INFORMATION BULLETIN
INFORMATION BULLETIN
| 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 reccommends 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. |
| VULNERABILITY ASSESSMENT: |
The risk is LOW. There are several mitigating factors, including one of timing the access to the system. |
[****** Begin Microsoft Bulletin ******]
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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:
www.microsoft.com/technet/security/bulletin/MS01-032.asp.
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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
www.microsoft.com/technet/security/bulletin/ms01-032.asp
for information on obtaining this patch.
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[****** End Microsoft Bulletin ******]
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