Last Updated on September 20, 2021 by Admin 2

312-38 : Certified Network Defender : Part 02

  1. Which of the following is a distributed multi-access network that helps in supporting integrated communications using a dual bus and distributed queuing?

    • Logical Link Control
    • Token Ring network
    • Distributed-queue dual-bus
    • CSMA/CA
    Explanation:
    In telecommunication, a distributed-queue dual-bus network (DQDB) is a distributed multi-access network that helps in supporting integrated communications using a dual bus and distributed queuing, providing access to local or metropolitan area networks, and supporting connectionless data transfer, connection-oriented data transfer, and isochronous communications, such as voice communications. IEEE 802.6 is an example of a network providing DQDB access methods. Answer option B is incorrect. A Token Ring network is a local area network (LAN) in which all computers are connected in a ring or star topology and a bit- or token-passing scheme is used in order to prevent the collision of data between two computers that want to send messages at the same time. The Token Ring protocol is the second most widely-used protocol on local area networks after Ethernet. The IBM Token Ring protocol led to a standard version, specified as IEEE 802.5. Both protocols are used and are very similar. The IEEE 802.5 Token Ring technology provides for data transfer rates of either 4 or 16 megabits per second.
    Answer option A is incorrect. The IEEE 802.2 standard defines Logical Link Control (LLC). LLC is the upper portion of the data link layer for local area networks.
    Answer option D is incorrect. Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) is an access method used by wireless networks (IEEE 802.11). In this method, a device or computer that transmits data needs to first listen to the channel for an amount of time to check for any activity on the channel. If the channel is sensed as idle, the device is allowed to transmit data. If the channel is busy, the device postpones its transmission. Once the channel is clear, the device sends a signal telling all other devices not to transmit data, and then sends its packets. In Ethernet (IEEE 802.3) networks that use CSMA/CD, the device or computer continues to wait for a time and checks if the channel is still free. If the channel is free, the device transmits packets and waits for an acknowledgment signal indicating that the packets were received.
  2. Which of the following is a distributed application architecture that partitions tasks or workloads between service providers and service requesters? Each correct answer represents a complete solution. Choose all that apply.

    • Client-server computing
    • Peer-to-peer (P2P) computing
    • Client-server networking
    • Peer-to-peer networking
    Explanation:
    Client-server networking is also known as client-server computing. It is a distributed application architecture that partitions tasks or workloads between service providers (servers) and service requesters, called clients. Often clients and servers operate over a computer network on separate hardware. A server machine is a high-performance host that is running one or more server programs which share its resources with clients. A client does not share any of its resources, but requests a server’s content or service function. Clients therefore initiate
    communication sessions with servers which await (listen to) incoming requests.
    Answer options D and B are incorrect. Peer-to-peer (P2P) computing or networking is a distributed application architecture that partitions tasks or workloads between peers. Peers are equally privileged, equipotent participants in the application. They are said to form a peer-to-peer network of nodes. Peer-to-peer networking (also known simply as peer networking) differs from client-server networking, where certain devices have the responsibility to provide or “serve” data, and other devices consume or otherwise act as “clients” of those servers.
  3. Which of the following is an attack on a website that changes the visual appearance of the site and seriously damages the trust and reputation of the website?

    • Website defacement
    • Zero-day attack
    • Spoofing
    • Buffer overflow
    Explanation:
    Website defacement is an attack on a website that changes the visual appearance of the site. These are typically the work of system crackers, who break into a Web server and replace the hosted website with one of their own. Sometimes, the Defacer makes fun of the system administrator for failing to maintain server security. Most times, the defacement is harmless; however, it can sometimes be used as a distraction to cover up more sinister actions such as uploading malware.
    A high-profile website defacement was carried out on the website of the company SCO Group following its assertion that Linux contained stolen code. The title of the page was changed from Red Hat vs. SCO to SCO vs. World with various satirical content.
    Answer option D is incorrect. Buffer overflow is a condition in which an application receives more data than it is configured to accept. This usually occurs due to programming errors in the application. Buffer overflow can terminate or crash the application.
    Answer option B is incorrect. A zero-day attack, also known as zero-hour attack, is a computer threat that tries to exploit computer application vulnerabilities which are unknown to others, undisclosed to the software vendor, or for which no security fix is available. Zero-day exploits (actual code that can use a security hole to carry out an attack) are used or shared by attackers before the software vendor knows about the vulnerability. User awareness training is the most effective technique to mitigate such attacks.
    Answer option C is incorrect. Spoofing is a technique that makes a transmission appear to have come from an authentic source by forging the IP address, email address, caller ID, etc. In IP spoofing, a hacker modifies packet headers by using someone else’s IP address to hide his identity. However, spoofing cannot be used while surfing the Internet, chatting on-line, etc. because forging the source IP address causes the responses to be misdirected.
  4. Which of the following cables is made of glass or plastic and transmits signals in the form of light?

