312-50v13 Exam Dumps - ECCouncil CEH v13 Questions and Answers

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 –send-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 (–send-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 –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 –spoof-mac option to spoof the MAC address as described in the MAC Address Spoofing section.

In CEH v13 Module 11: Hacking Wireless Networks, Wardriving is explained as the practice of driving around with a Wi-Fi-enabled device to detect open or vulnerable wireless networks.

Key Characteristics of Wardriving:

Involves using laptops, smartphones, or specialized devices with Wi-Fi antennas.

Tools like NetStumbler, Kismet, or WiGLE may be used.

Often includes GPS tagging of discovered networks.

Used to identify unsecured access points for later exploitation.

Option Clarification:

A. GPS mapping: May be used with wardriving, but not the act itself.

B. Spectrum analysis: Measures RF spectrum usage; not network discovery.

C. Wardriving: Correct – searching for Wi-Fi networks while driving.

D. Wireless sniffing: Captures traffic; can happen during wardriving, but broader in scope.

Using default settings on a web server is considered a security risk because it can reveal the server software type and version, which can help attackers identify potential vulnerabilities and launch targeted attacks. For example, if the default settings include a server signature that displays the name and version of the web server software, such as Apache 2.4.46, an attacker can search for known exploits or bugs that affect that specific software and version. Additionally, default settings may also include other insecure configurations, such as weak passwords, unnecessary services, or open ports, that can expose the web server to unauthorized access or compromise.

The best initial step to mitigate this risk is to change the default settings to hide or obscure the server software type and version, as well as to disable or remove any unnecessary or insecure features. For example, to hide the server signature, one can modify the ServerTokens and ServerSignature directives in the Apache configuration file1. Alternatively, one can use a web application firewall or a reverse proxy to mask the server information from the client requests2. Changing the default settings can reduce the attack surface and make it harder for attackers to exploit the web server.

Jamming and scrambling are attacks targeting the physical layer of the OSI model, often affecting wireless communication by generating interference to disrupt signal transmission. To mitigate such attacks, one advanced countermeasure is the use of Cognitive Radios.

According to CEH v13 Official Courseware:

Cognitive radios are intelligent radio systems capable of sensing the radio frequency (RF) environment and dynamically adjusting their operating parameters (e.g., frequency, modulation) to avoid interference and jamming.

They enable dynamic spectrum access and help in improving spectrum efficiency and resilience against jamming.

This approach falls under physical-layer security mechanisms.

Incorrect Options:

A. gets and strcpy are unsafe functions vulnerable to buffer overflow, not relevant to DoS protection.

B. Allowing all types of packets increases risk and is not a mitigation.

D. TCP SYN cookies protect against SYN flood attacks and disabling them weakens security.

Reference – CEH v13 Official Courseware:

Module 10: Denial-of-Service (DoS) Attacks

Section: “Defensive Strategies Against Jamming and DoS Attacks”

Subsection: “Physical Layer Countermeasures”

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In CEH v13 Module 05: System Hacking, and in lab-based exploitation exercises, this is a classic fuzzer for buffer overflow testing.

The script creates increasingly larger strings of "A" (50, 100, 150...).

These are passed as arguments to different vulnerable commands on the target service (127.0.0.1:9999).

The goal is to trigger a crash, typically when input exceeds buffer limits (i.e., buffer overflow).

This is part of exploit development to identify the offset and locate the instruction pointer overwrite (EIP overwrite).

Launching Fileless Malware through Phishing Attackers commonly use social engineering techniques such as phishing to spread fileless malware to the target systems. Fileless malware exploits vulnerabilities in system tools to load and run malicious payloads on the victim’s machine to compromise the sensitive information stored in the process memory. (P.978/962)

MX (Mail Exchange) records in DNS define the mail servers responsible for receiving email for a domain. Each MX record has a priority value.

Important concept:

A lower number indicates a higher priority.

Email servers attempt delivery to the mail server with the lowest priority first.

For example:

If MX records are:

10 mail1.example.com

20 mail2.example.com

Then mail1 will be tried first. If it fails, mail2 will be used.

So the statement “MX record priority increases as the number increases” is false.

https://owasp.org/www-community/attacks/csrf

Cross-Site Request Forgery (CSRF) is an attack that forces an end user to execute unwanted actions on a web application in which they’re currently authenticated. With a little help of social engineering (such as sending a link via email or chat), an attacker may trick the users of a web application into executing actions of the attacker’s choosing. If the victim is a normal user, a successful CSRF attack can force the user to perform state changing requests like transferring funds, changing their email address, and so forth. If the victim is an administrative account, CSRF can compromise the entire web application.

