Vulnerability Note VU#696644

Microsoft SQL Server fails to properly validate parameters to the sp_replwritetovarbin extended stored procedure

Original Release date: 24 Dec 2008 | Last revised: 10 Feb 2009

Overview

A vulnerability in the Microsoft SQL Server sp_replwritetovarbin extended stored procedure could allow an authenticated attacker to execute arbitrary code on an affected server.

Description

Some versions of Microsoft SQL Server contain a vulnerability in the sp_replwritetovarbin stored procedure. The vulnerability could allow an attacker to modify heap memory and potentially execute arbitrary code. The vulnerability is described in SEC Consult Security Advisory < 20081209-0 >. Microsoft Security Bulletin MS09-004 provides further details, including affected database versions and workarounds.

In order to access sp_replwritetovarbin, an attacker would need to authenticate to the database first. A separate SQL injection vulnerability in a web application could allow a remote, unauthenticated attacker to exploit the sp_replwritetovarbin vulnerability with the user credentials of the web application. Microsoft Security Advisory (954462) provides detection and mitigation advice for SQL injection vulnerabilities.

Exploit code is publicly available for this vulnerability.

Impact

A local or remote authenticated attacker may be able to execute arbitrary code with the privileges of the SQL Server on the affected system. In the case of a SQL injection vulnerability in a web application that uses a vulnerable database, a remote attacker may be able to exploit the sp_replwritetovarbin vulnerability with credentials of the web application.

Solution

Apply an update
This issue is addressed in Microsoft Security Bulletin MS09-004.

Workarounds

Deny execute permissions on sp_replwritetovarbin as described in Microsoft Security Bulletin MS09-004.

Alternatively, remove sp_replwritetovarbin using sp_dropextendedproc as described in SEC Consult Security Advisory < 20081209-0 > and "Removing an Extended Stored Procedure from SQL Server."

Removing execute permissions or removing sp_replwritetovarbin may impact application functionality.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
Microsoft CorporationAffected19 Dec 200810 Feb 2009
If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A N/A

References

Credit

This vulnerability was reported by Bernhard Mueller of SEC Consult Vulnerability Lab.

This document was written by Chad R Dougherty and Art Manion.

Other Information

  • CVE IDs: CVE-2008-5416
  • US-CERT Alert: TA09-041A
  • Date Public: 09 Dec 2008
  • Date First Published: 24 Dec 2008
  • Date Last Updated: 10 Feb 2009
  • Severity Metric: 4.45
  • Document Revision: 18

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