tcp_123
Explanation
The tcp_123 NDM flags interactive connections leaving the customer's network to destinations on TCP port 123. The Network Time Protocol service uses UDP port 123, but does not use TCP. In some cases malware will connect out to servers on TCP port 123 in order to evade detection. You may also see inbound TCP connections sourced from port 123 because this can evade poorly written firewall rules.
What to Look For
The use of TCP port 123 is almost never expected or authorized. Hosts initiating these connections should be checked to make sure that they are not infected with malware.
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Updated 14 days ago