__________________________________________________________
The U.S. Department of Energy
Computer Incident Advisory Center
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/ | /_\ /
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INFORMATION BULLETIN
Microsoft SQL Query Method Vulnerability
June 13, 2001 18:00 GMT Number L-095
______________________________________________________________________________
PROBLEM: A problem exists in the client connection termination to the
SQL server. Access to the cached administrators 'sa' session is
possible.
PLATFORM: Microsoft SQL Server 2000 and SQL Server 7.0 NOTE: The server
is only vulnerable if it is configured to use 'mixed mode'.
Microsoft recommends against using this mode.
DAMAGE: Any user reactivating the cached 'sa' session would gain full
system privileges. This would give the user the capability of
running code of their choice and have full control of the
server.
SOLUTION: Apply the patch provided by Microsoft.
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VULNERABILITY The risk is LOW, as there are several mitigating factors,
ASSESSMENT: including one of timing the access to the system.
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[****** Begin Microsoft Bulletin ******]
- ----------------------------------------------------------------------
Title: SQL Query Method Enables Cached Administrator Connection
to be Reused
Date: 12 June 2001
Software: Microsoft SQL Server 2000 and SQL Server 7.0
Impact: Privilege elevation
Bulletin: MS01-032
Microsoft encourages customers to review the Security Bulletin at:
http://www.microsoft.com/technet/security/bulletin/MS01-032.asp.
- ----------------------------------------------------------------------
Issue:
======
When a client connection to a SQL Server is terminated, it remains
cached for a short period of time for performance reasons. One SQL
query method contains a flaw that has the effect of making it
possible for one user's query to reuse a cached connection that
belonged to the sa account.
Exploiting this vulnerability would enable an attacker to execute the
query using the administrator's security context. This would give
her the ability to take any desired action on the database;
moreover, it would give her the ability to run extended stored
procedures, thereby giving her the opportunity to run code of her
choice and assume de facto control of the server itself.
Mitigating Factors:
====================
- The vulnerability only affects servers configured to use Mixed mode.
Microsoft strongly recommends against using Mixed Mode, and
recommends using Windows Authentication mode instead. Customers who
have configured their servers to use Windows Authentication mode
are not affected by this vulnerability.
- Terminated connections are only cached for a short period. The
attacker would need to time her attack in order to occur during the
period when an administrator's connection was in the cache.
- The query method at issue here can only be executed by an
authenticated user. Not only would this limit the number of users
who could exploit the vulnerability, it also would allow the action
to be audited.
Patch Availability:
===================
- A patch is available to fix this vulnerability. Please read the
Security Bulletin
http://www.microsoft.com/technet/security/bulletin/ms01-032.asp
for information on obtaining this patch.
- ---------------------------------------------------------------------
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"AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL
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OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.
[****** End Microsoft Bulletin ******]
_______________________________________________________________________________
CIAC wishes to acknowledge the contributions of Microsoft 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
(DOE) and the emergency backup response team for the National
Institutes of Health (NIH). CIAC is located at the Lawrence Livermore
National Laboratory in Livermore, California. CIAC is also a founding
member of FIRST, the Forum of Incident Response and Security Teams, a
global organization established to foster cooperation and coordination
among computer security teams worldwide.
CIAC services are available to DOE, DOE contractors, and the NIH. CIAC
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PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing
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This document was prepared as an account of work sponsored by an
agency of the United States Government. Neither the United States
Government nor the University of California nor any of their
employees, makes any warranty, express or implied, or assumes any
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