I am playing with a Linux CTF server and came across a kind of reverse connection block. I uploaded a php webshell, gained control of www-data
user and tried to make a reverse shell.
Possible a UFW block at 1024~UP ports. In this server, I have SSH, FTP and HTTP services. Both SSH and FTP are ports above 1024. I have no ICMP communication between me and the machine, just loopback, even the Machine Gateway I cannot ping it.
So, if I can establish a HTTP session, I think which outbound port 80 is allowed, só I upload a new reverse shell php https://github.com/pentestmonkey/php-reverse-shell
(That's what I thought) and triggered from website, by click, by curl, I thought this way the machine source connection will be port 80, but even so, that does not work.
Does anyone have an idea? How I can bypass this block?