Latest ECCouncil 312-50v8 Real Exam Download 541-550

QUESTION 541
Which of the following would be the best reason for sending a single SMTP message to an address that does not exist within the target company?
A. To create a denial of service attack.
B. To verify information about the mail administrator and his address.
C. To gather information about internal hosts used in email treatment.
D. To gather information about procedures that are in place to deal with such messages.
Answer: 
The replay from the email server that states that there is no such recipient will also give you some information about the name of the email server, versions used and so on.
QUESTION 542
You are conducting a port scan on a subnet that has ICMP blocked. You have discovered 23 live systems and after scanning each of them you notice that they all show port 21 in closed state.
What should be the next logical step that should be performed?
A. Connect to open ports to discover applications.
B. Perform a ping sweep to identify any additional systems that might be up.
C. Perform a SYN scan on port 21 to identify any additional systems that might be up.
D. Rescan every computer to verify the results.
Answer: 
As ICMP is blocked youoll have trouble determining which computers are up and running by using a ping sweep. As all the 23 computers that you had discovered earlier had port 21 closed,probably any additional,previously unknown,systems will also have port 21 closed. By running a SYN scan on port 21 over the target network you might get replies from additional systems.
QUESTION 543
Ann would like to perform a reliable scan against a remote target. She is not concerned about being stealth at this point.
Which of the following type of scans would be the most accurate and reliable option?
A. A half-scan
B. A UDP scan
C. A TCP Connect scan
D. A FIN scan
Answer: 
A TCP Connect scan,named after the Unix connect() system call is the most accurate scanning method. If a port is open the operating system completes the TCP three-way handshake,and the port scanner immediately closes the connection. Otherwise an error code is returned. Example of a three-way handshake followed by a reset:
SourceDestinationSummary
[192.168.0.8][192.168.0.10]TCP: D=80 S=49389 SYN SEQ=3362197786 LEN=0 WIN=5840
[192.168.0.10] [192.168.0.8] TCP: D=49389 S=80 SYN ACK=3362197787 SEQ=58695210 LEN=0 WIN=65535 [192.168.0.8][192.168.0.10]TCP: D=80 S=49389 ACK=58695211 WIN<<2=5840 [192.168.0.8][192.168.0.10]TCP: D=80 S=49389 RST ACK=58695211 WIN<<2=5840
QUESTION 544
What type of port scan is shown below?
clip_image002
A. Idle Scan
B. Windows Scan
C. XMAS Scan
D. SYN Stealth Scan
Answer: 
An Xmas port scan is variant of TCP port scan. This type of scan tries to obtain information about the state of a target port by sending a packet which has multiple TCP flags set to 1 – “lit as an Xmas tree”. The flags set for Xmas scan are FIN,URG and PSH. The purpose is to confuse and bypass simple firewalls. Some stateless firewalls only check against security policy those packets which have the SYN flag set (that is,packets that initiate connection according to the standards). Since Xmas scan packets are different,they can pass through these simple systems and reach the target host.
QUESTION 545
War dialing is a very old attack and depicted in movies that were made years ago.
Why would a modem security tester consider using such an old technique?
A. It is cool,and if it works in the movies it must work in real life.
B. It allows circumvention of protection mechanisms by being on the internal network.
C. It allows circumvention of the company PBX.
D. A good security tester would not use such a derelict technique.
Answer: 
If you are lucky and find a modem that answers and is connected to the target network,it usually is less protected (as only employees are supposed to know of its existence) and once connected you donot need to take evasive actions towards any firewalls or IDS.
QUESTION 546
You are scanning into the target network for the first time. You find very few conventional ports open. When you attempt to perform traditional service identification by connecting to the open ports, it yields either unreliable or no results. You are unsure of which protocols are being used. You need to discover as many different protocols as possible.
Which kind of scan would you use to achieve this? (Choose the best answer)
A. Nessus scan with TCP based pings.
B. Nmap scan with the ɃsP (Ping scan) switch.
C. Netcat scan with the Ƀu Ƀe switches.
D. Nmap with the ɃsO (Raw IP packets) switch.
Answer: 
Running Nmap with the ɃsO switch will do a IP Protocol Scan. The IP protocol scan is a bit different than the other nmap scans. The IP protocol scan is searching for additional IP protocols in use by the remote station,such as ICMP,TCP,and UDP. If a router is scanned,additional IP protocols such as EGP or IGP may be identified.
QUESTION 547
What are two types of ICMP code used when using the ping command?
A. It uses types 0 and 8.
B. It uses types 13 and 14.
C. It uses types 15 and 17.
D. The ping command does not use ICMP but uses UDP.
Answer: 
ICMP Type 0 = Echo Reply,ICMP Type 8 = Echo
QUESTION 548
You are having problems while retrieving results after performing port scanning during internal testing. You verify that there are no security devices between you and the target system. When both stealth and connect scanning do not work, you decide to perform a NULL scan with NMAP. The first few systems scanned shows all ports open.
Which one of the following statements is probably true?
A. The systems have all ports open.
B. The systems are running a host based IDS.
C. The systems are web servers.
D. The systems are running Windows.
Answer: 
The null scan turns off all flags,creating a lack of TCP flags that should never occur in the real world. If the port is closed,a RST frame should be returned and a null scan to an open port results in no response. Unfortunately Microsoft (like usual) decided to completelyignore the standard and do things their own way. Thus this scan type will not work against systems running Windows as they choose not to response at all. This is a good way to distinguish that the system being scanned is running Microsoft Windows.
QUESTION 549
John has scanned the web server with NMAP. However, he could not gather enough information to help him identify the operating system running on the remote host accurately.
What would you suggest to John to help identify the OS that is being used on the remote web server?
A. Connect to the web server with a browser and look at the web page.
B. Connect to the web server with an FTP client.
C. Telnet to port 8080 on the web server and look at the default page code.
D. Telnet to an open port and grab the banner.
Answer: 
Most people donot care about changing the banners presented by applications listening to open ports and therefore you should get fairly accurate information when grabbing banners from open ports with,for example,a telnet application.
QUESTION 550
An Nmap scan shows the following open ports, and nmap also reports that the OS guessing results to match too many signatures hence it cannot reliably be identified:
21 ftp
23 telnet
80 http
443 https
What does this suggest?
A. This is a Windows Domain Controller
B. The host is not firewalled
C. The host is not a Linux or Solaris system
D. The host is not properly patched
Answer: 
If the answer was A nmap would guess it,it holds the MS signature database,the host not being firewalled makes no difference.The host is not linux or solaris,well it very well could be. The host is not properly patched? That is the closest; nmaps OS detection architecture is based solely off the TCP ISN issued by the operating systems TCP/IP stack,if the stack is modified to show output from randomized ISN’s or if your using a program to change the ISN then OS detection will fail. If the TCP/IP IP ID’s are modified then os detection could also fail,because the machine would most likely come back as being down.

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