NEW QUESTION 1

Which of the following statements is true about residual risks?

• A. It is the probabilistic risk after implementing all security measures.
• B. It can be considered as an indicator of threats coupled with vulnerability.
• C. It is a weakness or lack of safeguard that can be exploited by a threat.
• D. It is the probabilistic risk before implementing all security measures.

Answer: A

Explanation:

The residual risk is the risk or danger of an action or an event, a method or a (technical) process that still conceives these dangers even if all theoretically possible safety measures would be applied. The formula to calculate residual risk is (inherent risk) x (control risk) where inherent risk is (threats vulnerability). Answer B is incorrect. In information security, security risks are considered as an indicator of threats coupled with vulnerability. In other words, security risk is a probabilistic function of a given threat agent exercising a particular vulnerability and the impact of that risk on the organization. Security risks can be mitigated by reviewing and taking responsible actions based on possible risks. Answer C is incorrect. Vulnerability is a weakness or lack of safeguard that can be exploited by a threat, thus causing harm to the information systems or networks. It can exist in hardware , operating systems, firmware, applications, and configuration files. Vulnerability has been variously defined in the current context as follows: 1.A security weakness in a Target of Evaluation due to failures in analysis, design, implementation, or operation and such. 2.Weakness in an information system or components (e.g. system security procedures, hardware design, or internal controls that could be exploited to produce an information-related misfortune.) 3.The existence of a weakness, design, or implementation error that can lead to an unexpected, undesirable event compromising the security of the system, network, application, or protocol involved.

NEW QUESTION 2

Which of the following statements is true about COLSPAN attribute?

• A. COLSPAN is used to create columns in a table.
• B. COLSPAN is used to divide one column into many columns.
• C. COLSPAN is used to span one column across many rows.
• D. COLSPAN is used to span one column across many columns.

Answer: D

Explanation:

COLSPAN attribute is used to span one column across many columns. COLSPAN is an attribute of <TD> and <TH> tags that allow a single column in a table to take space that is occupied by several columns. If the specified COLSPAN value is greater than the number of columns in the table, then a new column is created at the end of the row. Reference: MSDN, Contents: COLSPAN

NEW QUESTION 3

Which of the following is an example of penetration testing?

• A. Configuring firewall to block unauthorized traffic
• B. Implementing HIDS on a computer
• C. Simulating an actual attack on a network
• D. Implementing NIDS on a network

Answer: C

Explanation:

Penetration testing is a method of evaluating the security of a computer system or network by simulating an attack from a malicious source, known as a Black Hat Hacker, or Cracker. The process involves an active analysis of the system for any potential vulnerabilities that may result from poor or improper system configuration, known and/or unknown hardware or software flaws, or operational weaknesses in process or technical countermeasures. This analysis is carried out from the position of a potential attacker, and can involve active exploitation of security vulnerabilities. Any security issues that are found will be presented to the system owner together with an assessment of their impact and often with a proposal for mitigation or a technical solution. The intent of a penetration testing is to determine feasibility of an attack and the amount of business impact of a successful exploit, if discovered. It is a component of a full security of penetration testing.

NEW QUESTION 4

You are tasked with creating an ACL to apply to Fa0/0 based on the following requirements: The ACL must be protocol specific. All traffic from host 10.10.45.2 and subnet 10.10.1.32/27 must be denied access through the router. Telnet and SSH must be denied for ALL hosts except the management host with the IP address of 10.10.0.100. This management host must not only have Telnet and SSH access, but access to any port in the TCP and UDP suite to any destination. HTTP, HTTPS, and DNS requests must be allowed for all hosts on subnets 10.10.2.0/24 and 10.10.3.0/24 to any destination. All remaining traffic must be denied. Cisco IOS applies an implied deny all at the end of an ACL. However, you must provide this configuration manually so that engineers can see hit counts on the deny all traffic when running the show ip access-lists command. Which of the following sets of commands will you choose to complete the configuration on Router A?

