Viruses are a type of third-party application designed with malicious intent to cause harm to computer systems. These applications are generically termed malware, as are trojan horse, worm, and spyware applications.
BlackBerry tools provide effective anti-virus protections for a BlackBerry deployment. They use containment methods that are designed to prevent malware that might gain access to the BlackBerry smartphone from causing damage to the BlackBerry smartphone, its applications and its data, and also to the corporate network.

Anti-virus protection on all BlackBerry smartphones (BlackBerry Enterprise Solution and BlackBerry Internet Service)

BlackBerry smartphone applications include inherent virus protection and spyware protection that is designed to contain and prevent the spread of viruses and spyware to other applications. Application controls are available on BlackBerry smartphones that are running on a BlackBerry Enterprise Server or on the BlackBerry Internet Service. BlackBerry smartphone users can use the application controls on their BlackBerry smartphones to prevent the installation of specific third-party applications and to limit the permissions of third-party applications. See the “BlackBerry Internet Service Security Feature Overview” for more information on using BlackBerry smartphone application controls to protect a BlackBerry smartphone running on the BlackBerry Internet Service against malware.

Anti-virus protection through the BlackBerry Enterprise Solution

The BlackBerry Enterprise Solution is designed to provide anti-virus protection through its malware protection. The BlackBerry Enterprise Solution includes tools that provide out-of-the-box protection against all malware. Administrators can use IT policy and application control policies on the BlackBerry Enterprise Server, and BlackBerry smartphone users can use application controls on BlackBerry smartphones to contain malware by controlling third-party Java application access to BlackBerry smartphone resources and applications. See “Protecting the BlackBerry device platform against malware” for more information on using the BlackBerry Enterprise

Solution tools to protect a BlackBerry deployment against malware.

The BlackBerry® Internet Service has an anti-spam system that is designed to block spam email messages that are sent to your BlackBerry email address. This feature helps to protect you against the inconvenience and potential privacy threat of email messages that are not intended specifically for you.

For additional control of spam email messages, you can create email message filters to prevent unwanted email messages from being delivered to your BlackBerry device.

taken from BlackBerry User Group Malaysia