A zero-day crypto-worm is quickly spreading through the internal network on port 25 and exploiting a software vulnerability found within the email servers.
Which of the following countermeasures needs to be implemented as soon as possible to mitigate the worm from continuing to spread?
A. Implement a traffic sinkhole.
B. Block all known port/services.
C. Isolate impacted servers.
D. Patch affected systems.