I wonder if anyone can help me clarify the following, we start receiving standard ATP alerts for the past month as per bellow, usually im able to investigate this alerts and they either are DNS recursive queries performed by out forwarders on Spam domain emails received and rejected by the SMTP proxy, or Web sessions hijack attempts trying to redirect traffic to malicious domains, but recently i been baffled by a a recurrent alert as bellow where im not able to make much sense, i parsed the logs for our SMTP proxy that shows traffic to a Tor node from what i can only assume being SMTP connections rejected by the UTM does anyone have any idea on this ?
A threat has been detected in your network The source IP/host listed below was found to communicate with a potentially malicious site outside your company.
Advanced Threat ProtectionDetails Total Events: 2 User/Host Threat Name Destination Events Origin 1 192.168.7.250 C2/Generic-A 184.108.40.206 2 192.168.7.250 C2/Generic-A 220.127.116.11
Got the same problem. Sophos was pointing to the internal DNS. Then I changed everything to best practice. Internal DNS --> Sophos --> WAN.
Still finding the connection in the SMTP proxy…
Still finding the connection in the SMTP proxy log, but no ATP is raised:
2022:01:23-06:08:00 utm-2 exim-in: 2022-01-23 06:08:00 TLS error on connection from tor-exit-1.zbau.f3netze.de [18.104.22.168]:10578 SSL_accept: TCP connection closed by peer
Thank you! This helped me solving the issue. But I keep wondering: Why does SOPHOS UTM block the forwarded DNS Request (which itself pushed to the internal DNS Server) instead of the SMTP connection?