eEye Research - http://research.eeye.com Workstation Service NetpManageIPCConnect Buffer Overflow Release Date: November 14, 2006 Date Reported: July 25, 2006 Severity: High (Remote Code Execution) Vendor: Microsoft Systems Affected: Windows 2000 (Remote Code Execution) Windows XP SP1 (Local Privilege Escalation) Overview: A flaw exists in a default Windows component called the "Workstation Service" that when exploited allows for remote code execution in SYSTEM context, allowing an attacker to take complete control of affected systems. Technical Details: In the Workstation Service module called wkssvc.dll, the NetpManageIPCConnect function has a call to "swprintf" with an unchecked buffer. The input buffer is controllable by the remote attacker. .text:76781D67 mov edi, [ebp+arg_0] ... .text:76781D90 lea eax, [ebp+var_2CC] ... .text:76781DA0 push edi .text:76781DA1 push offset "%ws\\IPC$" .text:76781DA6 push eax .text:76781DA7 call ds:swprintf This function is called by NetpJoinDomain, which is eventually called by the NetrJoinDomain2 function, which is exposed through RPC. The IDL for NetrJoinDomain2 looks like this: long _NetrJoinDomain2@28 ( [in][unique][string] wchar_t * arg_1, [in][string] wchar_t * arg_2, [in][unique][string] wchar_t * arg_3, [in][unique][string] wchar_t * arg_4, [in][unique] struct_C * arg_5, [in] long arg_6 ); arg_2 will contain string with format like <Domain name>+"\"+<Hostname>. <Hostname> will be passed as NetpManageIPCConnect's first argument. The variable is under the attacker's control and is passed to swprintf, which causes a stack-based buffer overflow. For this vulnerable code to be reached, we must provide a valid and live <Domain name> as a part of the string. We can set up a fake domain server anywhere reachable from the vulnerable machine on the Internet. P.S. If you despise Birkenstocks, are not afraid of your Tequila, and are well versed in reverse engineering, bug finding, or are looking to learn, we are hiring both junior and senior security researchers. Send your resume (blathering of college course work, degrees, and past experience we don't care about) or more importantly a description of why you would be a good researcher to skunkworks@xxxxxxxxx Credit: Discovery: JeongWook Matt Oh Additional Research: Derek Soeder Related Links: Retina Network Security Scanner - Free Trial Blink Endpoint Vulnerability Prevention - Free Trial Greetings: Dugsong, Ohhara, Ryan Lee, Pilot, Sakai, Gonan and all the Korean Bugtruck Mailing List Subscribers Copyright (c) 1998-2006 eEye Digital Security Permission is hereby granted for the redistribution of this alert electronically. It is not to be edited in any way without express consent of eEye. If you wish to reprint the whole or any part of this alert in any other medium excluding electronic medium, please email alert@xxxxxxxx for permission. Disclaimer The information within this paper may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are no warranties, implied or express, with regard to this information. In no event shall the author be liable for any direct or indirect damages whatsoever arising out of or in connection with the use or spread of this information. Any use of this information is at the user's own risk.