    • Coaxial cable
    • Twisted pair cable
    • Plenum cable
    • Fiber optic cable
    Explanation:
    Fiber optic cable is also known as optical fiber. It is made of glass or plastic and transmits signals in the form of light. It is of cylindrical shape and consists of three concentric sections: the core, the cladding, and the jacket. Optical fiber carries much more information than conventional copper wire and is in general not subject to electromagnetic interference and the need to retransmit signals. Most telephone company’s long-distance lines are now made of optical fiber. Transmission over an optical fiber cable requires repeaters at distance intervals. The glass fiber requires more protection within an outer cable than copper.
    Answer option B is incorrect. Twisted pair cabling is a type of wiring in which two conductors (the forward and return conductors of a single circuit) are twisted together for the purposes of canceling out electromagnetic interference (EMI) from external sources. It consists of the following twisted pair cables:
    Shielded Twisted Pair: Shielded Twisted Pair (STP) is a special kind of copper telephone wiring used in some business installations. An outer covering or shield is added to the ordinary twisted pair telephone wires; the shield functions as a ground. Twisted pair is the ordinary copper wire that connects home and many business computers to the telephone company. Shielded twisted pair is often used in business installations. Unshielded Twisted Pair: Unshielded Twisted Pair (UTP) is the ordinary wire used in home. UTP cable is also the most common cable used in computer networking. Ethernet, the most common data networking standard, utilizes UTP cables. Twisted pair cabling is often used in data networks for short and medium length connections because of its relatively lower costs compared to optical fiber and coaxial cable.UTP is also finding increasing use in video applications, primarily in security cameras. Many middle to high-end cameras include a UTP output with setscrew terminals. This is made possible by the fact that UTP cable bandwidth has improved to match the baseband of television signals.
    Answer option A is incorrect. Coaxial cable is the kind of copper cable used by cable TV companies between the community antenna and user homes and businesses. Coaxial cable is sometimes used by telephone companies from their central office to the telephone poles near users. It is also widely installed for use in business and corporation Ethernet and other types of local area network. Coaxial cable is called “coaxial” because it includes one physical channel that carries the signal surrounded (after a layer of insulation) by another concentric physical channel, both running along the same axis. The outer channel serves as a ground. Many of these cables or pairs of coaxial tubes can be placed in a single outer sheathing and, with repeaters, can carry information for a great distance. It is shown in the figure below:
    312-38 Part 02 Q04 005
    312-38 Part 02 Q04 005

    Answer option C is incorrect. Plenum cable is cable that is laid in the plenum spaces of buildings. The plenum is the space that can facilitate air circulation for heating and air conditioning systems, by providing pathways for either heated/conditioned or return airflows. Space between the structural ceiling and the dropped ceiling or under a raised floor is typically considered plenum. However, some drop ceiling designs create a tight seal that does not allow for airflow and therefore may not be considered a plenum air-handling space. The plenum space is typically used to house the communication cables for the building’s computer and telephone network.

  5. Which of the following is a network that supports mobile communications across an arbitrary number of wireless LANs and satellite coverage areas?

