Mubix (Rob Fuller/Room362) has just released a Meterpreter script allowing an active session to download and initiate the the recent Cygwin bundled Metasploit. Get to the script and binary downloads via his blog post.

I haven't had a chance to fully play with it yet, but it opens up some interesting possibilities and should definitely come in handy.

This is looking like another promising feature in the framework. Can't wait for CG to do a blog entry on Carnal0wnage about it -hints- 

Chris, good point. I hadn't look at using the script in live environments yet, just playing around with my home lab.

AV coverage appears pretty weak so far, VirusTotal results for the 5MB mini binary currently show 27% flagging as malicious. Coverage is also fairly random, some of the big boys flag it (Kaspersky, MS, Trend) whilst other large AV players treat it as benign (Symantec, McAfee, AVG). Of course heuristic and active scanning may trip other flags as you delve deeper.

Not sure how this will change in the future as more AV firms get to grips with the release, your milage may vary.....

Couldnt we obfuscate the binary(ies)? using garbage insertion, variable renaming, code reordering, encapsulating/encrypting code or data, or branching functions? i'd be a lot of work, but virus writers do it.... just an idea...

i think that the problem occurs mostly when the mini msf exe is exploded on the other side.  at least for me, the AV picks up random rb files as potentially dangerous files.  it basically appears to know that something isn't right, but doesn't know exactly what.   this is likely the heuristics engine kicking in. 

i think that if you exploit a linux box and upload a linux version of msf, you should be golden.   on a windows box with a/v, it really depends on the a/v.   i think that the way to go is an agent based approach like Core does.  i believe their agents sits entirely in RAM and just listens for and passes commands.

Actually I talked to Rob and the removal of certain exploits brings down the virus detection significantly. This in conjunction with flipping some bits on the exc almost makes it perfect.