• A. RouterA(config)#access-list 110 deny ip host 10.10.45.2 any RouterA(config)#access-list 110 deny ip 10.10.1.32 0.0.0.31 any RouterA(config)#access-list 110 permit tcp host 10.10.0.100 any RouterA(config)#access-list 110 permit udp host 10.10.0.100 any RouterA(config)#access-list 110 permit tcp 10.10.2.0 0.0.1.255 any eq 80RouterA(config)#access-list 110 permit tcp 10.10.2.0 0.0.1.255 any eq 443RouterA(config)#access-list 110 permit udp 10.10.2.0 0.0.1.255 any eq 53 RouterA(config)#access-list 110 deny ip any any RouterA(config)#interface fa0/0RouterA(config-if)#ip access-group 110 out
• B. RouterA(config)#access-list 110 deny ip host 10.10.45.2 any RouterA(config)#access-list 110 deny ip 10.10.1.32 0.0.0.31 any RouterA(config)#access-list 110 permit ip host 10.10.0.100 any RouterA(config)#access-list 110 permit tcp 10.10.2.0 0.0.1.255 any eq 80RouterA(config)#access-list 110 permit tcp 10.10.2.0 0.0.1.255 any eq 443RouterA(config)#access-list 110 permit udp 10.10.2.0 0.0.1.255 any eq 53 RouterA(config)#access-list 110 deny ip any any RouterA(config)#interface fa0/0 RouterA(config-if)#ip access-group 110 in
• C. RouterA(config)#access-list 110 deny ip host 10.10.45.2 any RouterA(config)#access-list 110 deny ip 10.10.1.32 0.0.0.31 any RouterA(config)#access-list 110 permit tcp host 10.10.0.100 any RouterA(config)#access-list 110 permit udp host 10.10.0.100 any RouterA(config)#access-list 110 permit tcp 10.10.2.0 0.0.1.255 any eq 80RouterA(config)#access-list 110 permit tcp 10.10.2.0 0.0.1.255 any eq 443RouterA(config)#access-list 110 permit udp 10.10.2.0 0.0.1.255 any eq 53 RouterA(config)#access-list 110 deny ip any any RouterA(config)#interface fa0/0 RouterA(config-if)#ip access-group 110 in
• D. RouterA(config)#access-list 99 deny ip host 10.10.45.2 any RouterA(config)#access-list 99 deny ip 10.10.1.32 0.0.0.31 any RouterA(config)#access-list 99 permit tcp host 10.10.0.100 any RouterA(config)#access-list 99 permit udp host 10.10.0.100 any RouterA(config)#access-list 99 permit tcp 10.10.2.0 0.0.1.255 any eq 80RouterA(config)#access-list 99 permit tcp 10.10.2.0 0.0.1.255 any eq 443RouterA(config)#access-list 99 permit udp 10.10.2.0 0.0.1.255 any eq 53 RouterA(config)#access-list 99 deny ip any any RouterA(config)#interface fa0/0 RouterA(config-if)#ip access-group 99 in

Answer: C

Explanation:

This ACL is an extended ACL. It meets the traffic requirements and is applied to Fa0/0 in the appropriate direction of in, which matches traffic going into the interface. In addition, this ACL meets the needs for subnets 10.10.2.0/24 and 10.10.3.0/24 by applying the subnet and wildcard mask of 10.10.2.0 0.0.1.255 for the lines that apply http, https, and dns. These subnets are covered by the wildcard mask 0.0.1.255. This wildcard mask is applied to a range of hosts from 10.10.2.0 through 10.10.3.255 which covers both of the subnets required. This is handy since both subnets are next to each other in their network numbers. Note: If the network numbers were not next to each other, for example 10.10.2.0/24 and 10.10.20.0/24, then the wildcard mask of 0.0.1.255 would be incorrect. A wildcard mask of 0.0.0.255 would be required. The configuration of the ACL would then be applied using the following commands: <!-- Only the relevant commands are displayed --> RouterA(config)#access-list 110 permit tcp 10.10.2.0 0.0.0.255 any eq 80
RouterA(config)#access-list 110 permit tcp 10.10.2.0 0.0.0.255 any eq 443
RouterA(config)#access-list 110 permit udp 10.10.2.0 0.0.0.255 any eq 53
RouterA(config)#access-list 110 permit tcp 10.10.20.0 0.0.0.255 any eq 80
RouterA(config)#access-list 110 permit tcp 10.10.20.0 0.0.0.255 any eq 443
RouterA(config)#access-list 110 permit udp 10.10.20.0 0.0.0.255 any eq 53

