|CERT-In Vulnerability Note
SQL Server Named Pipe Hijacking, Named Pipe Denial of Service and Buffer Overrun vulnerability
Original Issue Date:July 26, 2003
Severity Rating: MEDIUM
. Microsoft SQL Server 2000 64 bit all editions
. Microsoft SQL Server 2000 all editions SP3
. Microsoft SQL Server 2000 all editions SP3a
. Microsoft SQL Server 7.0 Service Pack 4
. Microsoft SQL Server 2000 Desktop Engine MSDE SP3
. Microsoft Data Engine MSDE 1.0
. Microsoft Data Engine MSDE 1.0 SP4
Microsoft SQL Server 7, 2000, and MSDE allows:
- local users go gain privileges by hijacking a named pipe during the authentication of another user, i.e the "Named Pipe Hijacking" vulnerability
- local or remote authenticated users to cause a "Denial of service" crash or hang via a long request to a named pipe
- local users to execute arbitrary code via a certain request to the Local Procedure Calls LPC port that leads to a "Buffer overflow."
This is a cumulative patch that includes the functionality of all previously released patches for SQL Server 7.0, SQL Server 2000, MSDE 1.0, and MSDE 2000. In addition, it eliminates three newly discovered vulnerabilities.
Named Pipe Hijacking vulnerability:
Upon system startup, SQL Server creates and listens on a specific named pipe for incoming connections to the server. A named pipe is a specifically named one-way or two-way channel for communication between a pipe server and one or more pipe clients. The named pipe is checked for verification of which connection attempts can log on to the system running SQL Server to execute queries against data that is stored on the server. A flaw exists in the checking method for the named pipe that could allow an attacker local to the system running SQL Server to hijack gain control of the named pipe during another clients authenticated logon password. This would allow the attacker to gain control of the named pipe at the same permission level as the user who is attempting to connect. If the user who is attempting to connect remotely has a higher level of permissions than the attacker, the attacker will assume those rights when the named pipe is compromised. To exploit this flaw, the attacker would need to be an authenticated user local to the system. This vulnerability provides no way for an attacker to remotely usurp control over the named pipe as per Microsoft release.
Named Pipe Denial of Service vulnerability:
In the same named pipes scenario that is mentioned in the "Named Pipe Hijacking" section, it is possible for an unauthenticated user who is local to the intranet to send a very large packet to a specific named pipe on which the system running SQL Server is listening and cause it to become unresponsive. This vulnerability would not allow an attacker to run arbitrary code or elevate their permissions, but it may still be possible for a denial of service condition to exist that would require that the server be restarted to restore functionality. Although it is unnecessary that the attacker be authenticated, to exploit this flaw the attacker would require access to the local intranet. Restarting the SQL Server will reinstate normal operations This flaw provides no method by which an attacker can gain access to the system or information contained in the database as per Microsoft release.
SQL Server Buffer Overrun vulnerability:
A flaw exists in a specific Windows function that may allow an authenticated user-with direct access to log on to the system running SQL Server-the ability create a specially crafted packet that, when sent to the listening local procedure call LPC port of the system, could cause a buffer overrun. If successfully exploited, this could allow a user with limited permissions on the system to elevate their permissions to the level of the SQL Server service account, or cause arbitrary code to run. To exploit this flaw, the attacker would need to be an authenticated user local to the system. This vulnerability cannot be remotely exploited as per Microsoft release.
System administrators should apply the security patch to affected systems.
Refer Microsoft Security Bulletin MS03-031
Microsoft Security Bulletin MS03-031
CAN-2003-0232 under review
The information provided herein is on "as is" basis, without warranty of any kind.
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