Re: [Full-disclosure] iDefense Security Advisory 07.09.07: WinPcap NPF.SYS Local Privilege Escalation Vulnerability

iDefense Labs wrote:
WinPcap NPF.SYS Local Privilege Escalation Vulnerability

iDefense Security Advisory 07.09.07
http://labs.idefense.com/intelligence/vulnerabilities/
Jul 09, 2007

I. BACKGROUND

WinPcap is a software package that facilitates real-time link-level
network access for Windows-based operating systems. It is used by a
wide range of open-source projects including Wireshark. More
information is available at the project web site at the URL shown
below.

http://www.winpcap.org/

II. DESCRIPTION

Local exploitation of an input validation vulnerability within the
NPF.SYS device driver of WinPcap allows attackers to execute arbitrary
code in kernel context.

The vulnerability specifically exists due to insufficient input
validation when handling the Interrupt Request Packet (Irp) parameters
passed to IOCTL 9031 (BIOCGSTATS). By passing carefully chosen
parameters to this IOCTL, an attacker can overwrite arbitrary kernel
memory.

III. ANALYSIS

Exploitation allows attackers to execute arbitrary code in kernel
context.

The vulnerable device driver is loaded when WinPcap is initialized. This
driver can be set to load on start-up depending on a choice made at
installation time. This is not the default setting.

In a default installation, the device driver is not loaded until an
Administrator utilizes a WinPcap dependent application. Once they do,
it will become accessible to normal users as well. When a program using
this driver exists, it is not unloaded. Attackers will continue to have
access until the driver is manually unloaded.
Nobody seemed to care about my patch for custom security on the capture
device:

<http://www.winpcap.org/pipermail/winpcap-bugs/2005-June/000029.html>

In other news, Microsoft just released Network Monitor 3.1:

<http://www.microsoft.com/downloads/details.aspx?familyid=18b1d59d-f4d8-4213-8d17-2f6dde7d7aac>

(I'm extremely impressed by the improvements on 2.x, BTW)

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