CertNexus cfr-310 online test

Question 1

A network security analyst has noticed a flood of Simple Mail Transfer Protocol (SMTP) traffic to
internal clients. SMTP traffic should only be allowed to email servers. Which of the following
commands would stop this attack? (Choose two.)

• A. iptables -A INPUT -p tcp –dport 25 -d x.x.x.x -j ACCEPT
• B. iptables -A INPUT -p tcp –sport 25 -d x.x.x.x -j ACCEPT
• C. iptables -A INPUT -p tcp –dport 25 -j DROP
• D. iptables -A INPUT -p tcp –destination-port 21 -j DROP
• E. iptables -A FORWARD -p tcp –dport 6881:6889 -j DROP

Answer:

AC

Question 2

A secretary receives an email from a friend with a picture of a kitten in it. The secretary forwards it to
the
~COMPANYWIDE mailing list and, shortly thereafter, users across the company receive the following
message:
You seem tense. Take a deep breath and relax!
The incident response team is activated and opens the picture in a virtual machine to test it. After a
short analysis, the following code is found in C:
\Temp\chill.exe:Powershell.exe Command do {(for /L %i in (2,1,254) do shutdown /r /m Error!
Hyperlink reference not valid.> /f /t / 0 (/c You seem tense. Take a deep breath and relax!);Start-
Sleep s 900) } while(1)
Which of the following BEST represents what the attacker was trying to accomplish?

• A. Taunt the user and then trigger a shutdown every 15 minutes.
• B. Taunt the user and then trigger a reboot every 15 minutes.
• C. Taunt the user and then trigger a shutdown every 900 minutes.
• D. Taunt the user and then trigger a reboot every 900 minutes.

Answer:

B

Question 3

A Linux system administrator found suspicious activity on host IP 192.168.10.121. This host is also
establishing a connection to IP 88.143.12.123. Which of the following commands should the
administrator use to capture only the traffic between the two hosts?

• A. # tcpdump -i eth0 host 88.143.12.123
• B. # tcpdump -i eth0 dst 88.143.12.123
• C. # tcpdump -i eth0 host 192.168.10.121
• D. # tcpdump -i eth0 src 88.143.12.123

Answer:

B

Question 4

After imaging a disk as part of an investigation, a forensics analyst wants to hash the image using a
tool that supports piecewise hashing. Which of the following tools should the analyst use?

• A. md5sum
• B. sha256sum
• C. md5deep
• D. hashdeep

Answer:

A

Question 5

Which of the following is a cybersecurity solution for insider threats to strengthen information
protection?

• A. Web proxy
• B. Data loss prevention (DLP)
• C. Anti-malware
• D. Intrusion detection system (IDS)

Answer:

B

Reference:
https://www.techrepublic.com/article/how-to-protect-your-organization-against-insider-threats/

Question 6

A security administrator is investigating a compromised host. Which of the following commands
could the investigator use to display executing processes in real time?

• A. ps
• B. top
• C. nice
• D. pstree

Answer:

B

Reference:
https://www.cyberciti.biz/faq/show-all-running-processes-in-linux/

Question 7

A system administrator identifies unusual network traffic from outside the local network. Which of
the following
is the BEST method for mitigating the threat?

• A. Malware scanning
• B. Port blocking
• C. Packet capturing
• D. Content filtering

Answer:

C

Question 8

Which of the following technologies would reduce the risk of a successful SQL injection attack?

• A. Reverse proxy
• B. Web application firewall
• C. Stateful firewall
• D. Web content filtering

Answer:

B

Reference:
http://www.enterprisenetworkingplanet.com/netsecur/article.php/3866756/10-Ways-to-Prevent-
or
- Mitigate-SQL-Injection-Attacks.htm

Question 9

An incident responder has collected network capture logs in a text file, separated by five or more
data fields.
Which of the following is the BEST command to use if the responder would like to print the file (to
terminal/ screen) in numerical order?

• A. cat | tac
• B. more
• C. sort –n
• D. less

Answer:

C

Reference:
https://kb.iu.edu/d/afjb

Question 10

Which of the following characteristics of a web proxy strengthens cybersecurity? (Choose two.)

• A. Increases browsing speed
• B. Filters unwanted content
• C. Limits direct connection to Internet
• D. Caches frequently-visited websites
• E. Decreases wide area network (WAN) traffic

Answer:

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