    • LAN
    • WAN
    • GAN
    • HAN
    Explanation:
    A global area network (GAN) is a network that is used for supporting mobile communications across an arbitrary number of wireless LANs, satellite coverage areas, etc. The key challenge in mobile communications is handing off the user communications from one local coverage area to the next.
    Answer option B is incorrect. A wide area network (WAN) is a geographically dispersed telecommunications network. The term distinguishes a broader telecommunication structure from a local area network (LAN). A wide area network may be privately owned or rented, but the term usually connotes the inclusion of public (shared user) networks. An intermediate form of network in terms of geography is a metropolitan area network (MAN). A wide area network is also defined as a network of networks, as it interconnects LANs over a wide geographical area.
    Answer option D is incorrect. A home area network (HAN) is a residential LAN that is used for communication between digital devices typically deployed in the home, usually a small number of personal computers and accessories, such as printers and mobile computing devices.
    Answer option A is incorrect. The Local Area Network (LAN) is a group of computers connected within a restricted geographic area, such as residence, educational institute, research lab, and various other organizations. It allows the users to share files and services, and is commonly used for intra-office communication. The LAN has connections with other LANs via leased lines, leased services, or by tunneling across the Internet using the virtual private network technologies.
  6. FILL BLANK

    Fill in the blank with the appropriate term. A ______________________ network is a local area network (LAN) in which all computers are connected in a ring or star topology and a bit- or token-passing scheme is used for preventing the collision of data between two computers that want to send messages at the same time.

    • Token Ring
    Explanation:
    A Token Ring network is a local area network (LAN) in which all computers are connected in a ring or star topology and a bit- or token-passing scheme is used in order to prevent the collision of data between two computers that want to send messages at the same time. The Token Ring protocol is the second most widely-used protocol on local area networks after Ethernet. The IBM Token Ring protocol led to a standard version, specified as IEEE 802.5. Both protocols are used and are very similar. The IEEE 802.5 Token Ring technology provides for data transfer rates of either 4 or 16 megabits per second.
    Working:
    Empty information frames are constantly circulated on the ring. When a computer has a message to send, it adds a token to an empty frame and adds a message and a destination identifier to the frame. The frame is then observed by each successive workstation. If the workstation sees that it is the destination for the message, it copies the message from the frame and modifies the token back to 0. When the frame gets back to the originator, it sees that the token has been modified to 0 and that the message has been copied and received. It removes the message from the particular frame. The frame continues to circulate as an empty frame, ready to be taken by a workstation when it has a message to send.
  7. Which of the following techniques is used for drawing symbols in public places for advertising an open Wi-Fi wireless network?

    • Spamming
    • War driving
    • War dialing
    • Warchalking
    Explanation:
    Warchalking is the drawing of symbols in public places to advertise an open Wi-Fi wireless network. Having found a Wi-Fi node, the warchalker draws a special symbol on a nearby object, such as a wall, the pavement, or a lamp post. The name warchalking is derived from the cracker terms war dialing and war driving.
    Answer option B is incorrect. War driving, also called access point mapping, is the act of locating and possibly exploiting connections to wireless local area networks while driving around a city or elsewhere. To do war driving, one needs a vehicle, a computer (which can be a laptop), a wireless Ethernet card set to work in promiscuous mode, and some kind of an antenna which can be mounted on top of or positioned inside the car. Because a wireless LAN may have a range that extends beyond an office building, an outside user may be able to intrude into the network, obtain a free Internet connection, and possibly gain access to company records and other resources.
    Answer option C is incorrect. War dialing is a technique of using a modem to automatically scan a list of telephone numbers, usually dialing every number in a local area code to search for computers, BBS systems, and fax machines. Hackers use the resulting lists for various purposes, hobbyists for exploration, and crackers (hackers that specialize in computer security) for password guessing.
    Answer option A is incorrect. Spamming is the technique of flooding the Internet with a number of copies of the same message. The most widely recognized form of spams are e-mail spam, instant messaging spam, Usenet newsgroup spam, Web search engine spam, spam in blogs, online classified ads spam, mobile phone messaging spam, Internet forum spam, junk fax transmissions, social networking spam, television advertising and file sharing network spam.
  8. Which of the following is a standard protocol for interfacing external application software with an information server, commonly a Web server?

