zdns VS masscan

Should you be in the mood to script doing a lot of lookups, you can feed dig a file of domain names (one per line) to look up (dig -f names.txt > dig.out). But if you're heading off in that direction you probably want https://github.com/zmap/zdns (and carefully read the "Running ZDNS" section of README.md before you make your recursive resolver sick).

It's a nice dream of "owning" the attackers but it doesn't have a real security value.

[1] https://github.com/robertdavidgraham/masscan

A lot of these seem to use zmap (https://github.com/zmap/zmap) or massscan (https://github.com/robertdavidgraham/masscan) for the initial scan.

Often with default parameters such as zmap setting ip id to 54321, having tcp initial window at 65535, having no SACK bit set and masscan with no SACK bit either, tcp initial window at 1024, tcp maximum segment size 1460 (which is strange to put below initial window size!), (older versions having fixed src port 61000 or 60000 from documentation examples and no MSS set), all of which are extremly uncommon in legitimate traffic and thus easily identified.

Even those so called "legitimate" scanners (emphasis on the "") seem to use these tools with little or no extra configuration.

Can I get banned for mass scanning with https://github.com/robertdavidgraham/masscan or does it slow down any other vms from other persons?

Nope, this doesn't work any more. Shodan checks all ports (so any attackers using data from Shodan already know which ports you have open), and tools like masscan (https://github.com/robertdavidgraham/masscan) let you portscan the entire IPv4 address space in less than 10 minutes.

https://github.com/LogoiLab/mcsl https://github.com/robertdavidgraham/masscan

Changing the default port does nothing for security. It only prevents some basic brute force or default password scripts. Anyone is able to scan for it in no time anyway (https://github.com/robertdavidgraham/masscan).

But it should blow away the far-too-common belief that no-one's after you because you're not interesting enough. IPv4 is smaller than we think. It is not difficult to scan the entire ipv4 space in minutes. And every single one of those is going to knock your door on the way past.

I'm not sure about the article, but the blazingly-fast IP scanner sounds a lot like Masscan. It can scan the entire Internet in 5 minutes and has received a lot of press: https://github.com/robertdavidgraham/masscan . https://rushter.com/blog/how-masscan-works/ is one of many articles about it.

Here's an except from the masscan docs: