Attachment detection by Cyren Premium AntiVirus
The Cyren Premium AntiVirus scanner is part of the Malware Scanner action and can be used if NoSpamProxy Protection is licensed. Cyren Premium AntiVirus checks attachments that are attached to an email. In doing so, it carries out two basic checks:
- Local checks against definitions
- The definitions are regularly downloaded from the Cyren servers. In case of access problems to the Cyren servers, the definitions must not be older than two days.
- During the check, the attachment is placed in the directory C:\ProgramData\Net at Work Mail Gateway\Cyren\Temp, checked and deleted again.
- Live checks – Zero Hour Protection
- Check for conspicuous attachments in the recent past. A hash value is generated and sent to Cyren, which then sends a response with the corresponding classification by Cyren.
Unlike with the Cyren AntiSpam filter, the NoSpamProxy support has no way of influencing this behaviour in the case of a misclassification.
In the case of misclassifications – i.e. false positives or false negatives – the sender or the recipient of the email must always contact Cyren and have this corrected accordingly.
A description of the process can be found on the respective Cyren support page.
In case of local problems or missing definitions, please refer to the Knowledge Base article Cyren Engines – Troubleshooting
Note
To ensure parallel operation with other locally installed virus scanners on the gateway role, please refer to the Knowledge Base article How to configure on-access virus scanners and define the exceptions as described!
Further information
- For information on the detection by the Cyren AntiSpam Filter, please refer to the Knowledge Base article Recognition of emails by the Cyren AntiSpam filter.
- For information about detection by the Cyren IP Reputations filter, see Knowledge Base article Detection of IP addresses by the Cyren IP Reputation filter
- For information on detection by the Cyren URL classification service, see the Knowledge Base article How to influence URL classifications.
- Troubleshooting information for all Cyren services can be found in the Knowledge Base article Cyren Engines – Troubleshooting.
