[Full-disclosure] EEYE: Workstation Service NetpManageIPCConnect Buffer Overflow

Type securityvulns
Reporter Securityvulns
Modified 2006-11-14T00:00:00


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@eeye.com.

Credit: Discovery: JeongWook Matt Oh Additional Research: Derek Soeder

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