    • DHCP
    • IP
    • CGI
    • TCP
    Explanation:
    The Common Gateway Interface (CGI) is a standard protocol for interfacing external application software with an information server, commonly a Web server. The task of such an information server is to respond to requests (in the case of web servers, requests from client web browsers) by returning output. When a user requests the name of an entry, the server will retrieve the source of that entry’s page (if one exists), transform it into HTML, and send the result.
    Answer option A is incorrect. DHCP is a Dynamic Host Configuration Protocol that allocates unique (IP) addresses dynamically so that they can be used when no longer needed. A DHCP server is set up in a DHCP environment with the appropriate configuration parameters for the given network. The key parameters include the range or “pool” of available IP addresses, correct subnet masks, gateway, and name server addresses.
    Answer option B is incorrect. The Internet Protocol (IP) is a protocol used for communicating data across a packet-switched inter-network using the Internet Protocol Suite, also referred to as TCP/IP.IP is the primary protocol in the Internet Layer of the Internet Protocol Suite and has the task of delivering distinguished protocol datagrams (packets) from the source host to the destination host solely based on their addresses. For this purpose, the Internet Protocol defines addressing methods and structures for datagram encapsulation. The first major version of addressing structure, now referred to as Internet Protocol Version 4 (IPv4), is still the dominant protocol of the Internet, although the successor, Internet Protocol Version 6 (IPv6), is being deployed actively worldwide.
    Answer option D is incorrect. Transmission Control Protocol (TCP) is a reliable, connection-oriented protocol operating at the transport layer of the OSI model. It provides a reliable packet delivery service encapsulated within the Internet Protocol (IP). TCP guarantees the delivery of packets, ensures proper sequencing of data, and provides a checksum feature that validates both the packet header and its data for accuracy. If the network corrupts or loses a TCP packet during transmission, TCP is responsible for retransmitting the faulty packet. It can transmit large amounts of data. Application layer protocols, such as HTTP and FTP, utilize the services of TCP to transfer files between clients and servers.
  9. Which of the following honeypots provides an attacker access to the real operating system without any restriction and collects a vast amount of information about the attacker?

    • High-interaction honeypot
    • Medium-interaction honeypot
    • Honeyd
    • Low-interaction honeypot
    Explanation:
    A high-interaction honeypot offers a vast amount of information about attackers. It provides an attacker access to the real operating system without any restriction. A high-interaction honeypot is a powerful weapon that provides opportunities to discover new tools, to identify new vulnerabilities in the operating system, and to learn how blackhats communicate with one another.
    Answer option D is incorrect. A low-interaction honeypot captures limited amounts of information that are mainly transactional data and some limited interactive information. Because of simple design and basic functionality, low-interaction honeypots are easy to install, deploy, maintain, and configure. A low-interaction honeypot detects unauthorized scans or unauthorized connection attempts. A low-interaction honeypot is like a one-way connection, as the honeypot provides services that are limited to listening ports. Its role is very passive and does not alter any traffic. It generates logs or alerts when incoming packets match their patterns.
    Answer option B is incorrect. A medium-interaction honeypot offers richer interaction capabilities than a low-interaction honeypot, but does not provide any real underlying operating system target. Installing and configuring a medium-interaction honeypot takes more time than a low-interaction honeypot. It is also more complicated to deploy and maintain as compared to a low-interaction honeypot. A medium-interaction honeypot captures a greater amount of information but comes with greater risk. Answer option C is incorrect. Honeyd is an example of a low-interaction honeypot.
  10. Which of the following representatives of the incident response team takes forensic backups of systems that are the focus of an incident?

    • Technical representative
    • Lead investigator
    • Information security representative
    • Legal representative
    Explanation:
    A technical representative creates forensic backups of systems that are the focus of an incident and provides valuable information about the configuration of the network and target system.
    Answer option B is incorrect. A lead investigator acts as the manager of the computer security incident response team.
    Answer option D is incorrect. The legal representative looks after legal issues and ensures that the investigation process does not break any law.
    Answer option C is incorrect. The information security representative informs about the security safeguards that may affect their ability to respond to the incident.
  11. Which of the following devices allows wireless communication devices to connect to a wireless network using Wi-Fi, Bluetooth, or related standards?

