Application layer protocols can represent the same data in a variety of ways. The Firepower System provides application layer protocol decoders that normalize specific types of packet data into formats that the intrusion rules engine can analyze. Normalizing application-layer protocol encodings allows the rules engine to effectively apply the same content-related rules to packets whose data is represented differently and obtain meaningful results.
Reference:
FirePower uses many preprocessors, including DNS, FTP/Telnet, SIP, SSL, SMTP, SSH preprocessors.

The call to API of "https://api.amp.cisco.com/v1/computers" allows us to fetch list of computers across your organization that Advanced Malware Protection (AMP) sees.
Reference:
2Fcomputers&api_host=api.apjc.amp.cisco.com&api_resource=Computer&api_version=v1

SQL injection usually occurs when you ask a user for input, like their username/userid, but the user gives ("injects") you an SQL statement that you will unknowingly run on your database. For example:
Look at the following example, which creates a SELECT statement by adding a variable (txtUserId) to a select string. The variable is fetched from user input (getRequestString):
txtUserId = getRequestString("UserId");
txtSQL = "SELECT * FROM Users WHERE UserId = " + txtUserId;
If user enter something like this: "100 OR 1=1" then the SzQL statement will look like this:
SELECT * FROM Users WHERE UserId = 100 OR 1=1;
The SQL above is valid and will return ALL rows from the "Users" table, since OR 1=1 is always TRUE. A hacker might get access to all the user names and passwords in this database.