxes, while defenders use Outlook Web policies to filter content before it reaches users. Attachment blocking, link protection, and conditional access can all be enforced here. In the context of software delivery, blocking file types such as MSIX in Outlook Web reduces the chance that installable packages arrive by email and exposes fewer opportunities for users to launch risky content from the inbox.