Email spam trends in 2020 and filtering improvements

  • Wednesday, 9th September, 2020
  • 10:20am

So far this year, our mail and security teams have noticed a significant uptick in attempts to send spam to our user base. Staying on top of these trends has been a top priority for our Abuse and Mail Infrastructure teams.

Across the email industry, a new trend is growing in malicious tactics that use Covid-19, a topic still gaining traction with cybercriminals and impacting all email providers. Google has detected 18 million malware and phishing messages a day directly related to Covid-19 through Gmail, in addition to more than 240 million Covid-related daily spam messages.

We have recently introduced improvements in our incoming spam filtering systems:

  • Introduced a greylisting system which allows the system to slow mail from unknown or suspicious sources for further analysis and rescanning by our content filters before delivery to the user. Greylisting is a method of defending email users against spam. A mail transfer agent (MTA) using greylisting will "temporarily reject" any email from a sender it does not recognize.
  • Released several patches to inbound anti-spam systems to improve accuracy of results.
  • Added new Real-Time Blacklists (RBL) data sources.
  • Monitoring alongside content filtering providers to analyze reports of missed spam and modify filters to catch similar patterns.
  • Introduced additional source blocking technology based on detailed log analysis and detection of additional identifying parameters.


We are also planning additional items to continue improvement:

  • Additional rate limiting capacity to slow down connections from unknown sources.
  • Changes to greylisting system to allow more flexibility for known senders.
  • Testing of additional content filtering engines.
  • Improvements to user feedback and spam data collection systems to improve response time to new threats. 


HostSellers takes spam seriously and we will continue to monitor closely and make ongoing adjustments to improve our user experience.

If you have any questions, please do not hesitate to contact our Support Department at any time.

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