312-50v12 Exam Dumps - Certified Ethical Hacker Exam (CEHv12)

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.comWho 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):1. The client encodes data during a DNS request. The way it does this is often by prepending a bit of knowledge within the domain of the request. for instance : mypieceofdata.server1.example.com2. The DNS request goes bent a DNS server.3. The DNS server finds out the A register of your domain with the IP address of your server.4. The request for mypieceofdata.server1.example.com is forwarded to the server.5. The server processes regardless of the mypieceofdata was alleged to do. Let’s assume it had been an HTTP request.6. The server replies back over DNS and woop woop, we’ve got signal.

Bypassing Firewalls through the DNS Tunneling Method DNS operates using UDP, and it has a 255-byte limit on outbound queries. Moreover, it allows only alphanumeric characters and hyphens. Such small size constraints on external queries allow DNS to be used as an ideal choice to perform data exfiltration by various malicious entities. Since corrupt or malicious data can be secretly embedded into the DNS protocol packets, even DNSSEC cannot detect the abnormality in DNS tunneling. It is effectively used by malware to bypass the firewall to maintain communication between the victim machine and the C&C server. Tools such as NSTX (https://sourceforge.net), Heyoka (http://heyoka.sourceforge.netuse), and Iodine (https://code.kryo.se) use this technique of tunneling traffic across DNS port 53. CEH v11 Module 12 Page 994

Internet of Medical Things (IoMT) devices are internet-connected medical devices that can collect, transfer, and analyze data over a network. They can provide improved patient care and comfort, but they also pose security challenges and risks, as they can be targeted by cyberattacks, such as ransomware, that can compromise their functionality, integrity, or confidentiality. Ransomware is a type of malware that encrypts the victim’s data or system and demands a ransom for its decryption or restoration. Ransomware attacks can cause serious harm to healthcare organizations, as they can disrupt their operations, endanger their patients, and damage their reputation.

To protect IoMT devices from ransomware attacks, the main recommendation is to use network segmentation to isolate IoMT devices from the main network. Network segmentation is a technique that divides a network into smaller subnetworks, each with its own security policies and controls. Network segmentation can prevent or limit the spread of ransomware from one subnetwork to another, as it restricts the communication and access between them. Network segmentation can also improve the performance, visibility, and manageability of the network, as it reduces the network congestion, complexity, and noise.

The other options are not as effective or feasible as network segmentation. Implementing multi-factor authentication for all IoMT devices may not be possible or practical, as some IoMT devices may not support or require user authentication, such as sensors or monitors. Disabling all wireless connectivity on IoMT devices may not be desirable or realistic, as some IoMT devices rely on wireless communication protocols, such as Wi-Fi, Bluetooth, or Zigbee, to function or transmit data. Regularly changing the IP addresses of all IoMT devices may not prevent or deter ransomware attacks, as ransomware can target devices based on other factors, such as their domain names, MAC addresses, or vulnerabilities. References:

• What Is Internet of Medical Things (IoMT) Security?
• 5 Steps to Secure Internet of Medical Things Devices
• Ransomware in Healthcare: How to Protect Your Organization
• [Network Segmentation: Definition, Benefits, and Best Practices]

The most probable subsequent action from the attacker based on the Cyber Kill Chain Methodology is to exploit the malicious payload delivered to the target organization and establish a foothold. This option works as follows:

• The Cyber Kill Chain Methodology is a framework that describes the stages of a cyberattack from the perspective of the attacker. It helps defenders to understand the attacker’s objectives, tactics, and techniques, and to design effective countermeasures. The Cyber Kill Chain Methodology consists of seven stages: reconnaissance, weaponization, delivery, exploitation, installation, command and control, and actions on objectives12.
• The delivery stage is the third stage in the Cyber Kill Chain Methodology, and it involves sending or transmitting the weaponized payload to the target system. The delivery stage can use various methods, such as email attachments, web links, removable media, or network protocols. The delivery stage aims to reach the target system and bypass any security controls, such as firewalls, antivirus, or email filters12.
• The exploitation stage is the fourth stage in the Cyber Kill Chain Methodology, and it involves executing the malicious payload on the target system. The exploitation stage can use various techniques, such as buffer overflows, code injection, or privilege escalation. The exploitation stage aims to exploit a vulnerability or a weakness in the target system and gain access to its resources, such as files, processes, or memory12.
• The installation stage is the fifth stage in the Cyber Kill Chain Methodology, and it involves installing a backdoor or a malware on the target system. The installation stage can use various tools, such as rootkits, trojans, or ransomware. The installation stage aims to establish a foothold on the target system and maintain persistence, which means to survive reboots, updates, or scans12.

Therefore, the most probable subsequent action from the attacker based on the Cyber Kill Chain Methodology is to exploit the malicious payload delivered to the target organization and establish a foothold, because:

• This action follows the logical sequence of the Cyber Kill Chain Methodology, as it is the next stage after the delivery stage.
• This action is consistent with the attacker’s goal, as it allows the attacker to gain access and control over the target system and prepare for further actions.
• This action is feasible, as the attacker has already delivered the malicious payload to the target system and may have bypassed some security controls.

The other options are not as probable as option B for the following reasons:

• A. The attacker will attempt to escalate privileges to gain complete control of the compromised system: This option is possible, but not the most probable, because it is not the next stage in the Cyber Kill Chain Methodology, but rather a technique that can be used in the exploitation stage or the installation stage. Privilege escalation is a method of increasing the level of access or permissions on a system, such as from a normal user to an administrator. Privilege escalation can help the attacker to gain complete control of the compromised system, but it is not a mandatory step, as the attacker may already have sufficient privileges or may use other techniques to achieve the same goal12.
• C. The attacker will initiate an active connection to the target system to gather more data: This option is possible, but not the most probable, because it is not the next stage in the Cyber Kill Chain Methodology, but rather a technique that can be used in the command and control stage or the actions on objectives stage. An active connection is a communication channel that allows the attacker to send commands or receive data from the target system, such as a remote shell or a botnet. An active connection can help the attacker to gather more data from the target system, but it is not a necessary step, as the attacker may already have enough data or may use other techniques to obtain more data12.
• D. The attacker will start reconnaissance to gather as much information as possible about the target: This option is not probable, because it is not the next stage in the Cyber Kill Chain Methodology, but rather the first stage. Reconnaissance is the process of collecting information about the target, such as its IP address, domain name, network structure, services, vulnerabilities, or employees. Reconnaissance is usually done before the delivery stage, as it helps the attacker to identify the target and plan the attack. Reconnaissance can be done again after the delivery stage, but it is not the most likely action, as the attacker may already have enough information or may focus on other actions12.

References:

• 1: The Cyber Kill Chain: The Seven Steps of a Cyberattack - EC-Council
• 2: Cyber Kill Chain® | Lockheed Martin