    • Express card
    • WAP
    • WNIC
    • Wireless repeater
    • None
    Explanation:
    A wireless access point (WAP) is a device that allows wireless communication devices to connect to a wireless network using Wi-Fi, Bluetooth, or related standards. The WAP usually connects to a wired network, and it can transmit data between wireless devices and wired devices on the network. Each access point can serve multiple users within a defined network area. As people move beyond the range of one access point, they are automatically handed over to the next one. A small WLAN requires a single access point. The number of access points in a network depends on the number of network users and the physical size of the network.
    Answer option C is incorrect. A wireless network interface card (WNIC) is a network card that connects to a radio-based computer network, unlike a regular network interface controller (NIC) that connects to a wire-based network such as token ring or ethernet. A WNIC, just like a NIC, works on the Layer 1 and Layer 2 of the OSI Model. A WNIC is an essential component for wireless desktop computer. This card uses an antenna to communicate through microwaves. A WNIC in a desktop computer is usually connected using the PCI bus.
    Answer option A is incorrect. ExpressCard, a new standard introduced by PCMCIA, is a thinner, faster, and lighter modular expansion for desktops and laptops. Users can add memory, wired or wireless communication cards, and security devices by inserting these modules into their computers. ExpressCard slots are designed to accommodate modules that use either Universal Serial Bus (USB) 2.0 or the PCI Express standard. ExpressCard modules are available in two sizes, i.e., 34 mm wide (ExpressCard/34) and 54 mm wide (ExpressCard/54). Both modules are 75 mm long and 5 mm high. An ExpressCard/34 module can be inserted in either a 54 mm slot or a 34 mm slot, but an ExpressCard/54 requires a Universal (54 mm) slot. However, an extender can be used with ExpressCard/34 slot to connect the ExpressCard/54 module from outside of the computer. Both the modules are identical in performance. They take full advantage of the features of the PCI Express or USB 2.0 interfaces. The only difference between them is that the ExpressCard/54 form-factor, due to its larger surface area, allows for greater thermal dissipation than does an ExpressCard/34. As the performance does not vary with module size, module developers usually prefer to fit their applications into the smaller ExpressCard/34 form factor. But some applications, such as SmartCard readers, and CompactFlash readers, require the extra width of an ExpressCard/54 module.
    Answer option D is incorrect. A wireless repeater is a networking device that works as a repeater between a wireless router and computers. It is used to connect a client to the network when the client is out of the service area of the access point. If the wireless repeater is configured properly, it extends the range of the wireless LAN network.
  12. Which of the following protocols uses a control channel over TCP and a GRE tunnel operating to encapsulate PPP packets?

    • PPTP
    • ESP
    • LWAPP
    • SSTP
    Explanation:
    The Point-to-Point Tunneling Protocol (PPTP) is a method for implementing virtual private networks. PPTP uses a control channel over TCP and a GRE tunnel operating to encapsulate PPP packets. The PPTP specification does not describe encryption or authentication features and relies on the PPP protocol being tunneled to implement security functionality. However, the most common PPTP implementation, shipping with the Microsoft Windows product families, implements various levels of authentication and encryption natively as standard features of the Windows PPTP stack. The intended use of this protocol is to provide similar levels of security and remote access as typical VPN products.
    Answer option B is incorrect. Encapsulating Security Payload (ESP) is an IPSec protocol that provides confidentiality, in addition to authentication, integrity, and anti-replay. ESP can be used alone or in combination with Authentication Header (AH). It can also be nested with the Layer Two Tunneling Protocol (L2TP). ESP does not sign the entire packet unless it is being tunneled. Usually, only the data payload is protected, not the IP header.
    Answer option D is incorrect. Secure Socket Tunneling Protocol (SSTP) is a form of VPN tunnel that provides a mechanism to transport PPP or L2TP traffic through an SSL 3.0 channel. SSL provides transport-level security with key-negotiation, encryption, and traffic integrity checking. The use of SSL over TCP port 443 allows SSTP to pass through virtually all firewalls and proxy servers. SSTP servers must be authenticated during the SSL phase. SSTP clients can optionally be authenticated during the SSL phase, and must be authenticated in the PPP phase. The use of PPP allows support for common authentication methods, such as EAP-TLS and MS-CHAP. SSTP is available in Windows Server 2008, Windows Vista SP1, and later operating systems. It is fully integrated with the RRAS architecture in these operating systems, allowing its use with Winlogon or smart card authentication, remote access policies, and the Windows VPN client.
    Answer option C is incorrect. LWAPP (Lightweight Access Point Protocol) is a protocol used to control multiple Wi-Fi wireless access points at once. This can reduce the amount of time spent on configuring, monitoring, or troubleshooting a large network. This also allows network administrators to closely analyze the network.
  13. Which of the following procedures is designed to enable security personnel to identify, mitigate, and recover from malicious computer incidents, such as unauthorized access to a system or data, denial-of-service, or unauthorized changes to system hardware, software, or data?