NEW QUESTION 5

In which of the following techniques does an attacker take network traffic coming towards a host at one port and forward it from that host to another host?

• A. Snooping
• B. UDP port scanning
• C. Firewalking
• D. Port redirection

Answer: D

Explanation:

Port redirection is a technique by which an attacker takes network traffic coming towards a host at one port and redirects it from that host to another host. For example, tools such as Fpipe and Datapipe are port redirection tools that accept connections at any specified port and resend them to other specified ports on specified hosts. For example, the following command establishes a listener on port 25 on the test system and then redirects the connection to port 80 on the target system using the source port of 25. C.\>fpipe -l 25 -s 25 -r 80 IP_address Answer C is incorrect. Firewalking is a technique for gathering information about a remote network protected by a firewall. This technique can be used effectively to perform information gathering attacks. In this technique, an attacker sends a crafted packet with a TTL value that is set to expire one hop past the firewall. If the firewall allows this crafted packet through, it forwards the packet to the next hop. On the next hop, the packet expires and elicits an ICMP "TTL expired in transit" message to the attacker. If the firewall does not allow the traffic, there should be no response, or an ICMP "administratively prohibited" message should be returned to the attacker. A malicious attacker can use firewalking to determine the types of ports/protocols that can bypass the firewall. To use firewalking, the attacker needs the IP address of the last known gateway before the firewall and the IP address of a host located behind the firewall. The main drawback of this technique is that if an administrator blocks ICMP packets from leaving the network, it is ineffective. Answer A is incorrect. Snooping is an activity of observing the content that appears on a computer monitor or watching what a user is typing. Snooping also occurs by using software programs to remotely monitor activity on a computer or network device. Hackers or attackers use snooping techniques and equipment such as keyloggers to monitor keystrokes, capture passwords and login information, and to intercept e-mail and other private communications. Sometimes, organizations also snoop their employees legitimately to monitor their use of organizations' computers and track Internet usage. Answer B is incorrect. In UDP port scanning, a UDP packet is sent to each port of the target system. If the remote port is closed, the server replies that the remote port is unreachable. If the remote Port is open, no such error is generated. Many firewalls block the TCP port scanning, at that time the UDP port scanning may be useful. Certain IDS and firewalls can detect UDP port scanning easily.

NEW QUESTION 6

Audit trail or audit log is a chronological sequence of audit records, each of which contains evidence directly pertaining to and resulting from the execution of a business process or system function. Under which of the following controls does audit control come?

• A. Protective controls
• B. Reactive controls
• C. Detective controls
• D. Preventive controls

Answer: C

Explanation:

Audit trail or audit log comes under detective controls. Detective controls are the audit controls that are not needed to be restricted. Any control that performs a monitoring activity can likely be defined as a Detective Control. For example, it is possible that mistakes, either intentional or unintentional, can be made. Therefore, an additional Protective control is that these companies must have their financial results audited by an independent Certified Public Accountant. The role of this accountant is to act as an auditor. In fact, any auditor acts as a Detective control. If the organization in question has not properly followed the rules, a diligent auditor should be able to detect the deficiency which indicates that some control somewhere has failed. Answer B is incorrect. Reactive or corrective controls typically work in response to a detective control, responding in such a way as to alert or otherwise correct an unacceptable condition. Using the example of account rules, either the internal Audit Committee or the SEC itself, based on the report generated by the external auditor, will take some corrective action. In this way, they are acting as a Corrective or Reactive control. Answer A, D are incorrect. Protective or preventative controls serve to proactively define and possibly enforce acceptable behaviors. As an example, a set of common accounting rules are defined and must be followed by any publicly traded company. Each quarter, any particular company must publicly state its current financial standing and accounting as reflected by an application of these rules. These accounting rules and the SEC requirements serve as protective or preventative controls.

