a web shell is a web security threat, which is a web-based implementation of the shell concept. a web shell is able to be uploaded to a web server to allow remote access to the web server, such as the web server's file system. a web shell is unique in that it enables users to access a web server by way of a web browser that acts like a command-line interface.<br> a user can access a remote computer via the world wide web using a web browser on any type of system, whether it's a desktop computer or a mobile phone with a web browser, and perform tasks on the remote system. no command-line environment is required on either the host or the client. a web shell is often considered a remote access trojan.