Re: file transfer over outbound port 80?

["Dana Epp" <dana () vulscan com>]

I actually do this right now. I simply set my ssh daemon on port 80, and use
scp to covertly bypass most standard firewalls. Unless they do payload
inspection, you can normally pierce the firewall fine in this manner.

ie: scp -P 80 user () corp sshd-server com:/get/some/file/ .

Short of that, you could probably simply redirect a HTTPS stream on port 80,
and use some sort of auth to your main server and upload/download via that
protocol. A lot more work... and not as flexible as the SSH method.

One thing to consider is that some firewalls may be using a transparent
proxy, and you might only be getting through by that proxy. If this is the
case, there is a good chance these methods will not work for you.

---
Regards,
Dana M. Epp

----- Original Message ----- 
From: "abe vigoda" <ells_on_zone () yahoo com>
To: <security-basics () securityfocus com>
Sent: Thursday, August 07, 2003 8:50 AM
Subject: file transfer over outbound port 80?


> Here's our issue:
>
> We often have engineers on site at customer locations
> where we need to drop off or pick up files from a
> public file server. Currently we are using ftp for
> this purpose however ftp outbound is being blocked by
> more and more of our customers and only port 80 is
> open.
>
> My question is really what is the best way to work
> around this problem? Is there a web-based application
> out there that only does this simple job over port 80?
> I have never seen this addressed here but I know we're
> not the first ones to run into this issue.
>
>
> Thanks all for any help.
>
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