    • Cyber Incident Response Plan
    • Crisis Communication Plan
    • Disaster Recovery Plan
    • Occupant Emergency Plan
    Explanation:
    The Cyber Incident Response Plan is used to address cyber attacks against an organization’s IT system through various procedures. These procedures enable security personnel to identify, mitigate, and recover from malicious computer incidents, such as denial-of-service attacks, unauthorized accessing of a system or data, or unauthorized changes to system hardware, software, or data.
    Answer option C is incorrect. A disaster recovery plan should contain data, hardware, and software that can be critical for a business. It should also include the plan for sudden loss such as hard disc crash. The business should use backup and data recovery utilities to limit the loss of data.
    Answer option D is incorrect. The Occupant Emergency Plan (OEP) is used to reduce the risk to personnel, property, and other assets while minimizing work disorders in the event of an emergency. It is the response procedure for occupants of a facility on the occurrence of a situation, which is posing a potential threat to the health and safety of personnel, the environment, or property. OEPs are developed at the facility level, specific to the geographic site and structural design of the building.
    Answer option B is incorrect. The crisis communication plan can be broadly defined as the plan for the exchange of information before, during, or after a crisis event. It is considered as a sub-specialty of the public relations profession that is designed to protect and defend an individual, company, or organization facing a public challenge to its reputation. The aim of crisis communication plan is to assist organizations to achieve continuity of critical business processes and information flows under crisis, disaster or event driven circumstances.
  14. Which of the following TCP commands are used to allocate a receiving buffer associated with the specified connection?

    • Send
    • Close
    • None
    • Receive
    • Interrupt
    Explanation:
    The Receive command is used to allocate a receiving buffer associated with the specified connection. An error is returned if no OPEN precedes this command or the calling process is not authorized to use this connection.
    Answer option A is incorrect. The Send command causes the data contained in the indicated user buffer to be sent to the indicated connection.
    Answer option C is incorrect. The Abort command causes all pending SENDs and RECEIVES to be aborted.
    Answer option B is incorrect. The Close command causes the connection specified to be closed.
  15. You work as a professional Computer Hacking Forensic Investigator for DataEnet Inc. You want to investigate e-mail information of an employee of the company. The suspected employee is using an online e-mail system such as Hotmail or Yahoo. Which of the following folders on the local computer will you review to accomplish the task? Each correct answer represents a complete solution. Choose all that apply.

    • History folder
    • Temporary Internet Folder
    • Cookies folder
    • Download folder
    Explanation:
    Online e-mail systems such as Hotmail and Yahoo leave files containing e-mail message information on the local computer. These files are stored in a number of folders, which are as follows:
    Cookies folder
    Temp folder
    History folder
    Cache folder
    Temporary Internet Folder Forensic tools can recover these folders for the respective e-mail clients. When folders are retrieved, e-mail files can be accessed. If the data is not readable, various tools are available to decrypt the information such as a cookie reader used with cookies.
    Answer option D is incorrect. Download folder does not contain any e-mail message information.
  16. Which of the following layers of the TCP/IP model maintains data integrity by ensuring that messages are delivered in the order in which they are sent and that there is no loss or duplication?

