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Microsoft SQL Server Webtasks privilege upgrade (#NISR17102002)
From: "David Litchfield" <david () ngssoftware com>
Date: Thu, 17 Oct 2002 14:23:54 +0100
NGSSoftware Insight Security Research Advisory
Name: Microsoft SQL Server Webtasks privilege elevation
Systems: Microsoft SQL Server 2000 and 7
Severity: High Risk
Vendor URL: http://www.microsoft.com/
Author: David Litchfield (david () ngssoftware com)
Advisory URL: http://www.ngssoftware.com/advisories/mssql-webtasks.txt
Date: 17th October 2002
Advisory number: #NISR17102002
Using a number of flaws in the webtask functionality of Microsoft SQL Server
an attacker may gain control of the database by elevating their privileges.
The xp_runwebtask stored procedure fails to set permissions properly when
executed and runs with the privileges of the SQL Server. xp_runwebtask can
be executed by 'PUBLIC'.
The permissions of the table that stores webtasks, namely
msdb.dbo.mswebtasks, are set loosely allowing 'PUBLIC' to INSERT, UPDATE,
DELETE and SELECT.
By updating a webtask owned by the database owner and then running it
through xp_runwebtask an attacker may elevate their privileges. In terms of
exploitation an attacker may choose to run OS commands or add themselves to
the SYSADMIN group.
NGSSoftware alerted Microsoft to these problems on the 23rd of August.
Microsoft has released a patch that addresses these issues. For more details
A check and fix for these problems already exists in NGSSQuirreL, an
advanced SQL Server security management tool, of which more information
is available from the NGSSite: http://www.nextgenss.com/.
- Microsoft SQL Server Webtasks privilege upgrade (#NISR17102002) David Litchfield (Oct 17)