8.11 Maintaining and Supporting the Network 
8.11.5 The need to frequently update virus signatures
It is important to frequently update virus signatures, which are used by the virus scanning software when eliminating viruses. These signature files are updated by the vendor and either mailed to or available on the vendor's web page for the user. An ongoing network maintenance strategy should be to update virus signatures frequently. Because new viruses are
developed daily, within a few months, what was effective anti-virus software can become useless.