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                       The U.S. Department of Energy
                     Computer Incident Advisory Center
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                             INFORMATION BULLETIN

              Microsoft SQL Server Unchecked Buffer Vulnerabilities
                     [Microsoft Security Bulletin MS02-020]

April 18, 2002 20:00 GMT                                          Number M-069
______________________________________________________________________________
PROBLEM:       Several of the Microsoft-provided extended stored procedures 
               have a flaw in that they fail to perform input validation 
               correctly. 
PLATFORM:      Microsoft SQL Server 7.0 
               Microsoft SQL Server 2000 
DAMAGE:        The attacker could cause the SQL server service to fail or
               run arbitrary code of choice.
SOLUTION:      Apply the patch supplied by vendor. 
______________________________________________________________________________
VULNERABILITY  The risk is MEDIUM. The effect of exploiting the vulnerability 
ASSESSMENT:    would depend on the specific configuration of the SQL Server. 
______________________________________________________________________________
LINKS: 
 CIAC BULLETIN:      http://www.ciac.org/ciac/bulletins/m-069.shtml 
 ORIGINAL BULLETIN:                                                           
                     http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS02-020.asp 
______________________________________________________________________________

[***** Start Microsoft Security Bulletin MS02-020 *****]

Microsoft Security Bulletin MS02-020

SQL Extended Procedure Functions Contain Unchecked Buffers (Q319507)
Originally posted: April 17, 2002

Summary
Who should read this bulletin: Database administrators using 
Microsoft® SQL Server™ 

Impact of vulnerability: Run code of attacker’s choice 

Maximum Severity Rating: Moderate 

Recommendation: Apply the patch immediately to affected systems 

Affected Software: 

Microsoft SQL Server 7.0 
Microsoft SQL Server 2000 

Technical details

Technical description: 

SQL Server 7.0 and 2000 provide for extended stored procedures, which 
are external routines written in a programming language such as C. These 
procedures appear to users as normal stored procedures and are executed 
in the same way. SQL Server 7.0 and 2000 include a number of extended 
stored procedures which are used for various helper functions. 

Several of the Microsoft-provided extended stored procedures have a flaw 
in common – namely, they fail to perform input validation correctly, and 
are susceptible to buffer overruns as a result Exploiting the flaw could 
enable an attacker to either cause the SQL Server service to fail, or to 
cause code to run in the security context in which SQL Server is running. 
SQL Server can be configured to run in various security contexts, and by 
default runs as a domain user. The precise privileges the attacker could 
gain would depend on the specific security context that the service runs 
in. 

An attacker could exploit this vulnerability in one of two ways. Firstly, 
the attacker could attempt to load and execute a database query that calls 
one of the affected functions. Secondly, if a web-site or other database 
front-end were configured to access and process arbitrary queries, it could 
be possible for the attacker to provide inputs that would cause the query 
to call one of the functions in question with the appropriate malformed 
parameters. 

Mitigating factors: 

The effect of exploiting the vulnerability would depend on the specific 
configuration of the SQL Server service. SQL Server can be configured to 
run in a security context chosen by the administrator. By default, this 
context is as a domain user. If the rule of least privilege has been followed, 
it would minimize the amount of damage an attacker could achieve. 

The vector for exploiting this vulnerability could be blocked by following 
best practices. Specifically, untrusted users should not be able to load and 
execute queries of their choice on a database server. In addition, publicly 
accessible database queries should filter all inputs prior to processing. 

Severity Rating:  
                 Internet Servers    Intranet Servers   Client Systems 
SQL Server 7.0      Moderate             Moderate          Moderate 
SQL Server 7.0      Moderate             Moderate          Moderate 

The above assessment is based on the types of systems affected by the 
vulnerability, their typical deployment patterns, and the effect that 
exploiting the vulnerability would have on them. While the vulnerability 
could potentially allow an attacker to run code on the server, best practices 
would limit the ability to exploit the vulnerability and the damage that 
could be achieved by a successful attack. 

Vulnerability identifier: CAN-2002-0154 

Tested Versions:
Microsoft tested SQL Server 7.0 and 2000 to assess whether they are affected 
by these vulnerabilities. Previous versions are no longer supported, and may 
or may not be affected by these vulnerabilities.

Patch availability
Download locations for this patch 
Microsoft SQL Server 7.0:
The patch for this issue is available in the SQL 7.0 Cumulative Security 
patch at http://support.microsoft.com/support/misc/kblookup.asp?id=Q318268 
Microsoft SQL Server 2000: 
The patch for this issue is available in the SQL Server 2000 Cumulative 
Security patch at: 
   http://support.microsoft.com/support/misc/kblookup.asp?id=Q316333 

Additional information about this patch

Installation platforms: 
The SQL Server 7.0 patch can be installed on systems running 
SQL Server 7.0 Service Pack 3. 
The SQL Server 2000 patch can be installed on systems running 
SQL Server 2000 Service Pack 2. 

Inclusion in future service packs:
The fix for this issue will be included in: 

SQL Server 7.0 Service Pack 4 
SQL Server 2000 Service Pack 3 

Reboot needed:
No. The SQL Server service only needs to be restarted after applying the 
patch. 

Superseded patches:MS02-007 

Verifying patch installation:

SQL Server 7.0: 
To ensure you have the fix installed properly, verify the individual files 
by consulting the date/time stamp of the files listed in the file manifest 
in Microsoft Knowledge Base article at 
http://support.microsoft.com/support/misc/kblookup.asp?id=Q318268 

SQL Server 2000: 
To ensure you have the fix installed properly, verify the individual files 
by consulting the date/time stamp of the files listed in the file manifest 
in Microsoft Knowledge Base article at 
http://support.microsoft.com/support/misc/kblookup.asp?id=Q316333 

Caveats:
None 

Localization:
Patches are available for each supported SQL Server Language. 

Obtaining other security patches: 
Patches for other security issues are available from the following locations: 

Security patches are available from the Microsoft Download Center, and can be 
most easily found by doing a keyword search for "security_patch". 
Patches for consumer platforms are available from the WindowsUpdate web site 
All patches available via WindowsUpdate also are available in a 
redistributable form from the WindowsUpdate Corporate site. 

Other information: 
Support: 

Microsoft Knowledge Base article Q319507 discusses this issue and will be 
available approximately 24 hours after the release of this bulletin. 
Knowledge Base articles can be found on the Microsoft Online Support web site. 

Technical support is available from Microsoft Product Support Services. There 
is no charge for support calls associated with security patches. 

Security Resources: The Microsoft TechNet Security Web Site provides 
additional information about security in Microsoft products. 

Disclaimer: 
The information provided in the Microsoft Knowledge Base is provided "as is" 
without warranty of any kind. Microsoft disclaims all warranties, either 
express or implied, including the warranties of merchantability and fitness 
for a particular purpose. In no event shall Microsoft Corporation or its 
suppliers be liable for any damages whatsoever including direct, indirect, 
incidental, consequential, loss of business profits or special damages, 
even if Microsoft Corporation or its suppliers have been advised of the 
possibility of such damages. Some states do not allow the exclusion or 
limitation of liability for consequential or incidental damages so the 
foregoing limitation may not apply. 

Revisions: 

V1.0 (April 17, 2002): Bulletin Created. 

[***** End Microsoft Security Bulletin MS02-020 *****]

_______________________________________________________________________________

CIAC wishes to acknowledge the contributions of Microsoft Corporation for the 
information contained in this bulletin.
_______________________________________________________________________________


CIAC, the Computer Incident Advisory Center, is the computer
security incident response team for the U.S. Department of Energy
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