Risk assessment is a key process in security management that identifies, evaluates, and prioritizes risks to organizational operations and assets. It considers various controls and safeguards to mitigate those risks.
Administrative safeguards are part of the components used in risk assessments and include:
* Policies
* Procedures
* Training
* Security awareness programs
* Incident response planning
From CEH v13:
* Module 1: Introduction to Ethical Hacking
* Module 20: Cryptography (as it discusses risk management and governance)
* Topic: Security Controls and Risk Management Frameworks
CEH v13 Official Courseware states:
"Administrative controls, also known as administrative safeguards, form a critical component of risk assessments. These include documented security policies, user training, security audits, and incident response plans that help an organization manage and reduce risks." Incorrect Options:
* B. Physical security is a type of safeguard but not typically referred to as a "component" of a risk assessment itself.
* C. DMZ (Demilitarized Zone) is a network architecture concept, not a risk assessment component.
* D. Logical interface refers to system architecture and network segmentation-not risk assessment methodology.
Reference:CEH v13 Study Guide - Module 1: Introduction to Ethical Hacking # Section: "Risk Management Concepts"NIST SP 800-30: Guide for Conducting Risk Assessments

Comprehensive and Detailed Explanation:
Non-repudiation ensures that a sender cannot deny having sent a message. This is typically achieved through digital signatures or logs which verify the origin and integrity of communications.
From CEH v13 Courseware:
* Module 10: Cryptography # Security Services
* "Non-repudiation prevents entities from denying their actions, such as sending emails or digital transactions." Reference: NIST SP 800-53 - Non-repudiation defined under Access Control and Audit

To block NetBIOS and related Windows networking traffic from traversing a firewall (especially from external sources), you should block the following ports:
* Port 135 (TCP/UDP): Microsoft RPC endpoint mapper (DCOM/RPC)
* Port 139 (TCP): NetBIOS Session Service
* Port 445 (TCP): Direct-hosted SMB over TCP/IP (Windows 2000+)
These ports are commonly used for:
* File sharing
* RPC-based communication
* Windows network services
From CEH v13 Official Courseware:
* Module 3: Scanning Networks
* Module 4: Enumeration
CEH v13 Study Guide states:
"To prevent external enumeration, remote file sharing, and NetBIOS attacks, administrators should block inbound access to ports 135, 139, and 445 on the firewall." Incorrect Options:
* A (110): POP3 mail service
* D (161): SNMP
* F (1024): High ephemeral port; not specific to NetBIOS
Reference:CEH v13 Study Guide - Module 4: Enumeration # NetBIOS Enumeration PreventionMicrosoft Security Best Practices - Block SMB Ports (135-139, 445)

In this attack KRACK is an acronym for Key Reinstallation Attack. KRACK may be a severe replay attack on Wi-Fi Protected Access protocol (WPA2), which secures your Wi-Fi connection. Hackers use KRACK to take advantage of a vulnerability in WPA2. When in close range of a possible victim, attackers can access and skim encrypted data using KRACK.
How KRACK Works
Your Wi-Fi client uses a four-way handshake when attempting to attach to a protected network. The handshake confirms that both the client - your smartphone, laptop, et cetera - and therefore the access point share the right credentials, usually a password for the network. This establishes the Pairwise passkey (PMK), which allows for encoding .
Overall, this handshake procedure allows for quick logins and connections and sets up a replacement encryption key with each connection. this is often what keeps data secure on Wi-Fi connections, and every one protected Wi-Fi connections use the four-way handshake for security. This protocol is that the reason users are encouraged to use private or credential-protected Wi-Fi instead of public connections.
KRACK affects the third step of the handshake, allowing the attacker to control and replay the WPA2 encryption key to trick it into installing a key already in use. When the key's reinstalled, other parameters related to it - the incremental transmit packet number called the nonce and therefore the replay counter - are set to their original values.
Rather than move to the fourth step within the four-way handshake, nonce resets still replay transmissions of the third step. This sets up the encryption protocol for attack, and counting on how the attackers replay the third-step transmissions, they will take down Wi-Fi security.
Why KRACK may be a Threat
Think of all the devices you employ that believe Wi-Fi. it isn't almost laptops and smartphones; numerous smart devices now structure the web of Things (IoT). due to the vulnerability in WPA2, everything connected to Wi-Fi is in danger of being hacked or hijacked.
Attackers using KRACK can gain access to usernames and passwords also as data stored on devices. Hackers can read emails and consider photos of transmitted data then use that information to blackmail users or sell it on the Dark Web.
Theft of stored data requires more steps, like an HTTP content injection to load malware into the system.
Hackers could conceivably take hold of any device used thereon Wi-Fi connection. Because the attacks require hackers to be on the brink of the target, these internet security threats could also cause physical security threats.
On the opposite hand, the necessity to be in close proximity is that the only excellent news associated with KRACK, as meaning a widespread attack would be extremely difficult.
Victims are specifically targeted. However, there are concerns that a experienced attacker could develop the talents to use HTTP content injection to load malware onto websites to make a more widespread affect.
Everyone is in danger from KRACK vulnerability. Patches are available for Windows and iOS devices, but a released patch for Android devices is currently in question (November 2017). There are issues with the discharge , and lots of question if all versions and devices are covered.
The real problem is with routers and IoT devices. These devices aren't updated as regularly as computer operating systems, and for several devices, security flaws got to be addressed on the manufacturing side. New devices should address KRACK, but the devices you have already got in your home probably aren't protected.
The best protection against KRACK is to make sure any device connected to Wi-Fi is patched and updated with the newest firmware. that has checking together with your router's manufacturer periodically to ascertain if patches are available.
The safest connection option may be a private VPN, especially when publicly spaces. If you would like a VPN for private use, avoid free options, as they need their own security problems and there'll even be issues with HTTPs. Use a paid service offered by a trusted vendor like Kaspersky. Also, more modern networks use WPA3 for better security.
Avoid using public Wi-Fi, albeit it's password protection. That password is out there to almost anyone, which reduces the safety level considerably.
All the widespread implications of KRACK and therefore the WPA2 vulnerability aren't yet clear. what's certain is that everybody who uses Wi-Fi is in danger and wishes to require precautions to guard their data and devices.

https://en.wikipedia.org/wiki/Subnetwork
This is a fairly simple question. You must to understand what a subnet mask is and how it works.
A subnetwork or subnet is a logical subdivision of an IP network.The practice of dividing a network into two or more networks is called subnetting.
Computers that belong to the same subnet are addressed with an identical most-significant bit-group in their IP addresses. This results in the logical division of an IP address into two fields: the network number or routing prefix and the rest field or host identifier. The rest field is an identifier for a specific host or network interface.
The routing prefix may be expressed in Classless Inter-Domain Routing (CIDR) notation written as the first address of a network, followed by a slash character (/), and ending with the bit-length of the prefix. For example, 198.51.100.0/24 is the prefix of the Internet Protocol version 4 network starting at the given address, having 24 bits allocated for the network prefix, and the remaining 8 bits reserved for host addressing.
Addresses in the range 198.51.100.0 to 198.51.100.255 belong to this network. The IPv6 address specification
2001:db8::/32 is a large address block with 296 addresses, having a 32-bit routing prefix.
For IPv4, a network may also be characterized by its subnet mask or netmask, which is the bitmask that when applied by a bitwise AND operation to any IP address in the network, yields the routing prefix. Subnet masks are also expressed in dot-decimal notation like an address. For example, 255.255.255.0 is the subnet mask for the prefix 198.51.100.0/24.