I am trying to use masscan to scan ports of multiple IP addresses. How to provide list of IP addresses in the input of command ? So far I have used the following command. But there is only one IP address is possible to check.
System state can change, so you have to take that into consideration. I would trust the accuracy of nmap/zenmap over masscan. Masscan is known for fast scans, but nmap has better accuracy base on my experience. Itβs good that you are using multiple tools, which is always a good idea. Your syntax looks good and I after you find your open ports, you could scan with nmap using -sV to get version information and -sC to run the default NSE scripts and these two should help you find more useful information.
Dirb and Dirbuster are good, but I would use OWASP Zap or Burp Suite for for forced browsing and content discovery.
This might be helpful for the 400 HTTP errors that you are getting, but I tend to lean toward the header being too long or the malformed header.
I would do a service scan with nmap (-sV) and NSE default scripts (-sC) to see if you can get finger print the services to enumerate the particular type of software and version running on those ports. You can get some of that info using Burp or ZAP.
You could also run curl -I to get HTTP header info, which sometimes reveals the web server or web app server version. I also like running Nikto, it can reveal version info, default creds and vulnerabilities. I have had pretty good luck with Nikto.
You can run the HTTP methods NSE script to see if the target has any HTTP methods that could be exploited; nmap --script http-methods