Free EC-Council 312-50v13 Practice Exams - Page 22 of 29

Question #211

Switches maintain a CAM Table that maps individual MAC addresses on the network to physical ports on the switch.

In MAC flooding attack, a switch is fed with many Ethernet frames, each containing different source MAC addresses, by the attacker. Switches have a limited memory for mapping various MAC addresses to physical ports.

What happens when the CAM table becomes full?

A . Switch then acts as hub by broadcasting packets to all machines on the network
B . The CAM overflow table will cause the switch to crash causing Denial of Service
C . The switch replaces outgoing frame switch factory default MAC address of FF:FF:FF:FF:FF:FF
D . Every packet is dropped and the switch sends out SNMP alerts to the IDS port

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Question #212

John, a professional hacker, decided to use DNS to perform data exfiltration on a target network, in this process, he embedded malicious data into the DNS protocol packets that even DNSSEC cannot detect. Using this technique. John successfully injected malware to bypass a firewall and maintained communication with the victim machine and C&C server.

What is the technique employed by John to bypass the firewall?

A . DNS cache snooping
B . DNSSEC zone walking
C . DNS tunneling method
D . DNS enumeration

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Correct Answer: C
C

Explanation:

DNS tunneling may be a method wont to send data over the DNS protocol, a protocol which has never been intended for data transfer. due to that, people tend to overlook it and it’s become a well-liked but effective tool in many attacks.

Most popular use case for DNS tunneling is obtaining free internet through bypassing captive portals at airports, hotels, or if you are feeling patient the not-so-cheap on the wing Wi-Fi.

On those shared internet hotspots HTTP traffic is blocked until a username/password is provided, however DNS traffic is usually still allowed within the background: we will encode our HTTP traffic over DNS and voilà, we’ve internet access.

This sounds fun but reality is, browsing anything on DNS tunneling is slow. Like, back to 1998 slow. Another more dangerous use of DNS tunneling would be bypassing network security devices (Firewalls, DLP appliances…) to line up an immediate and unmonitored communications channel on an organisation’s network. Possibilities here are endless: Data exfiltration, fixing another penetration testing tool… you name it.

To make it even more worrying, there’s an outsized amount of easy to use DNS tunneling tools out there.

There’s even a minimum of one VPN over DNS protocol provider (warning: the planning of the web site is hideous, making me doubt on the legitimacy of it).

As a pentester all this is often great, as a network admin not such a lot.

How does it work:

For those that ignoramus about DNS protocol but still made it here, i feel you deserve a really brief explanation on what DNS does: DNS is sort of a phonebook for the web, it translates URLs (human-friendly language, the person’s name), into an IP address (machine-friendly language, the phone number). That helps us remember many websites, same as we will remember many people’s names.

For those that know what DNS is i might suggest looking here for a fast refresh on DNS protocol, but briefly what you would like to understand is:

• A Record: Maps a website name to an IP address. example.com ? 12.34.52.67

• NS Record (a.k.a. Nameserver record): Maps a website name to an inventory of DNS servers, just in case our website is hosted in multiple servers.

example.com ? server1.example.com, server2.example.com Who is involved in DNS tunneling?

• Client. Will launch DNS requests with data in them to a website.

• One Domain that we will configure. So DNS servers will redirect its requests to an outlined server of our own.

• Server. this is often the defined nameserver which can ultimately receive the DNS requests.

The 6 Steps in DNS tunneling (simplified):

Question #213

John, a professional hacker, targeted an organization that uses LDAP for accessing distributed directory services. He used an automated tool to anonymously query the IDAP service for sensitive information such as usernames. addresses, departmental details, and server names to launch further attacks on the target organization.

What is the tool employed by John to gather information from the IDAP service?

A . jxplorer
B . Zabasearch
C . EarthExplorer
D . Ike-scan

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Question #214

The change of a hard drive failure is once every three years. The cost to buy a new hard drive is $300. It will require 10 hours to restore the OS and software to the new hard disk. It will require a further 4 hours to restore the database from the last backup to the new hard disk. The recovery person earns $10/hour. Calculate the SLE, ARO, and ALE. Assume the EF = 1(100%).

What is the closest approximate cost of this replacement and recovery operation per year?

A . $1320
B . $440
C . $100
D . $146

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Question #214

The change of a hard drive failure is once every three years. The cost to buy a new hard drive is $300. It will require 10 hours to restore the OS and software to the new hard disk. It will require a further 4 hours to restore the database from the last backup to the new hard disk. The recovery person earns $10/hour. Calculate the SLE, ARO, and ALE. Assume the EF = 1(100%).

What is the closest approximate cost of this replacement and recovery operation per year?

