what you don't know can hurt you

Microsoft DHCP INFORM Configuration Overwrite

Microsoft DHCP INFORM Configuration Overwrite
Posted May 30, 2014
Authored by laurent gaffie

A vulnerability in Windows DHCP was found on Windows OS versions ranging from Windows 2000 through to Windows server 2003. This vulnerability allows an attacker to remotely overwrite DNS, Gateway, IP Addresses, routing, WINS server, WPAD, and server configuration with no user interaction. Successful exploitation of this issue will result in a remote network configuration overwrite. Microsoft acknowledged the issue but has indicated no plans to publish a patch to resolve it.

tags | advisory, remote
systems | windows, 2k
MD5 | 535d32799e8d5c79bd314ee2a3a71e9b

Microsoft DHCP INFORM Configuration Overwrite

Change Mirror Download
Title:           Microsoft DHCP INFORM Configuration Overwrite
Version: 1.0
Issue type: Protocol Security Flaw
Affected vendor: Microsoft
Release date: 28/05/2014
Discovered by: Laurent GaffiƩ
Advisory by: Laurent GaffiƩ
Issue status: Patch not available
===============================================================================

Summary
-------

A vulnerability in Windows DHCP (http://www.ietf.org/rfc/rfc2131.txt) was
found on Windows OS versions
ranging from Windows 2000 through to Windows server 2003. This
vulnerability allows an attacker to remotely
overwrite DNS, Gateway, IP Addresses, routing, WINS server, WPAD, and
server configuration with no user
interaction. Successful exploitation of this issue will result in a remote
network configuration
overwrite. Microsoft acknowledged the issue but has indicated no plans to
publish a patch to resolve it.


Technical details
-----------------

Windows 2003/XP machines are sending periodic DHCP INFORM requests and are
not checking if the DHCP INFORM answer (DHCP ACK) is from the registered
DHCP server/relay-server. Any local system may respond to these requests
and overwrite a Windows 2003/XP network configuration by sending a properly
formatted unicast reply.

Impact
------

Successful attempts will overwrite DNS, WPAD, WINS, gateway, and/or routing
settings on the target system.

Affected products
-----------------

Windows:
- 2000
- XP
- 2003

Proof of concept
----------------
The DHCP.py utility found within the Responder toolkit can be used to
exploit this vulnerability.

git clone https://github.com/Spiderlabs/Responder

Solution
--------
Set a DWORD registry key "UseInform" to "0" in each subfolder found in
HKLM\SYSTEM\CCS\Services\TCP\Interfaces\

Response timeline
-----------------
* 18/04/2014 - Vendor notified.
* 18/04/2014 - Vendor acknowledges the advisory ( [MSRC]0050886 )
* 18/04/2014 - Suggested to vendor to run Responder on a A-D environment
while looking at the DHCP issue for education purposes. Since multiple
attempts were
made to have them be aware that any A-D environment by
default is vulnerable if Responder is running on the subnet. Also, MSRC was
asked what
code change made this DHCP INFORM issue different on Windows
Vista than Windows Server 2003.
* 21/04/2014 - MSRC answers with an automated response.
* 08/05/2014 - Request for a reply.
* 14/05/2014 - MSRC reply and refuses to share their view on the code
change, however they mention that 'The product team is investigating
whether the RFC for
a DHCPINFORM message is properly implemented'.
* 14/05/2014 - An email was sent to notify MSRC that no code change was
requested, but the logic behind it. Also, MSRC was asked if they were
successful with
Responder.
* 16/05/2014 - MSRC closes [MSRC]0050886 and doesn't provide any info on if
they were successful with Responder in their environment.


References
----------
* Responder: https://github.com/Spiderlabs/Responder
* http://g-laurent.blogspot.ca/
* https://twitter.com/PythonResponder
*
http://blog.spiderlabs.com/2014/02/responder-20-owning-windows-networks-part-3.html


Comments

RSS Feed Subscribe to this comment feed

No comments yet, be the first!

Login or Register to post a comment

File Archive:

April 2019

  • Su
  • Mo
  • Tu
  • We
  • Th
  • Fr
  • Sa
  • 1
    Apr 1st
    21 Files
  • 2
    Apr 2nd
    35 Files
  • 3
    Apr 3rd
    21 Files
  • 4
    Apr 4th
    16 Files
  • 5
    Apr 5th
    15 Files
  • 6
    Apr 6th
    1 Files
  • 7
    Apr 7th
    2 Files
  • 8
    Apr 8th
    23 Files
  • 9
    Apr 9th
    19 Files
  • 10
    Apr 10th
    15 Files
  • 11
    Apr 11th
    14 Files
  • 12
    Apr 12th
    11 Files
  • 13
    Apr 13th
    2 Files
  • 14
    Apr 14th
    5 Files
  • 15
    Apr 15th
    14 Files
  • 16
    Apr 16th
    19 Files
  • 17
    Apr 17th
    19 Files
  • 18
    Apr 18th
    8 Files
  • 19
    Apr 19th
    4 Files
  • 20
    Apr 20th
    5 Files
  • 21
    Apr 21st
    1 Files
  • 22
    Apr 22nd
    10 Files
  • 23
    Apr 23rd
    22 Files
  • 24
    Apr 24th
    11 Files
  • 25
    Apr 25th
    0 Files
  • 26
    Apr 26th
    0 Files
  • 27
    Apr 27th
    0 Files
  • 28
    Apr 28th
    0 Files
  • 29
    Apr 29th
    0 Files
  • 30
    Apr 30th
    0 Files

Top Authors In Last 30 Days

File Tags

Systems

packet storm

© 2019 Packet Storm. All rights reserved.

Services
Security Services
Hosting By
Rokasec
close