CSRF is an attack that tricks the victim into submitting a malicious request. It inherits the identity and privileges of the victim to perform an undesired function on the victim’s behalf. For most sites, browser requests automatically include any credentials associated with the site, such as the user’s session cookie, IP address, Windows domain credentials, and so forth. Therefore, if the user is currently authenticated to the site, the site will have no way to distinguish between the forged request sent by the victim and a legitimate request sent by the victim.

CSRF attacks target functionality that causes a state change on the server, such as changing the victim’s email address or password, or purchasing something. Forcing the victim to retrieve data doesn’t benefit an attacker because the attacker doesn’t receive the response, the victim does. As such, CSRF attacks target state-changing requests.

It’s sometimes possible to store the CSRF attack on the vulnerable site itself. Such vulnerabilities are called “stored CSRF flaws”. This can be accomplished by simply storing an IMG or IFRAME tag in a field that accepts HTML, or by a more complex cross-site scripting attack. If the attack can store a CSRF attack in the site, the severity of the attack is amplified. In particular, the likelihood is increased because the victim is more likely to view the page containing the attack than some random page on the Internet. The likelihood is also increased because the victim is sure to be authenticated to the site already.

Command Breakdown:

nc: Netcat utility

-l: Listen mode

-u: Use UDP protocol

-p 55555: Listen on port 55555

< /etc/passwd: Redirects the contents of /etc/passwd into the socket

This means that when a connection is made to UDP port 55555, the contents of /etc/passwd will be sent to the connecting host.

From CEH v13 Courseware:

Module 8: Sniffing & Network Communication Tools

CEH v13 Study Guide states:

“Netcat can be used to serve files, open shells, or transfer data. Using input redirection, it can stream file contents to anyone who connects.”

Incorrect Options:

A: Does not log; it outputs /etc/passwd

C: The opposite; it serves the file, doesn’t grab it

D: Netcat does not delete files with this syntax

LM hashes are split into two 16-character halves (each representing 7-character blocks). If the original password is less than 8 characters, the second half of the LM hash will always be a constant:

"AAD3B435B51404EE"

This known value is used to pad the second half of the password, and it signals that the original password was 7 characters or fewer.

In the options:

B. 44EFCE164AB921CQAAD3B435B51404EE ← ends with AAD3B435B51404EE → < 8 chars

E. B757BF5C0D87772FAAD3B435B51404EE ← also ends with AAD3B435B51404EE → < 8 chars

From CEH v13 Official Courseware:

Module 6: Malware Threats → LM Hash Weaknesses

OS fingerprinting helps attackers identify the operating system and version running on a target host. This allows them to:

Determine potential vulnerabilities

Choose appropriate exploits for the OS version and configuration

Bypass ineffective defenses

From CEH v13 Courseware:

Module 3: Scanning Networks

Topic: Active and Passive OS Fingerprinting

CEH v13 Study Guide states:

“Fingerprinting identifies the OS type/version and helps attackers choose specific exploits that apply to that system.”

Incorrect Options:

A: Software enumeration is different from OS fingerprinting.

B/C: Misleading or incorrect in this context.

A hybrid attack combines a dictionary and brute-force approach. Given that:

Passwords are required to be complex

Users still often choose predictable variations (e.g., Password123!, Welcome@2024)

A hybrid attack is best suited because it applies common mutations to known words—much faster than full brute force and more effective than a plain dictionary attack.

From CEH v13 Courseware:

Module 6: Password Cracking → Attack Techniques

CEH v13 Study Guide states:

“Hybrid attacks combine the speed of dictionary attacks with some of the thoroughness of brute-force. It’s ideal when users use complex but predictable passwords.”

Incorrect Options:

A: Online attacks are slow and may trigger account lockouts.

B: Plain dictionary attacks won’t cover variations like “P@ssw0rd!”

C: Brute-force would be too slow for complex passwords.

The best security practice in this scenario is to implement IEEE 802.1X. This is a port-based Network Access Control (NAC) protocol that provides authentication for devices before they are allowed to transmit traffic on the network. It ensures that only authorized users/devices can access the network through physical (wired) or wireless connections.

CEH v13 Official Courseware states:

“802.1X provides a framework for authenticating and authorizing devices attached to a LAN port, enforcing port-based network access control. It helps prevent unauthorized users from connecting to an internal network, particularly in environments where physical access to network jacks cannot be fully controlled.”

Incorrect Options:

A. Disabling unused ports is a good practice, but students may still use open ports intended for authorized personnel. It does not scale or provide identity-based access control.

B. Separating users in VLANs helps in segmentation, but it does not prevent unauthorized physical access to ports.

D. Asking students to use wireless is administrative, not a technical enforcement measure.

Reference – CEH v13 Guide:

Module 04: Enumeration

Topic: Network Access Control (802.1X) and Switch Port Security

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DROWN is a serious vulnerability that affects HTTPS and other services that deem SSL and TLS, some of the essential cryptographic protocols for net security. These protocols allow everyone on the net to browse the net, use email, look on-line, and send instant messages while not third-parties being able to browse the communication.

