Sunday, May 18, 2014

Dirty PowerShell WebServer

I was recently asked why there wasn't a PowerShell entry in this great list of web-server one-liners. Of course it is possible, but not as easy as with other scripting languages. Web-servers are dangerous in the wrong hands, but testers use them all the time (not always safely). I have seen people upload utilities like Mongoose to accomplish serving static files, but it can  be accomplished with PowerShell and the .Net httplistener class. The goal of the one-liners was to serve static files from the present working directory on port 8000. Since we know the goal is to have a small and dirty script, we can skip error-handling and use aliases:

So that wasn't painful, but not too helpful. How did we get here? Lets pipe the created object to Get-Member and explore the relevant properties and methods.

Now that we can put together a basic usage of the httplistener object, lets explore some of the properties of the request. Specifically, we need to know what part of the request we can use to find the name of the file. We can use the debugger that comes with the ISE to catch our loop and use the console to enumerate each of the properties until we find the one we want:

Now that we have everything put together, we just need roll it into a one-liner and encode it:

Finally, we have our encoded one-liner which will statically serve files from the present working directory.

We will need to have admin rights to grab a port, but otherwise it is pretty handy.

Thanks for reading about the basics of the httplistener class, maybe you will find it useful.


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