How to choose antivirus software to run on computers that are running SQL Server

This article contains general guidelines to help you decide which kind of antivirus software to run on the computers that are running Microsoft SQL Server in your environment.

We strongly recommend that you individually assess the security risk for each computer that is running SQL Server in your environment and that you select the tools that are appropriate for the security risk level of each computer that is running SQL Server. Additionally, we recommend that before you roll out any virus-protection project, you test the whole system under a full load to measure any changes in stability and performance.

Virus protection software requires some system resources to execute. You must perform testing before and after you install your antivirus software to determine whether there is any performance effect on the computer that is running SQL Server.

Security risk factors

• The value to your business of the information that is stored on the computer.
• The required security level for that information.
• The cost of losing access to that information.
• The risk of either virus or bad information propagating from that computer.

High-risk servers

Any server is at some risk of infection. The highest risk servers generally meet one or more of the following criteria:

• The servers are on the public Internet.
• The servers have open ports to servers that are not behind a firewall.
• The servers read or execute files from other servers.
• The servers run HTTP servers, such as Internet Information Services (IIS) or Apache. (For example: SQL XML for SQL Server 2000.)
• The servers are also hosting file shares.
• The servers use SQL Mail to handle incoming or outgoing email messages.

Servers that do not meet the criteria for a high-risk server are generally at a lower risk, although not always.

Virus tool types

• Active virus scanning: This kind of scanning checks incoming and outgoing files for viruses.
• Virus sweep software: Virus sweep software scans existing files for file infection. It detects files after they are infected with a virus. This kind of scanning may cause the following SQL Server database recovery and SQL Server full-text catalog file issues:
  • If the virus sweep has opened a database file and still has it open when SQL Server tries to open the database (such as when SQL Server starts or when SQL Server opens a database that AutoClose has closed), the database to which the file belongs might be marked as suspect. The SQL Server database files typically have the .mdf, .ldf, and .ndf file suffixes.
  • If the virus sweep software has a SQL Server full-text catalog file open when the Microsoft Search service (MSSearch) tries to access the file, you may have problems with the full text catalog.
• Vulnerability scanning software: The Microsoft Security Tool Kit CD includes best practice guidelines, information about how to help secure your system, and service packs and updates that can protect your system against virus attacks. It also provides Microsoft tools to help you secure your systems and keep them secure. To download it, visit the following Microsoft website:
  http://www.microsoft.com/security/ (http://www.microsoft.com/security/)
• Antispyware software: Spyware and unwanted software refers to software that performs certain tasks on your computer, typically without your consent. For more information about how to help protect the computer from spyware and unwanted software, visit the following Microsoft website:
  http://www.microsoft.com/protect/computer/spyware/default.mspx (http://www.microsoft.com/protect/computer/spyware/default.mspx)
  Additionally, Microsoft has released the Microsoft Windows Malicious Software Removal Tool to help remove specific, prevalent malicious software from computers that are running Windows Server 2003, Windows XP, or Microsoft Windows 2000.  For more information about the Microsoft Windows Malicious Software Removal Tool, click the following article number to view the article in the Microsoft Knowledge Base:
  890830  (http://support.microsoft.com/kb/890830/ ) The Microsoft Windows Malicious Software Removal Tool helps remove specific, prevalent malicious software from computers that are running Windows Vista, Windows Server 2003, Windows XP, or Windows 2000

Directories and file-name extensions to exclude from virus scanning

When you configure your antivirus software settings, make sure that you exclude the following files or directories (as applicable) from virus scanning. Doing this improves the performance of the files and helps make sure that the files are not locked when the SQL Server service must use them. However, if these files become infected, your antivirus software cannot detect the infection.

Note For more information about the default file locations for SQL Server, refer to the "File Locations for Default and Named Instances of SQL Server" topic for your specific version of SQL Server in SQL Server Books Online.

SQL Server 2008 R2SQL Server 2008SQL Server 2005

• SQL Server data files
  
  These files usually have one of the following file-name extensions:
  • .mdf
  • .ldf
  • .ndf
• SQL Server backup files
  
  These files frequently have one of the following file-name extensions:
  • .bak
  • .trn
• Full-Text catalog files
  • Default instance: Program Files\Microsoft SQL Server\MSSQL\FTDATA
  • Named instance: Program Files\Microsoft SQL Server\MSSQL$instancename\FTDATA
  
  
• Trace files
  
  These files usually have the .trc file-name extension. These files can be generated either when you configure profiler tracing manually or when you enable C2 auditing (http://msdn.microsoft.com/en-us/library/ms187634.aspx)  for the server.
• SQL audit files (for SQL Server 2008 or later versions)
  
  These files have the .sqlaudit file-name extension. For more information, see the following topic in SQL Server Books Online:

  Audits (General Page) (http://msdn.microsoft.com/en-us/library/cc280649.aspx)
• SQL query files
  
  These files typically have the .sql file-name extension and contain Transact-SQL statements.
  
