Simple steps to defend against viruses

Use anti-virus software
Install anti-virus software on all of your desktops and servers, and ensure they are kept up to date. Because new viruses can spread extremely quickly, it is important to have an updating infrastructure in place which can update all the computers in your company seamlessly, frequently, and at short notice.

We recommend Sophos's anti-virus solutions because they can be automatically updated, ensuring the latest virus protection is in place against the latest threats even when your office is unmanned.

Run a consolidated email filtering solution at your email gateway as well to protect your business from the threats of email-borne viruses and spam.

And don't forget to protect your laptop computers and desktop computers used by home workers. Ensure they are running up-to-date virus protection as viruses and worms can easily use these devices to enter your business.

Set your Filtering
Consider filtering potentially malicious emails at the email gateway as this can provide a level of pro-active protection against new virus threats. You could:

• Block file types that are often virus carriers
  
  These include EXE, COM, PIF, SCR, VBS, SHS, CHM and BAT file types. It is unlikely that your organisation will ever need to receive files of these types from the outside world.
• Block any file with more than one file type extension
  
  Some viruses attempt to disguise their true executable nature by using "double extensions". Files such as LOVE-LETTER-FOR-YOU.TXT.VBS or ANNAKOURNIKOVA.JPG.VBS may appear to be ASCII text or a harmless graphic to the inexperienced.
• Ensure all executable code sent to your organisation is checked and approved
  
  Ensure that all executables received from the outside world via email goes directly to your IT department or, in the case of small businesses, your IT person, for checking and approval.
  
  This serves two purposes. First, your IT department (or person) can confirm not only that it is virus-free, but also properly licensed, unlikely to conflict with existing software applications, and is suitable (for instance, not pornographic). Second, IT will always know what software is installed on which computers.

Introduce an anti-virus policy
Produce a policy for safe computing and distribute it to all staff. Make sure every employee has read and understood the policy, and that they know who to speak to, if they have any questions.

Such a policy could include:

• A ban on downloading executables and documents directly from the internet.
• A ban on running unsolicited executables/documents/spreadsheets within the organisation.
• A ban on playing computer games or using screensavers which did not come with the operating system.
• An IT checking and approval system for executables that arrive via email from the outside world.

It could also ask staff to do the following:

• Save all Word documents as RTF (Rich Text Format) files as DOC files can harbour macro viruses.
• Treat with suspicion any newly arrived email that they weren't expecting.
• Forward any virus warnings or hoaxes directly to IT (and no-one else) to confirm whether they are genuine or not.
• Staff should inform IT immediately if they think their computer has been infected with a virus.

You could also download and share with your staff Sophos's easy-to-understand guide, Computer viruses demystified [PDF], which explains viruses, the damage they can do and methods of avoiding them.