    • Transport layer
    • Link layer
    • Internet layer
    • Application layer
    Explanation:
    The transport layer ensures that messages are delivered in the order in which they are sent and that there is no loss or duplication. Transport layer maintains data integrity.
    Answer option C is incorrect. The Internet Layer of the TCP/IP model solves the problem of sending packets across one or more networks. Internetworking requires sending data from the source network to the destination network. This process is called routing. IP can carry data for a number of different upper layer protocols.
    Answer option B is incorrect. The Link Layer of TCP/IP model is the networking scope of the local network connection to which a host is attached. This is the lowest component layer of the Internet protocols, as TCP/IP is designed to be hardware independent. As a result, TCP/IP has been implemented on top of virtually any hardware networking technology in existence. The Link Layer is used to move packets between the Internet Layer interfaces of two different hosts on the same link. The processes of transmitting and receiving packets on a given link can be controlled both in the software device driver for the network card, as well as on firmware or specialized chipsets.
    Answer option D is incorrect. The Application Layer of TCP/IP model refers to the higher-level protocols used by most applications for network communication. Examples of application layer protocols include the File Transfer Protocol (FTP) and the Simple Mail Transfer Protocol (SMTP). Data coded according to application layer protocols are then encapsulated into one or more transport layer protocols, which in turn use lower layer protocols to affect actual data transfer.
  17. Which of the following is a telecommunication service designed for cost-efficient data transmission for intermittent traffic between local area networks (LANs) and between end-points in a wide area network (WAN)?

    • PPP
    • Frame relay
    • ISDN
    • X.25
    • None
    Explanation:
    Frame relay is a telecommunication service designed for cost-efficient data transmission for intermittent traffic between local area networks (LANs) and between end-points in a wide area network (WAN). Frame relay puts data in a variable-size unit called a frame. It checks for lesser errors as compared to other traditional forms of packet switching and hence speeds up data transmission. When an error is detected in a frame, it is simply dropped. The end points are responsible for detecting and retransmitting dropped frames.
    Answer option C is incorrect. Integrated Services Digital Network (ISDN) is a digital telephone/telecommunication network that carries voice, data, and video over an existing telephone network infrastructure. It requires an ISDN modem at both the ends of a transmission. ISDN is designed to provide a single interface for hooking up a telephone, fax machine, computer, etc. ISDN has two levels of service, i.e., Basic Rate Interface (BRI) and Primary Rate Interface (PRI).
    Answer option A is incorrect. The Point-to-Point Protocol, or PPP, is a data link protocol commonly used to establish a direct connection between two networking nodes. It can provide connection authentication, transmission encryption privacy, and compression. PPP is commonly used as a data link layer protocol for connection over synchronous and asynchronous circuits, where it has largely superseded the older, non-standard Serial Line Internet Protocol (SLIP) and telephone company mandated standards (such as Link Access Protocol, Balanced (LAPB) in the X.25 protocol suite). PPP was designed to work with numerous network layer protocols, including Internet Protocol (IP), Novell’s Internetwork Packet Exchange (IPX), NBF, and AppleTalk.
    Answer option D is incorrect. The X.25 protocol, adopted as a standard by the Consultative Committee for International Telegraph and Telephone (CCITT), is a commonly-used network protocol. The X.25 protocol allows computers on different public networks (such as CompuServe, Tymnet, or a TCP/IP network) to communicate through an intermediary computer at the network layer level. X.25’s protocols correspond closely to the data-link and physical-layer protocols defined in the Open Systems Interconnection (OSI) communication model.
  18. Which of the following policies is a set of rules designed to enhance computer security by encouraging users to employ strong passwords and use them properly?

    • Information protection policy
    • Remote access policy
    • Group policy
    • Password policy
    Explanation:
    A password policy is a set of rules designed to enhance computer security by encouraging users to employ strong passwords and use them properly. Password policies are account policies that are related to the users’ accounts. Such policies are password-related settings that provide different constraints for the password’s usage. Password policies can be configured to enforce users to provide passwords only in a specific way when they try to log on to their computers. These policies increase the effectiveness of the user’s computers. Answer option C is incorrect. A group policy specifies how programs, network resources, and the operating system work for users and computers in an organization.
    Answer option A is incorrect. An information protection policy ensures that information is appropriately protected from modification or disclosure.
    Answer option B is incorrect. Remote access policy is a document that outlines and defines acceptable methods of remotely connecting to the internal network.
  19. Which of the following biometric devices is used to take impressions of the friction ridges of the skin on the underside of the tip of the fingers?

