Full Disclosure mailing list archives
Strange interactions between tunnelling and SMB under the proprietary Microsoft Windows environment
From: schaefer () alphanet ch (Marc SCHAEFER)
Date: Thu, 30 Mar 2006 07:52:10 +0200
Hi, first, a disclaimer: I don't really need the proprietary Microsoft Windows environment for my work. It happens that, for interoperability's sake, I sometimes install free (libre) software on this proprietary environment on customer systems. It's always quite painful, has strange implications, and is always quite difficult to debug. But well, some people apparently still need it. After that, the issue I saw, which I currently cannot understand: I installed the libre software OpenVPN including the TAP driver on the proprietary Microsoft Windows environment. I did set up a encrypted tunnel between two machines on the same Ethernet subnet (this is probably important). Testing pings and telnet on the remote tunnel address (e.g. 192.168.1.2) and capturing data with the libre software Ethereal on the real Ethernet interface did show me that the flow of data was correctly routed through the tunnel. However, accessing \\192.168.1.2\c$ did go through the Ethernet interface, and *not the tunnel*, and strangely half-using the private addresses! I wonder if there is some NetBEUI/NetBIOS/whatever interaction which kind-of `resolves' the private IP address as a host name. Thus probably as long as noone replies NetBEUI/NetBIOS it should work ... but could be exploitable, isn't it ? The obvious solution could be to completely disable this resolution, or maybe use a real DNS name for the private addresses of the tunnel. After all NetBEUI/NetBIOS predates the standard IP networking support in the proprietary Microsoft Windows environment and could be considered obsolete today (if using a WINS server or DNS resolution). But it is still activated by default. Looking at the routing tables through NETSTAT.EXE is ... well ... strange. No interface, strange routes, it's a bit difficult to really understand how routing works on this proprietary plateform. Has someone also experienced this, or was it some strange local pecularity ? _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
Current thread:
- Strange interactions between tunnelling and SMB under the proprietary Microsoft Windows environment Marc SCHAEFER (Mar 29)