proxy.py VS ssh-mitm

[Not my project]

A very well features proxy server (Forward & Reverse + lots of other features).

https://github.com/abhinavsingh/proxy.py

The article gives a good summary of the quite complex landscape of concurrency in python. There's more to it, for example gil-free c-extensions, subprocesses and cross-machine (plus IPC) communication.

But I'm particularly bothered by the fact that many articles and tutorials look at concurrency as if it's only about factoring primes or writing a web server with many (perhaps even idempotent) parallel requests.

In reality, people will often want and need to combine multiple of these approaches, and then it gets VERY messy. I.e. try to combine a multiprocessing executor with multiple asyncio loops and boom you're in some very deep waters.

One project that does this (async loops inside multiple processes) is proxy.py - very enlightening to read its code base [1].

But I really, really wish python would do more to provide simple and robust abstractions for these kinds of tasks. My dream would be a robust actor system similar to erlang, but we'll probably never get that.

[1] https://github.com/abhinavsingh/proxy.py

Setup a VM with Hyper-V and restrict the internet access or disable it.(best way), or build yourself a proxy: https://github.com/abhinavsingh/proxy.py

See `proxy.py` examples for some inspiration :) https://github.com/abhinavsingh/proxy.py/tree/develop/examples

I wanted to share some insights into a security concern that echoes the Terrapin-Attack scenario, highlighting a similar vulnerability that has been observed in other tools.

Recently, I came across a Pull Request on GitHub for the SSH-MITM tool, which sheds light on a critical aspect of SSH protocol security, specifically regarding RFC 4253 during the KEXINIT process. The Pull Request, available at GitHub https://github.com/ssh-mitm/ssh-mitm/pull/163, describes the necessity of discarding certain packages during the KEXINIT phase to prevent issues with intercepted clients.

Moreover, a look into the GitHub Blame for SSH-MITM reveals that these crucial changes in the KEXINIT step were integrated into SSH-MITM about 1-2 years ago. You can see the specific changes at this link: https://github.com/ssh-mitm/ssh-mitm/blame/4fc3ef418847c35d17d0c427e2701b33a03c323c/sshmitm/workarounds/transport.py#L178-L188

An important note to add is that this information suggests that a similar form of attack, akin to the Terrapin-Attack, could potentially have been exploited for the last two years. This raises significant concerns about the historical vulnerability of systems to such attack techniques and emphasizes the importance of retroactive security analysis in addition to ongoing vigilance.

There is now an issue ticket in ssh-mitm to discuss the similarities between ssh-mitm and terrapin attack: https://github.com/ssh-mitm/ssh-mitm/issues/165

During some audits, it's likely that you find some ssh public keys laying around on some servers.

If you want to verify if this key is known by other services, but you don't have access to those services, this task might be hard.

SSH-MITM has an additional command, which allows to check if a public ssh key is known by GitHub, GitLab, and other code hosters. It's not limited to GitHub and other major platforms and even works with each service, which is accessible over SSH.

First you must install SSH-MITM. It's recommended to use the AppImage, because this works out of the box on most Linux machines.

$ wget https://github.com/ssh-mitm/ssh-mitm/releases/latest/download/ssh-mitm-x86_64.AppImage

SSH-MITM is a tool to audit ssh sessions and protocols, which uses SSH as the transport protocol: https://github.com/ssh-mitm/ssh-mitm

you can find the project on github: https://github.com/ssh-mitm/ssh-mitm

You should check the Revisionhistory of the Readme file first.. https://github.com/ssh-mitm/ssh-mitm/commit/564028af25c395528446fbb679c7392469d59bfd

The “customized wording” you’re seeing is “The LGPL”. It’s a different license from the GPL.

The history on the repo shows that the original license was GPL (June 2020), the author changed the license to LGPL (December 2022), and now they’re changing it to GPL again. https://github.com/ssh-mitm/ssh-mitm/commits/master/LICENSE