Degradation of spam detection by Cyren services: What you should do now
Currently, we see a possible risk that spam detection by Cyren services could deteriorate. To minimise these risks, we recommend that all NoSpamProxy customers implement the following measures.
Install the latest version 14.0 of NoSpamProxy.
Updating your NoSpamProxy installation to version 14 guarantees that you will benefit from the latest features, improvements or bug fixes. In addition, 32Guards is only available from version 14 (see next point).
32Guards is on the one hand a filter that influences the calculation of the spam confidence level, and on the other hand an action that can directly reject threats temporarily or permanently. This action/filter ensures that metadata on email attachments and URLs are collected and evaluated. See Configuring actions and Configuring filters.
Activate the file-based virus scanner in the Malware Scanner action.
For information on how to activate it, see Configuring actions. Please also note the information under Malware scanner.
For additional protection, we recommend activating a local virus scanner such as Microsoft Defender and keeping it up to date.
Apply an Allowlist approach for attachment management in the content filter.
Specifically allow certain file types in the content filter and prohibit all other file types with an Any rule. This way you build up an email firewall and reduce the risk of infecting your systems. See Creating content filters.
Use blocklists to block spammers
To reject emails from unwanted senders, create a blocklist. For instructions on how to do this, see Creating a blocklist.
Use the Word matching filter
The Word matching filter allows you to define lists of words and phrases. These can then lead to the classification of the email as spam in case of matches in the email body or subject.
Check your filter settings
Over time, many adjustments are made in rules: an RBL provider is removed from the real-time blocklists filter because it had temporarily listed a partner, or you deactivate individual tests in the reputation filter. Therefore, check your filter settings and activate previously deactivated options to restore the original good filter performance and work with allowlists in the rule set in case of temporary problems with a partner. See Creating an allowlist.