ECCouncil Updated 312-50v13 Exam Questions and Answers by elis

A counter-based authentication system is based on the HOTP (HMAC-Based One-Time Password) algorithm. It uses a shared secret and a moving counter to generate a one-time password (OTP). Each time the counter is incremented, a new OTP is generated and encrypted using the secret key.

Reference – CEH v13 Official Study Guide:

Module 5: System Hacking

Quote:

“HOTP generates a one-time password using a counter value and a secret key. This is a form of two-factor authentication, and the passwords are encrypted.”

Incorrect Options Explained:

A & B. These describe biometric systems, not counter-based OTPs.

D. Virtual passwords from passphrases are not counter-based systems.

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ARIN (American Registry for Internet Numbers) is a Regional Internet Registry (RIR) that provides information about IP address allocations and autonomous systems in North America. It’s used for WHOIS lookups and footprinting in reconnaissance.

A DHCP starvation assault is a pernicious computerized assault that objectives DHCP workers. During a DHCP assault, an unfriendly entertainer floods a DHCP worker with false DISCOVER bundles until the DHCP worker debilitates its stock of IP addresses. When that occurs, the aggressor can deny genuine organization clients administration, or even stock an other DHCP association that prompts a Man-in-the-Middle (MITM) assault.

In a DHCP Starvation assault, a threatening entertainer sends a huge load of false DISCOVER parcels until the DHCP worker thinks they’ve used their accessible pool. Customers searching for IP tends to find that there are no IP addresses for them, and they’re refused assistance. Furthermore, they may search for an alternate DHCP worker, one which the unfriendly entertainer may give. What’s more, utilizing a threatening or sham IP address, that unfriendly entertainer would now be able to peruse all the traffic that customer sends and gets.

In an unfriendly climate, where we have a malevolent machine running some sort of an instrument like Yersinia, there could be a machine that sends DHCP DISCOVER bundles. This malevolent customer doesn’t send a modest bunch – it sends a great many vindictive DISCOVER bundles utilizing sham, made-up MAC addresses as the source MAC address for each solicitation.

In the event that the DHCP worker reacts to every one of these false DHCP DISCOVER parcels, the whole IP address pool could be exhausted, and that DHCP worker could trust it has no more IP delivers to bring to the table to legitimate DHCP demands.

When a DHCP worker has no more IP delivers to bring to the table, ordinarily the following thing to happen would be for the aggressor to get their own DHCP worker. This maverick DHCP worker at that point starts giving out IP addresses.

The advantage of that to the assailant is that if a false DHCP worker is distributing IP addresses, including default DNS and door data, customers who utilize those IP delivers and begin to utilize that default passage would now be able to be directed through the aggressor’s machine. That is all that an unfriendly entertainer requires to play out a man-in-the-center (MITM) assault.

A hybrid attack combines the benefits of both dictionary and brute-force attacks. It takes words from a dictionary and applies modifications such as:

Appending or prepending numbers or symbols

Changing case (e.g., admin → Admin1!)

Leetspeak substitutions (e.g., p@ssw0rd)

From CEH v13 Official Courseware:

Module 6: Malware Threats

Topic: Password Cracking Methods

CEH v13 Study Guide states:

“A hybrid attack is a combination of dictionary and brute-force techniques. It takes dictionary words and mutates them to cover common variations, making it more effective than pure dictionary attacks.”

Incorrect Options:

A/B/D: These are not standard terminology in cryptographic or password auditing literature.