What actual controls can you deploy against the fraudsters?
The main issue you face is that while there are a number of Email technical controls which you can deploy – and which we cover shortly – you are entirely dependent upon the recipient as to whether they acknowledge, observe and follow these controls. Many ISPs will observe some of these controls for mail systems they operate themselves as it is in their interest to not fill their own infrastructure with unwanted Email, however, is likely to be quite different when a user has their own Email infrastructure. Of course an ‘own Email infrastructure’ can range from a large organisation with an ‘enterprise Email infrastructure’ right down to an individual operating their own mail server. In these cases adoption of the following spam controls is likely to be more sporadic – meaning they could have no effect at all.
Another key issue to consider with these technical controls is that they do not only help mail systems identify fraudulent Email, they also work in reverse and help mail systems identify legitimate mail. Consequently, by implementing these controls you not only increase the chances that fraudulent Email will be identified and discarded, but you simultaneously increase the chances that genuine Email will be identified and delivered. Remember, fraudulent Email claiming to be from your domain not only fills customer’s mailboxes with spam, it also increases the chance that both automated anti-spam systems and indeed your customers will start rejecting your legitimate Email in error. This is a key aspect of the impact fraudulent Email has on trust in your brand and your legitimate communications.
Therefore, the following technical controls are not just relevant to the security community and CISO, the Marketing Director should be insisting these control be implemented so as to increase the probability marketing communications are actually received and consumed by the intended recipient. Without these controls, once your brand comes under attack, you stand a high probability of a large proportion of your genuine communications being discarded.