Are open ports a security risk?

Related questions

1. How does UDP port scan work?
2. What does it mean if a port is open?
3. What is TCP port scanning?
4. Are open ports safe?
5. What are port scanning tools?
6. What is the proper response for a null scan if the port is open?
7. What ports does UDP use?
8. How many ports can a server have?
9. What is Angry IP scanner used for?
10. What port is UDP on?

Tags

1. #selected
2. #attack
3. #factors
4. #through
5. #simply
6. #ports
7. #attackers
8. #whether
9. #attacks
10. #natively
11. #leave
12. #malware
13. #service
14. #include
15. #underlying
16. #potentially
17. #risks
18. #other
19. #their
20. #secure