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managed email service

 

which scans emails before they arrive in the organisation and then scans emails for viruses 

when they are sent. For example, Symantec (

www.symantec.com/en/uk/products-solutions/

 Anti-  virus  software

Software to detect and 

eliminate viruses.

Figure 11.26

The geographic spread of the ‘Slammer’ worm 30 minutes after release

Source: ‘The geographic spread of the ‘Slammer’ worm’, http://www.caida.org/research/security/code-red/coderedv2_

analysis.xml, Copyright 2003 The Regents of the University of California.

Managed email 

service

Receipt and transmission 

of emails is managed by a 

third party.

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Chapter 11  Analysis and design

families/? fid=  symantec-  cloud

) scans 2.7 billion emails a day for 7,500 companies worldwide. 

In August 2008 it reported that:

● 

78% of messages were spam

● 

1 in 88 contained a virus

● 

1 in 522 was a 

phishing

 attempt.

Managed email services are likely to be more effective than using internal  anti-  virus software 

since the service providers are experts in this field. They will also be able to identify and 

respond to email worm attacks more rapidly. To summarise, organisations need a policy to 

be developed for use of  anti-  virus software. This should specify:

1 

The preferred  anti-  virus software to be used on all machines.

2 

The frequency and mechanism for updating  anti-  virus software.

3 

The frequency with which the whole  end-  user PC is  system-  scanned for viruses.

4 

Organisational blocking of attachments with uncommon extensions.

5 

Organisational disabling of macros in office applications.

6 

Scanning to be performed on mail servers when emails are first received and before viruses 

are sent.

7 

Recommendations on use of  spam-  filtering software.

8 

Back-up and recovery mechanisms.

Education of staff in identifying and then acting upon the different types of virus can also 

limit the impact of viruses. Some general instructions include the following:

1 

Do not open attachments to emails from people you don’t know (reduce transmission 

of email attachment viruses). Only open attachments which look legitimate, for example 

Word documents with relevant names. Some viruses use file extensions that are not com-

monly used such as .pif, .scr or .vbs. Viewing documents rather than opening them for 

editing can also reduce the risk of transmission.

2 

Download software only from the official source, and always check for viruses before 

installing the software (reduces risk of Trojan horse viruses).

3 

Disable or turn off macros in Word or Excel unless you use them regularly (reduces risk of 

 macro-  viruses).

4 

Back up important files daily if this function is not performed by a system administrator.