NEW QUESTION 7

You work as a Java Programmer for JavaSkills Inc. You are working with the Linux operating system. Nowadays, when you start your computer, you notice that your OS is taking more time to boot than usual. You discuss this with your Network Administrator. He suggests that you mail him your Linux bootup report. Which of the following commands will you use to create the Linux bootup report?

• A. touch bootup_report.txt
• B. dmesg > bootup_report.txt
• C. dmesg | wc
• D. man touch

Answer: B

Explanation:

According to the scenario, you can use dmesg > bootup_report.txt to create the bootup file. With this command, the bootup messages will be displayed and will be redirected towards bootup_report.txt using the > command.

NEW QUESTION 8

With reference to the given case study, one of the security goals requires to configure a secure connection between the Boston distribution center and the headquarters. You want to implement IP filter to fulfill the security requirements. How should you implement IP filters at the headquarters? (Click the Exhibit button on the toolbar to see the case study.)

• A. Add source filters for the headquarters for UDP port 1701 and IP protocol 50.Add destination filters for the Boston distribution center for UDP port 1701 and IP protocol 50.
• B. Add source filters for the Boston distribution center for UDP port 80 and IP protocol 50. Add destination filters for headquarters for UDP port 80 and IP protocol 50.
• C. Add source filters for the headquarters for UDP port 80 and IP protocol 50.Add destination filters for the Boston distribution center for UDP port 80 and IP protocol 50.
• D. Add source filters for the Boston distribution center for UDP port 1701 and IP protocol 50.Add destination filters for the headquarters for UDP port 1701 and IP protocol 50.

Answer: D

Explanation:

To implement IP filters at the headquarters, add source filters for the Boston distribution center for UDP port 1701 and IP protocol 50. Also, add destination filters for the headquarters for UDP port 1701 and IP protocol 50. The Windows 2000 Router service provides routing services in the LAN and WAN environments, and over the Internet, using secure virtual private network (VPN) connections. The VPN connections are based on the Point-to-Point Tunneling Protocol (PPTP) and the Layer 2 Tunneling Protocol (L2TP) L2TP is very similar to PPTP but uses UDP, and therefore can be used over asynchronous transfer mode (ATM), Frame Relay, and X.25 networks as well. When L2TP is used over IP networks, it uses a UDP port 1701 packet format for both a control channel and a data channel. L2TP can also be used with IPSec to provide a fully secured network link. Further, IP packet filtering provides an ability to restrict the traffic into and out of each interface. Packet filtering is based on filters defined by the values of source and destination IP addresses, TCP, and UDP port numbers, and IP protocol numbers. Inbound filters that are
applied to the receiving traffic allow the receiving computer to match the traffic with the IP Filter List for the source IP address. Similarly, the outbound filters that are applied to the traffic leaving a computer towards a destination trigger a security negotiation for the destination IP address. That is why, to implement the IP filtering at the headquarters, you have to add a source address for the filters at the Boston center and a destination address for the filters at the headquarters.

NEW QUESTION 9

You work as a programmer for uCertify.Inc. You have a session object named session1 with an attribute named Attribute1, and an HttpSessionBindingEvent object binding1 bound to session1. Which of the following will be used to retrieve Attribute1?

• A. Object obj=binding1.getSession().getAttribute("Attribute1");
• B. Object obj=binding1.getAttribute("Attribute1");
• C. Long MyAttribute=session1.getAttribute("Attribute1");
• D. Object obj=session1.getAttribute("Attribute1");
• E. String str1=session1.getAttribute("Attribute1");

Answer: AD

Explanation:

The following two code are used to retrieve Attribute1: 1.Object obj=session1.getAttribute("Attribute1"); The getAttribute() method is used to retrieve the bound object with the specified name in this session, or null if no object is bound under the name. 2.Object obj=binding1.getSession().getAttribute("Attribute1"); The getSession() gets the current valid session associated with this request. a String object. Answer B is incorrect. The HttpSessionBindingEvent object cannot use the getAttribute() method.

