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. If the option to allow normal user access was chosen at installation time, attackers will always have access to this device driver. Consequently, a local attacker without administrator privileges would have access to sniff, as well as exploit this vulnerability. IV. DETECTION iDefense has confirmed the existence of this vulnerability in version 4.0 of WinPcap as included in Wireshark 0.99.5. The version of NPF.SYS tested was 4.0.0.755. Older versions are suspected to be vulnerable. V. WORKAROUND iDefense is currently unaware of any effective workaround for this issue. VI. VENDOR RESPONSE The WinPcap Team has addressed this vulnerability by releasing version 4.0.1 of the WinPcap software. For more information, see the following URL. http://www.winpcap.org/misc/changelog.htm VII. CVE INFORMATION A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not been assigned yet. VIII. DISCLOSURE TIMELINE 05/16/2007 Initial vendor notification 05/16/2007 Initial vendor response 07/09/2007 Coordinated public disclosure IX. CREDIT This vulnerability was reported to iDefense by Mario Ballano from 48bits.com. Get paid for vulnerability research http://labs.idefense.com/methodology/vulnerability/vcp.php Free tools, research and upcoming events http://labs.idefense.com/ X. LEGAL NOTICES Copyright © 2007 iDefense, Inc. Permission is granted for the redistribution of this alert electronically. It may not be edited in any way without the express written consent of iDefense. If you wish to reprint the whole or any part of this alert in any other medium other than electronically, please e-mail customerservice@private for permission. Disclaimer: The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information.
This archive was generated by hypermail 2.1.3 : Tue Jul 10 2007 - 17:33:03 PDT