Gloucester, UK-based MessageLabs already uses Symantec’s Brightmail technology for detecting spam, said its chief information security analyst Paul Wood, so traffic shaping is another layer in our defences.
It works by recognising patterns in the network that indicate spam is arriving. It then limits the bandwidth available to the incoming messages, pushing them back to the high-volume senders and effectively gumming up their network resources in what is tantamount to a reverse denial of service attack. This in turn should deter the spammers from further attacks for fear of additional congestion, Wood went on.
Traffic shaping works further down the OSI stack at the TCP (i.e. layer 4) level rather than up at the SMTP application level, acting as an initial security facility before you even get to the content filtering that looks at the SMTP header, Wood said. Symantec acquired the technology when it bought start-up TurnTide Inc in July last year.
The market requirement for MessageLabs to introduce traffic shaping into its AS service comes from the mushrooming problem of spam, already thought to average around 80% of all incoming email traffic for companies.
With the power of bot nets, spammers are able to launch what effectively becomes a distributed denial of service attack against a corporate user, generating hundreds of random addresses that don’t exist and tying up its resources in replying to the sender that that address is not recognised, said Wood.
The business rationale for the enhancement to its services, meanwhile, comes from the fact that MessageLabs is in an increasingly crowded market for mail filtering services. It leads the market in Europe, ahead of companies such as BlackSpider, but also faces the incoming challenge of Postini from the US, at the same time that it seeks entry into the US market too.
Differentiation is therefore key to standing out in the crowd, so the fact that Wood can now boast that we’re the first [mail filtering] service provider to do traffic shaping represents an attempt to stay ahead of the pack.