NEW QUESTION 10

Samantha works as a Web Developer for XYZ CORP. She is designing a Web site for the company. In a Web page, she uses the HTTP-EQUIV attribute to control the page cache. Which of the following HTTP-EQUIV values controls the page cache in the browser folder?

• A. Window-target
• B. Status-code
• C. Content-type
• D. Pragma

Answer: D

Explanation:

HTTP-EQUIV is an attribute of the META tag. It sets or retrieves information used to bind the META tag's content to an HTTP response header. The pragma value of HTTP-EQUIV controls the page cache.

NEW QUESTION 11

This is a Windows-based tool that is used for the detection of wireless LANs using the IEEE 802.11a, 802.11b, and 802.11g standards. The main features of these tools are as follows: It displays the signal strength of a wireless network, MAC address, SSID, channel details, etc. It is commonly used for the following purposes: a.War driving b.Detecting unauthorized access pointsc.Detecting causes of interference on a WLAN d.WEP ICV error trackinge.Making Graphs and Alarms on 802.11 Data, including Signal Strength This tool is known as .

• A. THC-Scan
• B. NetStumbler
• C. Absinthe
• D. Kismet

Answer: B

Explanation:

NetStumbler is a Windows-based tool that is used for the detection of wireless LANs using the IEEE 802.11a, 802.11b, and 802.11g standards. The main features of NetStumbler are as follows: It displays the signal strength of a wireless network, MAC address, SSID, channel details, etc. It is commonly used for the following purposes: a.War driving b.Detecting unauthorized access points c.Detecting causes of interference on a WLAN d.WEP ICV error tracking e.Making Graphs and Alarms on 802.11 Data, including Signal Strength
Answer D is incorrect. Kismet is an IEEE 802.11 layer2 wireless network detector, sniffer, and intrusion detection system. Answer A is incorrect. THC-Scan is a war-dialing tool. Answer C is incorrect. Absinthe is an automated SQL injection tool.

NEW QUESTION 12

You have to ensure that your Cisco Router is only accessible via telnet and ssh from the following hosts and subnets: 10.10.2.103 10.10.0.0/24 Which of the following sets of commands will you use to accomplish the task?

• A. access-list 10 permit host 10.10.2.103access-list 10 permit 10.10.0.0 0.0.0.255access-list 10 deny any line vty 0 4 access-class 10 out
• B. access-list 10 permit 10.10.2.103access-list 10 permit 10.10.0.0 0.0.0.255access-list 10 deny any line vty 0 4 access-group 10 in
• C. access-list 10 permit host 10.10.2.103access-list 10 permit 10.10.0.0 0.0.0.255access-list 10 deny any line vty 0 4access-class 10 in
• D. access-list 10 permit host 10.10.2.103access-list 11 permit host 10.10.0.0 255.255.255.0access-list 12 deny any line vty 0 4access-group 10, 11, 12 in

Answer: C

Explanation:

In order to accomplish the task, you will have to run the following sets of commands: access-list 10 permit host 10.10.2.103 access-list 10 permit 10.10.0.0 0.0.0.255 access-list 10 deny any line vty 0 4 access-class 10 in This configuration set meets all the requirements. The ACL is correctly configured and is applied to the VTY lines using the access-class command for inbound connections. Answer D is incorrect. This
configuration actually creates 3 separate ACL's (10, 11, and 12) and also incorrectly attempts to apply the ACL's to the VTY lines. Answer A is incorrect. This configuration is correct except for the access-class command being applied in the outbound direction. When using "access-class out", the router will not match connections coming into the router for Telnet and/or SSH. Instead, it will match connections being generated from the router. Answer B is incorrect. This configuration is correct except for the access-group command. Access-group is used to apply ACLs to an interface. Access-class is used to apply ACLs to VTY lines.

