The best recommendation to remediate this vulnerability is to use parameterized queries in the web application. Parameterized queries are a way of preventing SQL injection attacks by separating the SQL statements from the user input. This way, the user input is treated as a literal value and not as part of the SQL statement. For example, instead of using x' OR role LIKE '%admin%, the user input would be passed as a parameter to a prepared statement that would check if it matches any value in the database.

Explanation
Nmap is a tool that can perform network scanning and enumeration by sending packets to hosts and analyzing their responses. The command Nmap -p 445 -n -T4 --open 172.21.0.0/16 would scan for SMB port 445 over a
/16 network with the following options:
-p 445 specifies the port number to scan.
-n disables DNS resolution, which can speed up the scan by avoiding unnecessary queries.
-T4 sets the timing template to aggressive, which increases the speed of the scan by sending packets faster and waiting less for responses.
-open only shows hosts that have open ports, which can reduce the output and focus on relevant results.
The other commands are not optimal for scanning SMB port 445 over a /16 network when stealth is not a concern and the task is time sensitive.

Explanation
A Web Application Firewall (WAF) is designed to monitor, filter or block traffic to a web application. A WAF will monitor incoming and outgoing traffic from a web application and is often used to protect web servers from attacks such as SQL Injection, Cross-Site Scripting (XSS), and other forms of attacks. If a WAF detects an attack, it will often reset the TCP connection, causing the connection to be terminated. As a result, a penetration tester may see TCP resets when a WAF is present. Therefore, the most likely reason for the TCP resets returning from the web server is that the web server is using a WAF.

The file .scripts/daily_log_backup.sh has permissions set to 777, meaning that anyone can read, write, or execute the file. Since it's owned by the root user and the penetration tester has access to the system with a non-privileged account, this could be a potential avenue for privilege escalation. In a penetration test, after finding such a file, the tester would likely want to explore it and see if it can be leveraged to gain higher privileges. This is often done by inserting malicious code or commands into the script if it's being executed with higher privileges, such as root in this case.