Stuck on an issue?

Lightrun Answers was designed to reduce the constant googling that comes with debugging 3rd party libraries. It collects links to all the places you might be looking at while hunting down a tough bug.

And, if you’re still stuck at the end, we’re happy to hop on a call to see how we can help out.

Connection resets after uploading a file linux

See original GitHub issue

Bug Description

After uploading a file with pwncat on some machines, trying to access the same shell will result in the connection being reset. Interesting this doesn’t happen when I try to establish a reverse shell in my local machine but fails on remote machines.

pwncat version

Using pwncat in docker.
$ pwncat --version
0.4.2

Target System (aka “victim”)

https://tryhackme.com/room/toc2

Steps to Reproduce

Steps to reproduce the behavior:

Obtain a shell, then CTRL+D
Upload linpeas.sh
CTRL+D again to enter the remote session.

Expected Behavior

Able to access session after successfully uploading a file

(remote) frank@toc:/home/frank$ 
(local) pwncat$ upload /tools/peas/linPEAS/linpeas.sh
./linpeas.sh ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 100.0% • 342.9/342.9 KB • ? • 0:00:00
[08:46:04] uploaded 334.83KiB in 3.25 seconds                                                                                                                                                                                     upload.py:85
(local) pwncat$                                                                                                                                                                                                                               

[08:46:25] warning: 10.10.224.225:56778: connection reset                                                                                                                                                                       manager.py:496
(local) pwncat$

Issue Analytics

State:
Created 2 years ago
Comments:10 (10 by maintainers)

Top GitHub Comments

1reaction

Mitul16commented, Jun 17, 2021

Yes, this is why the loop for sending C-d wasn’t a good method Thank you for your time explaining all of this 😀

1reaction

calebstewartcommented, Jun 17, 2021

The internals of termios settings and TTY/PTYs gets very confusing and a lot of it is so closely coupled with kernel implementations and archaic standards that understanding it’s interaction is difficult. That added to the fact that most people don’t use these settings makes finding information on what the “correct” or “standard compliant” API is difficult. I’ve read the termios man page more times than I’d like to admit trying to figure out how all this works. Lol