    • Facial recognition device
    • Iris camera
    • Voice recognition voiceprint
    • Fingerprint reader
    Explanation:
    A fingerprint reader is used to take impressions of the friction ridges of the skin on the underside of the tip of the fingers. Fingerprints help in identifying users and are unique and different to everyone and do not change over time. Even identical twins who share their DNA do not have the same fingerprints. Police and Government agencies have used these modes in order to identify humans for many years, but other agencies are starting to use biometric fingerprint readers for identification in many different applications. A fingerprint is created when the friction ridges of the skin come in contact with a surface that is receptive to a print by means of an agent to form the print like perspiration, oil, ink, grease, and many more. The agent is then transferred to the surface and leaves an impression which creates the fingerprint.
    Answer option B is incorrect. An iris camera is used to perform recognition detection of a user’s identity by mathematical analysis of the random patterns that are visible within the iris of an eye from some distance. It is used to combine computer vision, pattern recognition, statistical inference, and optics.
    Answer option A is incorrect. A facial recognition device helps in viewing an image or video of a person and compares it to one that is in the database. It performs facial recognition by comparing the following: Structure, shape, and proportions of the face Distance between the eyes, nose, mouth, and jaw Upper outlines of the eye sockets The sides of the mouth Location of the nose and eyes The area surrounding the check bones. Answer option C is incorrect. A voice recognition voiceprint is a spectrogram, which is a graph that shows a sound’s frequency on the vertical axis and time on the horizontal axis. Different speech sounds help in creating different shapes on the graph. Spectrograms also use color or shades of gray to represent the acoustical qualities of sound.
  20. Peter, a malicious hacker, obtains e-mail addresses by harvesting them from postings, blogs, DNS listings, and Web pages. He then sends a large number of unsolicited commercial e-mail (UCE) messages to these addresses. Which of the following e-mail crimes is Peter committing?

    • E-mail spam
    • E-mail storm
    • E-mail bombing
    • E-mail spoofing
    Explanation:
    Peter is performing spamming activity. Spam is a term that refers to the unsolicited e-mails sent to a large number of e-mail users. The number of such e-mails is increasing day by day, as most companies now prefer to use e-mails for promoting their products. Because of these unsolicited e-mails, legitimate e-mails take a much longer time to deliver to their destination. The attachments sent through spam may also contain viruses. However, spam can be stopped by implementing spam filters on servers and e-mail clients.
    Answer option C is incorrect. Mail bombing is an attack that is used to overwhelm mail servers and clients by sending a large number of unwanted e-mails. The aim of this type of attack is to completely fill the recipient’s hard disk with immense, useless files, causing at best irritation, and at worst total computer failure. E-mail filtering and properly configuring email relay functionality on mail servers can be helpful for protection against this type of attack.
    Answer option B is incorrect. An e-mail storm is a sudden spike of Reply All messages on an e-mail distribution list, usually caused by a controversial or misdirected message. Such storms start when multiple members of the distribution list reply to the entire list at the same time
    in response to an instigating message. Other members soon respond, usually adding vitriol to the discussion, asking to be removed from the list, or pleading for the cessation of messages. If enough members reply to these unwanted messages, this triggers a chain reaction of e-mail messages. The sheer load of traffic generated by these storms can render the e-mail servers carrying them inoperative, similar to a DDoS attack. Some e-mail viruses also have the capacity to create e-mail storms, by sending copies of themselves to an infected user’s contacts, including distribution lists, infecting the contacts in turn.
    Answer option D is incorrect. E-mail spoofing is a term used to describe e-mail activity in which the sender address and other parts of the e-mail header are altered to appear as though the e-mail originated from a different source. E-mail spoofing is a technique commonly used for spam e-mail and phishing to hide the origin of an e-mail message. By changing certain properties of the e-mail, such as the From, Return-Path, and Reply-To fields (which can be found in the message header), ill-intentioned users can make the e-mail appear to be from someone other than the actual sender. The result is that, although the e-mail appears to come from the address indicated in the From field, it actually comes from another source.