AWS EC2 & Quick FTP Server

 Sometimes you just need to transfer some files back and forth over FTP and want something quick and easy. There are a couple of caveats to getting a one-liner-ish FTP server running in AWS EC2 or lightsail:

1. Additional ports must be opened. Lightsail by default opens 80 & 22. You'll have to also open 21 & 8000-9000 for the following to work. Or you know, open it all because yolo.
2. File transfers must happen in FTP passive mode. This is the default mode of pftp and lftp on Kali. If you use the basic ftp binary, you have to issue the "passive" command after you connect.

Here are the commands to quick-start:

Google/AWS/Azure IP Ranges

Google Cloud, Amazon AWS, and Microsoft Azure publish their IP ranges for their cloud platforms.

Amazon:
https://ip-ranges.amazonaws.com/ip-ranges.json
one-liner:
     curl https://ip-ranges.amazonaws.com/ip-ranges.json | grep 'ip_prefix' | cut -d '"' -f 4

Microsoft Azure:
https://www.microsoft.com/en-gb/download/details.aspx?id=41653
one-liner:
     cat PublicIPs_20190401.xml | grep 'IpRange Subnet='| cut -d '"' -f2

Google Cloud:
DNS txt records for: _cloud-netblocks.googleusercontent.com
one-liner:
     for netblock in $(dig txt _cloud-netblocks.googleusercontent.com +short | tr " " "\n" | grep include | cut -f 2 -d :); do dig txt +short $netblock; done | tr " " "\n" | grep ip4: | cut -d ':' -f2