NEW QUESTION 13

Victor works as a professional Ethical Hacker for SecureEnet Inc. He wants to scan the wireless network of the company. He uses a tool that is a free open-source utility for
network exploration. The tool uses raw IP packets to determine the following: What ports are open on our network systems. What hosts are available on the network. Identify unauthorized wireless access points. What services (application name and version) those hosts are offering. What operating systems (and OS versions) they are running. What type of packet filters/firewalls are in use. Which of the following tools is Victor using?

• A. Nessus
• B. Sniffer
• C. Nmap
• D. Kismet

Answer: C

Explanation:

Nmap is a free open-source utility for network exploration and security auditing. It is used to discover computers and services on a computer network, thus creating a "map" of the network. Just like many simple port scanners, Nmap is capable of discovering passive services. In addition, Nmap may be able to determine various details about the remote computers. These include operating system, device type, uptime, software product used to run a service, exact version number of that product, presence of some firewall techniques and, on a local area network, even vendor of the remote network card. Nmap runs on Linux, Microsoft Windows etc. Answer D is incorrect. Kismet is a Linux-based 802.11 wireless network sniffer and intrusion detection system. It can work with any wireless card that supports raw monitoring (rfmon) mode. Kismet can sniff 802.11b, 802.11a, 802.11g, and 802.11n traffic. Kismet can be used for the following tasks: To identify networks by passively collecting packets To detect standard named networks To detect masked networks To collect the presence of non-beaconing networks via data traffic Answer A is incorrect. Nessus is proprietary comprehensive vulnerability scanning software. It is free of charge for personal use in a non-enterprise environment. Its goal is to detect potential vulnerabilities on the tested systems. It is capable of checking various types of vulnerabilities, some of which are as follows: Vulnerabilities that allow a remote cracker to control or access sensitive data on a system. Misconfiguration (e.g. open mail relay, missing patches, etc). Default passwords, a few common passwords, and blank/absent passwords on some system accounts. Nessus can also call Hydra (an external tool) to launch a dictionary attack. Denials of service against the TCP/IP stack by using mangled packets. Answer B is incorrect. A sniffer is a software tool that is used to capture any network traffic. Since a sniffer changes the NIC of the LAN card into promiscuous mode, the NIC begins to record incoming and outgoing data traffic across the network. A sniffer attack is a passive attack because the attacker does not directly connect with the target host. This attack is most often used to grab logins and passwords from network traffic. Tools such as Ethereal, Snort, Windump, EtherPeek, Dsniff are some good examples of sniffers. These tools provide many facilities to users such as graphical user interface, traffic statistics graph, multiple sessions tracking, etc.

NEW QUESTION 14

Which of the following is an attempt to give false information or to deny that a real event or transaction should have occurred?

• A. A DDoS attack
• B. A repudiation attack
• C. A reply attack
• D. A dictionary attack

Answer: B

Explanation:

A repudiation attack is an attempt to give false information or to deny that a real event or transaction should have occurred. Answer A is incorrect. In a distributed denial of service (DDOS) attack, an attacker uses multiple computers throughout the network that has been previously infected. Such computers act as zombies and work together to send out bogus messages, thereby increasing the amount of phony traffic. The major advantages to an attacker of using a distributed denial-of-service attack are that multiple machines can generate more attack traffic than one machine, multiple attack machines are harder to turn off than one attack machine, and that the behavior of each attack machine can be stealthier, making it harder to track down and shut down. TFN, TRIN00, etc. are tools used for a DDoS attack. Answer C is incorrect. A replay attack is a type of attack in which attackers capture packets containing passwords or digital signatures whenever packets pass between two hosts on a network. In an attempt to obtain an authenticated connection, the attackers then resend the captured packet to the system. In this type of attack, the attacker does not know the actual password, but can simply replay
the captured packet. Answer D is incorrect. Dictionary attack is a type of password guessing attack. This type of attack uses a dictionary of common words to find out the password of a user. It can also use common words in either upper or lower case to find a password. There are many programs available on the Internet to automate and execute dictionary attacks.

