Vulnerability Note VU#700575

Buffer overflows in Microsoft SQL Server 7.0 and SQL Server 2000

Overview

There is a buffer overflow in Microsoft SQL Server 2000 and SQL Server 7.0 which could allow an intruder to execute arbitrary code on vulnerable systems.

I. Description

Microsoft Windows SQL Server 2000 and SQL Server 7.0 contain a buffer overflow in functions associated with text messages. For more information, see

http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS01-060.asp
http://www.atstake.com/research/advisories/2001/index_q1.html

Quoting from MS01-060,

The functions that contain the unchecked buffers are associated with creating, and in some cases displaying, text messages. SQL Server provides several functions that enable a database query to create formatted text.

Intruders who can execute queries containing these functions can exploit a buffer overflow. An intruder who could load and execute queries of his own choosing would be able to exploit this vulnerability. Other intruders may be able to execute this vulnerability as well. Again, quoting from MS01-060,

If the database search [or other routine] called one of the affected functions, it might be possible for an attacker to construct a query that would cause [an affected] function to be called in such a way as to exploit the vulnerability. Clearly, this would require intimate knowledge of the internals of the database query.

On the other hand, if the database query were poorly implemented, the attacker might not need to know its internal details in order to exploit the vulnerability. One frequently exploited implementation error occurs when a database query doesn’t adequately check its inputs before using them. In some cases, this would make it possible for an attacker to embed database commands – including, in this case, calls to the affected functions – within database query parameters. This underscores the need to always check input parameters before using them.

Applying the patch protects against all these attack scenarios, though it is still wise to ensure that input parameters to SQL Server queries are closely examined to guard against other possible vulnerabilities or unauthorized access.

II. Impact

Intruders can execute arbitrary code with the privileges of the SQL server process.

III. Solution

Apply a patch as described in MS01-060.

Systems Affected

Vendor	Status	Date Updated
Microsoft	Vulnerable	21-Dec-2001

References

http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS01-060.asp
http://www.atstake.com/research/advisories/2001/index_q1.html
http://www.microsoft.com/technet/treeview/default.asp?url=/technet/prodtechnol/sql/deploy/confeat/c05ppcsq.asp
http://www.microsoft.com/technet/treeview/default.asp?url=/technet/prodtechnol/sql/maintain/security/sqlc2.asp
http://www.microsoft.com/Downloads/Release.asp?ReleaseID=35066
http://www.microsoft.com/Downloads/Release.asp?ReleaseID=35067
http://www.uniras.gov.uk/l1/l2/l3/brief2001/UNIRAS%20Briefing%20-%2025001%20-%20%20Microsoft%20-%20SQL%20Server%20Text%20Formatting%20Functions%20Contain%20unchecked%20Buffers%20(MS01-060).txt

Credit

Our thanks to Microsoft for the information contained in their bulletin. Microsoft has publicly thanked Chris Anley of @Stake for reporting this issue to them.

This document was written by Shawn V. Hernan.

Other Information

Date Public	12/20/2001
Date First Published	12/21/2001 01:16:08 AM
Date Last Updated	01/09/2002
CERT Advisory
CVE Name	CAN-2001-0542
US-CERT Technical Alerts
Metric	15.19
Document Revision	7

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