DROWN allows attackers to break the encryption and read or steal sensitive communications, as well as passwords, credit card numbers, trade secrets, or financial data. At the time of public disclosure on March 2016, our measurements indicated thirty third of all HTTPS servers were vulnerable to the attack. fortuitously, the vulnerability is much less prevalent currently. As of 2019, SSL Labs estimates that one.2% of HTTPS servers are vulnerable.

What will the attackers gain?

Any communication between users and the server. This typically includes, however isn’t limited to, usernames and passwords, credit card numbers, emails, instant messages, and sensitive documents. under some common scenarios, an attacker can also impersonate a secure web site and intercept or change the content the user sees.

Who is vulnerable?

Websites, mail servers, and other TLS-dependent services are in danger for the DROWN attack. At the time of public disclosure, many popular sites were affected. we used Internet-wide scanning to live how many sites are vulnerable:

Operators of vulnerable servers got to take action. there’s nothing practical that browsers or end-users will do on their own to protect against this attack.

Is my site vulnerable?

Modern servers and shoppers use the TLS encryption protocol. However, because of misconfigurations, several servers also still support SSLv2, a 1990s-era precursor to TLS. This support did not matter in practice, since no up-to-date clients really use SSLv2. Therefore, despite the fact that SSLv2 is thought to be badly insecure, until now, simply supporting SSLv2 wasn’t thought of a security problem, is a clients never used it.

DROWN shows that merely supporting SSLv2 may be a threat to fashionable servers and clients. It modern associate degree attacker to modern fashionable TLS connections between up-to-date clients and servers by sending probes to a server that supports SSLv2 and uses the same private key.

A server is vulnerable to DROWN if:

It allows SSLv2 connections. This is surprisingly common, due to misconfiguration and inappropriate default settings.

Its private key is used on any other serverthat allows SSLv2 connections, even for another protocol. Many companies reuse the same certificate and key on their web and email servers, for instance. In this case, if the email server supports SSLv2 and the web server does not, an attacker can take advantage of the email server to break TLS connections to the web server.

How do I protect my server?

To protect against DROWN, server operators need to ensure that their private keys software used anyplace with server computer code that enables SSLv2 connections. This includes net servers, SMTP servers, IMAP and POP servers, and the other software that supports SSL/TLS.

Disabling SSLv2 is difficult and depends on the particular server software. we offer instructions here for many common products:

OpenSSL: OpenSSL may be a science library employed in several server merchandise. For users of OpenSSL, the simplest and recommended solution is to upgrade to a recent OpenSSL version. OpenSSL 1.0.2 users ought to upgrade to 1.0.2g. OpenSSL 1.0.1 users ought to upgrade to one.0.1s. Users of older OpenSSL versions ought to upgrade to either one in every of these versions. (Updated March thirteenth, 16:00 UTC) Microsoft IIS (Windows Server): Support for SSLv2 on the server aspect is enabled by default only on the OS versions that correspond to IIS 7.0 and IIS seven.5, particularly Windows scene, Windows Server 2008, Windows seven and Windows Server 2008R2. This support is disabled within the appropriate SSLv2 subkey for ‘Server’, as outlined in KB245030. albeit users haven’t taken the steps to disable SSLv2, the export-grade and 56-bit ciphers that build DROWN possible don’t seem to be supported by default.

Network Security Services (NSS): NSS may be a common science library designed into several server merchandise. NSS versions three.13 (released back in 2012) and higher than ought to have SSLv2 disabled by default. (A little variety of users might have enabled SSLv2 manually and can got to take steps to disable it.) Users of older versions ought to upgrade to a more moderen version. we tend to still advocate checking whether or not your non-public secret is exposed elsewhere

Other affected software and in operation systems:

Instructions and data for: Apache, Postfix, Nginx, Debian, Red Hat

Browsers and other consumers: practical nothing practical that net browsers or different client computer code will do to stop DROWN. only server operators ar ready to take action to guard against the attack.

A rootkit is a type of stealth malware designed to hide the existence of certain processes or programs from normal detection methods. It can:

Hide itself and other processes

Conceal files and registry entries

Intercept system calls or keystrokes (keylogging)

Maintain persistent access

From CEH v13 Courseware:

Module 6: Malware Threats → Rootkits

Incorrect Options:

A: A Trojan may offer remote access but doesn't necessarily hide itself.

C: DoS tools are used to overload systems, not hide.

D: Scanners detect vulnerabilities, not conceal activities.

E: A backdoor may provide unauthorized access, but rootkits focus on hiding.