NEW QUESTION 15

What will be the output of the following command? echo $(date %M) > date.txt

• A. The current time (Month) will be written in the date.txt file.
• B. It will create a variable $(date %M).
• C. It will print a string "date %M".
• D. The current time (Minutes) will be written in the date.txt file.

Answer: D

Explanation:

The date command with the %M specifier prints the current time (Minutes). Since the output is redirected towards the date.txt file, the current time (Minutes) will be printed in the date.txt file.

NEW QUESTION 16

Peter works as a Web Developer for XYZ CORP. He is developing a Web site for the company. Peter specifies MARGINHEIGHT="0" and MARGINWIDTH="0" in one of the Web pages. How will this affect the Web page?

• A. It will create a borderless page structure when viewed in any browser.
• B. It will create a borderless page structure when viewed in Netscape Navigator.
• C. It will delete all the text from the margins.
• D. It will create a borderless page structure when viewed in Internet Explorer.

Answer: B

Explanation:

The MARGINHEIGHT and MARGINWIDTH attributes are used in the <BODY> tag to adjust the top and left margins of a Web page to be displayed in Netscape Navigator. Specifying MARGINHEIGHT="0" and MARGINWIDTH="0" within the <BODY> tag will create a borderless page structure when viewed in Netscape Navigator. Answer D is incorrect. The TOPMARGIN and LEFTMARGIN attributes are used in the <BODY> tag to adjust the top and left margins of a Web page to be displayed in Internet Explorer. Specifying TOPMARGIN="0" and LEFTMARGIN="0" within the <BODY> tag will create a borderless page structure when viewed in Internet Explorer. Answer C is incorrect. These attributes are used to adjust margins and not to delete text from margins.

NEW QUESTION 17

In which of the following scanning techniques does a scanner connect to an FTP server and request that server to start data transfer to the third system?

• A. Xmas Tree scanning
• B. TCP FIN scanning
• C. TCP SYN scanning
• D. Bounce attack scanning

Answer: D

Explanation:

In the TCP FTP proxy (bounce attack) scanning, a scanner connects to an FTP server and requests that server to start data transfer to the third system. Now, the scanner uses the PORT FTP command to declare whether or not the data transfer process is listening to the target system at the certain port number. Then the scanner uses LIST FTP command to list the current directory. This result is sent over the server. If the data transfer is successful, it is clear that the port is open. If the port is closed, the attacker receives the connection refused ICMP error message. Answer A is incorrect. Xmas Tree scanning is just the opposite of null scanning. In Xmas Tree scanning, all packets are turned on. If the target port is open, the service running on the target port discards the packets without any reply. According to RFC 793, if the port is closed, the remote system replies with the RST packet. Active monitoring of all incoming packets can help system network administrators detect an Xmas Tree scan. Answer B is incorrect. TCP FIN scanning is a type of stealth scanning, through which the attacker sends a FIN packet to the target port. If the port is closed, the victim assumes that this packet was sent mistakenly by the attacker and sends the RST packet to the attacker. If the port is open, the FIN packet will be ignored and the port will drop that packet. TCP FIN scanning is useful only for identifying ports of non Windows operating system because Windows operating systems send only RST packets irrespective of whether the port is open or closed. Answer C is incorrect. TCP SYN scanning is also known as half-open scanning because in this a full TCP connection is never opened. The steps of TCP SYN scanning are as follows: 1.The attacker sends SYN packet to the target port. 2.If the port is open, the attacker receives SYN/ACK message. 3.Now the attacker breaks the connection by sending an RST packet. 4.If the RST packet is received, it indicates that the port is closed. This type of scanning is hard to trace because the attacker never establishes a full 3-way handshake connection and most sites do not create a log of incomplete TCP connections.

NEW QUESTION 18
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