A . $1320
B . $440
C . $100
D . $146

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Question #214

The change of a hard drive failure is once every three years. The cost to buy a new hard drive is $300. It will require 10 hours to restore the OS and software to the new hard disk. It will require a further 4 hours to restore the database from the last backup to the new hard disk. The recovery person earns $10/hour. Calculate the SLE, ARO, and ALE. Assume the EF = 1(100%).

What is the closest approximate cost of this replacement and recovery operation per year?

A . $1320
B . $440
C . $100
D . $146

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Question #217

Andrew is an Ethical Hacker who was assigned the task of discovering all the active devices hidden by a restrictive firewall in the IPv4 range in a given target network.

Which of the following host discovery techniques must he use to perform the given task?

A . UDP scan
B . TCP Maimon scan
C . arp ping scan
D . ACK flag probe scan

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Correct Answer: C
C

Explanation:

One of the most common Nmap usage scenarios is scanning an Ethernet LAN. Most LANs, especially those that use the private address range granted by RFC 1918, do not always use the overwhelming majority of IP addresses. When Nmap attempts to send a raw IP packet, such as an ICMP echo request, the OS must determine a destination hardware (ARP) address, such as the target IP, so that the Ethernet frame can be properly addressed. .. This is required to issue a series of ARP requests. This is best illustrated by an example where a ping scan is attempted against an Area Ethernet host. The Csend-ip option tells Nmap to send IP-level packets (rather than raw Ethernet), even on area networks. The Wireshark output of the three ARP requests and their timing have been pasted into the session.

Raw IP ping scan example for offline targets

This example took quite a couple of seconds to finish because the (Linux) OS sent three ARP requests at 1 second intervals before abandoning the host. Waiting for a few seconds is excessive, as long as the ARP response usually arrives within a few milliseconds. Reducing this timeout period is not a priority for OS vendors, as the overwhelming majority of packets are sent to the host that actually exists. Nmap, on the other hand, needs to send packets to 16 million IP s given a target like 10.0.0.0/8. Many targets are pinged in parallel, but waiting 2 seconds each is very delayed.

There is another problem with raw IP ping scans on the LAN. If the destination host turns out to be unresponsive, as in the previous example, the source host usually adds an incomplete entry for that destination IP to the kernel ARP table. ARP tablespaces are finite and some operating systems become unresponsive when full. If Nmap is used in rawIP mode (Csend-ip), Nmap may have to wait a few minutes for the ARP cache entry to expire before continuing host discovery.

ARP scans solve both problems by giving Nmap the highest priority. Nmap issues raw ARP requests and handles retransmissions and timeout periods in its sole discretion. The system ARP cache is bypassed. The example shows the difference. This ARP scan takes just over a tenth of the time it takes for an equivalent IP.

Example b ARP ping scan of offline target

In example b, neither the -PR option nor the -send-eth option has any effect. This is often because ARP has a default scan type on the Area Ethernet network when scanning Ethernet hosts that Nmap discovers. This includes traditional wired Ethernet as 802.11 wireless networks. As mentioned above, ARP scanning is not only more efficient, but also more accurate. Hosts frequently block IP-based ping packets, but usually cannot block ARP requests or responses and communicate over the network. Nmap uses ARP instead of all targets on equivalent targets, even if different ping types (such as -PE and -PS) are specified. LAN.. If you do not need to attempt an ARP scan at all, specify C send-ip as shown in Example a “Raw IP Ping Scan for Offline Targets”.

If you give Nmap control to send raw Ethernet frames, Nmap can also adjust the source MAC address. If you have the only PowerBook in your security conference room and a large ARP scan is initiated from an Apple-registered MAC address, your head may turn to you. Use the Cspoof-mac option to spoof the MAC address as described in the MAC Address Spoofing section.

Question #218

What ports should be blocked on the firewall to prevent NetBIOS traffic from not coming through the firewall if your network is comprised of Windows NT, 2000, and XP?

A . 110
B . 135
C . 139
D . 161
E . 445
F . 1024

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Question #219

John, a professional hacker, performs a network attack on a renowned organization and gains unauthorized access to the target network. He remains in the network without being detected for a long time and obtains sensitive information without sabotaging the organization.

Which of the following attack techniques is used by John?

A . Advanced persistent theft
B . threat Diversion theft
C . Spear-phishing sites
D . insider threat

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Question #220

As a budding cybersecurity enthusiast, you have set up a small lab at home to learn more about wireless network security. While experimenting with your home Wi-Fi network, you decide to use a well-known hacking tool to capture network traffic and attempt to crack the Wi-Fi password. However, despite many attempts, you have been unsuccessful. Your home Wi-Fi network uses WPA2 Personal with AES encryption.

Why are you finding it difficult to crack the Wi-Fi password?

A . The Wi-Fi password is too complex and long
B . Your hacking tool is outdated
C . The network is using an uncrackable encryption method
D . The network is using MAC address filtering.

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