Free EC-Council 312-50v13 Practice Exams - Page 26 of 29

Question #251

In the field of cryptanalysis, what is meant by a “rubber-hose” attack?

A . Forcing the targeted keystream through a hardware-accelerated device such as an ASIC.
B . A backdoor placed into a cryptographic algorithm by its creator.
C . Extraction of cryptographic secrets through coercion or torture.
D . Attempting to decrypt ciphertext by making logical assumptions about the contents of the original plaintext.

Question #252

An audacious attacker is targeting a web server you oversee. He intends to perform a Slow HTTP POST attack, by manipulating ‘a’ HTTP connection. Each connection sends a byte of data every ‘b’ second, effectively holding up the connections for an extended period. Your server is designed to manage ‘m’ connections per second, but any connections exceeding this number tend to overwhelm the system. Given ‘a=100′ and variable ‘m’, along with the attacker’s intention of maximizing the attack duration ‘D=a*b’, consider the following scenarios.

Which is most likely to result in the longest duration of server unavailability?

A . m=110, b=20: Despite the attacker sending 100 connections, the server can handle 110 connections per second, therefore likely staying operative, regardless of the hold-up time per connection
B . m=90, b=15: The server can manage 90 connections per second, but the attacker’s 100 connections exceed this, and with each connection held up for 15 seconds, the attack duration could be significant
C . 95, b=10: Here, the server can handle 95 connections per second, but it falls short against the attacker’s 100 connections, albeit the hold-up time per connection is lower
D . m=105, b=12: The server can manage 105 connections per second, more than the attacker’s 100 connections, likely maintaining operation despite a moderate hold-up time

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Question #253

In the process of footprinting a target website, an ethical hacker utilized various tools to gather critical information. The hacker encountered a target site where standard web spiders were ineffective due to a specific file in its root directory. However, they managed to uncover all the files and web pages on the target site, monitoring the resulting incoming and outgoing traffic while browsing the website manually.

What technique did the hacker likely employ to achieve this?

A . Using Photon to retrieve archived URLs of the target website from archive.org
B . Using the Netcraft tool to gather website information
C . Examining HTML source code and cookies
D . User-directed spidering with tools like Burp Suite and WebScarab

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Question #254

You have been authorized to perform a penetration test against a website. You want to use Google dorks to footprint the site but only want results that show file extensions.

What Google dork operator would you use?

A . filetype
B . ext
C . inurl
D . site

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Question #255

Null sessions are un-authenticated connections (not using a username or password.) to an NT or 2000 system.

Which TCP and UDP ports must you filter to check null sessions on your network?

A . 137 and 139
B . 137 and 443
C . 139 and 443
D . 139 and 445

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Question #256

The collection of potentially actionable, overt, and publicly available information is known as

A . Open-source intelligence
B . Real intelligence
C . Social intelligence
D . Human intelligence

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Question #257

During the process of encryption and decryption, what keys are shared?

A . Private keys
B . User passwords
C . Public keys
D . Public and private keys

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Correct Answer: C
C

Explanation:

https://en.wikipedia.org/wiki/Public-key_cryptography

Public-key cryptography, or asymmetric cryptography, is a cryptographic system that uses pairs of keys: public keys (which may be known to others), and private keys (which may never be known by any except the owner). The generation of such key pairs depends on cryptographic algorithms which are based on mathematical problems termed one-way functions. Effective security requires keeping the private key private; the public key can be openly distributed without compromising security.

In such a system, any person can encrypt a message using the intended receiver’s public key, but that encrypted message can only be decrypted with the receiver’s private key. This allows, for instance, a server program to generate a cryptographic key intended for a suitable symmetric-key cryptography, then to use a client’s openly-shared public key to encrypt that newly generated symmetric key. The server can then send this encrypted symmetric key over an insecure channel to the client; only the client can decrypt it using the client’s private key (which pairs with the public key used by the server to encrypt the message). With the client and server both having the same symmetric key, they can safely use symmetric key encryption (likely much faster) to communicate over otherwise-insecure channels. This scheme has the advantage of not having to manually pre-share symmetric keys (a fundamentally difficult problem) while gaining the higher data throughput advantage of symmetric-key cryptography.

With public-key cryptography, robust authentication is also possible. A sender can combine a message with a private key to create a short digital signature on the message. Anyone with the sender’s corresponding public key can combine that message with a claimed digital signature; if the signature matches the message, the origin of the message is verified (i.e., it must have been made by the owner of the corresponding private key).

Public key algorithms are fundamental security primitives in modern cryptosystems, including applications and protocols which offer assurance of the confidentiality, authenticity and non-repudiability of electronic communications and data storage. They underpin numerous Internet standards, such as Transport Layer Security (TLS), S/MIME, PGP, and GPG. Some public key algorithms provide key distribution and secrecy (e.g., DiffieCHellman key exchange), some provide digital signatures (e.g., Digital Signature Algorithm), and some provide both (e.g., RSA). Compared to symmetric encryption, asymmetric encryption is rather slower than good symmetric encryption, too slow for many purposes. Today’s cryptosystems (such as TLS, Secure Shell) use both symmetric encryption and asymmetric encryption.

Question #258

Cross-site request forgery involves:

A . A request sent by a malicious user from a browser to a server
B . Modification of a request by a proxy between client and server
C . A browser making a request to a server without the user’s knowledge
D . A server making a request to another server without the user’s knowledge

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Correct Answer: C
C

Explanation:

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.

Question #259

Steve, a scientist who works in a governmental security agency, developed a technological solution to identify people based on walking patterns and implemented this approach to a physical control access.

A camera captures people walking and identifies the individuals using Steve’s approach.

After that, people must approximate their RFID badges. Both the identifications are required to open the door. In this case, we can say:

A . Although the approach has two phases, it actually implements just one authentication factor
B . The solution implements the two authentication factors: physical object and physical characteristic
C . The solution will have a high level of false positives
D . Biological motion cannot be used to identify people

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Question #260

You are the chief cybersecurity officer at CloudSecure Inc., and your team is responsible for securing a cloudbased application that handles sensitive customer data. To ensure that the data is protected from breaches, you have decided to implement encryption for both data-at-rest and data-in-transit. The development team suggests using SSL/TLS for securing data in transit. However, you want to also implement a mechanism to detect if the data was tampered with during transmission.

Which of the following should you propose?

A . Implement IPsec in addition to SSL/TLS.
B . Qswitch to using SSH for data transmission.
C . Use the cloud service provider’s built-in encryption services.
D . Encrypt data using the AES algorithm before transmission.

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