CipherTrust this week announced a new release of its IronMail secure email appliance that adds new spam-fighting features intended to drive up spam detection rates while reducing false positives.

With its new Enterprise Spam Profiler (ESP), IronMail aggregates the results of existing detection techniques to create a more reliable assessment of whether a given message is spam, says Matt Anthony, director of marketing for CipherTrust.

Previously, the product applied each of its detection techniques sequentially, which rendered some of them, such as Reverse DNS, all but useless because of their high false positive rates.

ESP is intended to take into account the strengths and weaknesses of each spam detection technique and factor that into its final probability rating of whether a message is spam. The detection techniques ESP applies include:

  • CipherTrust's Statistical Lookup Service, which compares message signatures or hashes to a database of known spam
  • Header analysis, which applies heuristics to identify telltale signs of spam, such as forged headers
  • Content filtering of keywords using Bayesian analysis
  • Reverse DNS lookup
  • Realtime Blackhole List support
  • Heuristic message scanning to identify new threats and spam outbreaks

    ESP comes with a default "confidence rating" for each technique that can be adjusted by administrators, Anthony says. As with previous versions of IronMail, based on the final probability rating administrators can decide what to do with a message -- ranging from logging to quarantine to rejecting.

    While CipherTrust has no specific statistics on how much more reliable ESP might be than previous techniques, Anthony says he expects it will deliver "slightly higher detection rates but much fewer false positives."

    Another new feature, Automatic Intelligent Whitelisting, is partly responsible for the expected reduction in false positives. The technology monitors outgoing traffic to determine legitimate correspondents for each user. It then adds those users to a white list, allowing traffic from those addresses to bypass the spam filter.

    The new version of IronMail is available now. Pricing starts at $27,000.