• The directory that holds Analysis Services data
  
  Note The directory that holds all Analysis Services data is specified by the DataDir property of the instance of Analysis Services. By default, the path of this directory is C:\Program Files\Microsoft SQL Server\MSSQL.X\OLAP\Data. If you use Analysis Services 2000, you can view and change the data directory by using Analysis Manager. To do this, follow these steps:
  1. In Analysis Manager, right-click the server, and then click Properties.
  2. In the Properties dialog box, click the General tab. The directory appears under Data folder.
• The directory that holds Analysis Services temporary files that are used during Analysis Services processing
  
  Note For Analysis Services 2005 and later versions, temporary files during processing are specified by the TempDir property of the instance of Analysis Services. By default, this property is empty. When this property is empty, the default directory is used. This directory is C:\Program Files\Microsoft SQL Server\MSSQL.X\OLAP\Data. If you use Analysis Services 2000, you can view and change the directory that holds temporary files in Analysis Manager. To do this, follow these steps:
  1. In Analysis Manager, right-click the server, and then click Properties.
  2. In the Properties dialog box, click the General tab.
  3. On the General tab, notice the directory under Temporary file folder.
  
  Optionally, you can add a second temporary directory for Analysis Services 2000 by using the TempDirectory2 registry entry. If you use this registry entry, consider excluding from virus scanning the directory to which this registry entry points. For more information about the TempDirecotry2 registry entry, see the "TempDirectory2" section of the following Microsoft Developer Network (MSDN) website:
  
  http://msdn.microsoft.com/en-us/library/aa902654(SQL.80).aspx#sql2k_anservregsettings_topic52 (http://msdn.microsoft.com/en-us/library/aa902654(SQL.80).aspx#sql2k_anservregsettings_topic52)
  
  
  
• Analysis Services backup files
  
  Note By default, in Analysis Services 2005 and later versions, the backup file location is the location that is specified by the BackupDir property. By default, this directory is C:\Program Files\Microsoft SQL Server\MSSQL.X\OLAP\Backup. You can change this directory in the properties of the instance of Analysis Services. Any backup command can point to a different location. Or, the backup files may be copied elsewhere.
  
• The directory that holds Analysis Services log files
  
  Note By default, in Analysis Services 2005 and later versions, the log file location is the location that is specified by the LogDir property. By default, this directory is C:\Program Files\Microsoft SQL Server\MSSQL.X\OLAP\Log.
• Directories for any Analysis Services 2005 and later-version partitions that are not stored in the default data directory
  
  Note When you create the partitions, these locations are defined in the Storage location section of the Processing and Storage Locations page of the Partition Wizard.

Processes to exclude from virus scanning

SQL Server 2008 R2

• %ProgramFiles%\Microsoft SQL Server\MSSQL10_50.<Instance Name>\MSSQL\Binn\SQLServr.exe
• %ProgramFiles%\Microsoft SQL Server\MSSQL10_50.<Instance Name>\Reporting Services\ReportServer\Bin\ReportingServicesService.exe
• %ProgramFiles%\Microsoft SQL Server\MSSQL10_50.<Instance Name>\OLAP\Bin\MSMDSrv.exe

SQL Server 2008

• %ProgramFiles%\Microsoft SQL Server\MSSQL10.<Instance Name>\MSSQL\Binn\SQLServr.exe
• %ProgramFiles%\Microsoft SQL Server\MSSQL10.<Instance Name>\Reporting Services\ReportServer\Bin\ReportingServicesService.exe
• %ProgramFiles%\Microsoft SQL Server\MSSQL10.<Instance Name>\OLAP\Bin\MSMDSrv.exe

SQL Server 2005

• %ProgramFiles%\Microsoft SQL Server\MSSQL.1\MSSQL\Binn\SQLServr.exe
• %ProgramFiles%\Microsoft SQL Server\MSSQL.3\Reporting Services\ReportServer\Bin\ReportingServicesService.exe
• %ProgramFiles%\Microsoft SQL Server\MSSQL.2\OLAP\Bin\MSMDSrv.exe

Considerations for clustering

You can run antivirus software on a SQL Server cluster. However, you must make sure that the antivirus software is a cluster-aware version. Contact your antivirus vendor about cluster-aware versions and interoperability.

If you are running antivirus software on a cluster, make sure that you also exclude these locations from virus scanning:

• Q:\ (Quorum drive)
• C:\Windows\Cluster

If you back up the database to a disk or if you back up the transaction log to a disk, you can exclude the backup files from the virus scanning.

For updated security-related information, we recommend that you subscribe to the security warning alias. To subscribe, visit the following Microsoft website, and then view the Security Bulletins section:To find general information about SQL Server security, visit the following Microsoft website. (This information includes best practices, various security models, and security bulletins.) For more information about additional antivirus considerations on a cluster, click the following article number to view the article in the Microsoft Knowledge Base: For general recommendations from Microsoft for scanning on Enterprise systems, click the following article number to view the article in the Microsoft Knowledge Base: