Intra-EPG Isolation is an option to prevent physical or virtual endpoint devices that are in the same base EPG or microsegmented (uSeg) EPG from communicating with each other. By default, endpoint devices included in the same EPG are allowed to communicate with one another.

Cross site scripting (also known as XSS) occurs when a web application gathers malicious data from a user. The data is usually gathered in the form of a hyperlink which contains malicious content within it. The user will most likely click on this link from another website, instant message, or simply just reading a web board or email message.
Usually the attacker will encode the malicious portion of the link to the site in HEX (or other encoding methods) so the request is less suspicious looking to the user when clicked on.
For example the code below is written in hex: <a
href=javascript:alert&#
x28'XSS')>Click Here</a>
is equivalent to:
<a href=javascript:alert('XSS')>Click Here</a>
Note: In the format "&#xhhhh", hhhh is the code point in hexadecimal form.

The Firepower System uses network discovery and identity policies to collect host, application, and user data for traffic on your network. You can use certain types of discovery and identity data to build a comprehensive map of your network assets, perform forensic analysis, behavioral profiling, access control, and mitigate and respond to the vulnerabilities and exploits to which your organization is susceptible.
You can configure your network discovery policy to perform host and application detection.

If sysopt permit-vpn is not enabled then an access control policy must be created to allow the VPN traffic through the FTD device. If sysopt permit-vpn is enabled skip creating an access control policy. Reference: https://www.cisco.com/c/en/us/support/docs/security-vpn/ipsec-negotiation-ike-protocols/215470- site-to-site-vpn-configuration-on-ftd-ma.html