Exactprep 312-50v13 Questions

The protocol that you would recommend to the team to achieve the secure exchange of the symmetric key is the Diffie-Hellman protocol. The Diffie-Hellman protocol is a key agreement protocol that allows two or more parties to establish a shared secret key over an unsecured communication channel, without having to exchange the key itself. The Diffie-Hellman protocol works as follows12:

The parties agree on a large prime number p and a generator g, which are public parameters that can be known by anyone.

Each party chooses a random private number a or b, which are kept secret from anyone else.

Each party computes a public value A or B, by raising g to the power of a or b modulo p, i.e., A = g^a mod p and B = g^b mod p.

Each party sends their public value A or B to the other party over the unsecured channel.

Each party computes the shared secret key K, by raising the received public value to the power of their own private number modulo p, i.e., K = A^b mod p = B^a mod p.

The parties can now use the shared secret key K to encrypt and decrypt the data using a symmetric key encryption algorithm, such as AES or 3DES.

The Diffie-Hellman protocol can ensure the secure exchange of the symmetric key because it relies on the mathematical difficulty of computing discrete logarithms, which means that it is hard to find the private numbers a or b given the public values A or B, g, and p. Therefore, an attacker who intercepts the public values A or B cannot easily compute the shared secret key K, and thus cannot decrypt the data encrypted with K12.

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

A. Implementing SSL certificates on your company’s web servers: This option is not relevant because SSL certificates are not used to exchange symmetric keys, but to authenticate the identity of the web servers and to establish a secure connection using public key encryption. SSL certificates are digital certificates that contain the public key and the identity information of the web server, and are issued and signed by a trusted certificate authority (CA). When a client connects to a web server, the web server sends its SSL certificate to the client, who verifies it with the CA. If the verification is successful, the client and the web server use the public key in the certificate to exchange a symmetric key, which is then used to encrypt and decrypt the data. However, this option does not address the scenario of transmitting data over an unsecured communication channel, which may not involve web servers or SSL certificates34.

C. Switching all data transmission to the HTTPS protocol: This option is not sufficient because HTTPS protocol is not a protocol for exchanging symmetric keys, but a protocol for securing web traffic using SSL or TLS encryption. HTTPS protocol is a combination of HTTP protocol and SSL or TLS protocol, which means that it uses HTTP for the application layer communication and SSL or TLS for the transport layer encryption. When a client requests a web page from a web server using HTTPS protocol, the client and the web server establish a secure connection using SSL or TLS protocol, which involves the exchange of SSL certificates and a symmetric key, as explained in option A. Then, the client and the web server use the symmetric key to encrypt and decrypt the HTTP data. However, this option does not address the scenario of transmitting data over an unsecured communication channel, which may not involve web servers or HTTPS protocol5 .

D. Utilizing SSH for secure remote logins to the servers: This option is not applicable because SSH is not a protocol for exchanging symmetric keys, but a protocol for securing remote access to servers using public key authentication and encryption. SSH is a protocol that allows a client to securely connect to a server and execute commands or transfer files over an encrypted channel. SSH uses public key cryptography to authenticate the identity of the server and the client, and to exchange a symmetric key, which is then used to encrypt and decrypt the data. However, this option does not address the scenario of transmitting data over an unsecured communication channel, which may not involve remote logins or SSH protocol .

Hashing algorithms (such as SHA-256 or MD5) are used to generate a unique digital fingerprint of a file or message. Once the CFO approves the financial statement, generating a hash value for the document ensures that if any modification occurs (even a single bit), the hash value will change, indicating a breach in data integrity.

This solution directly addresses integrity — one of the three components of the CIA triad (Confidentiality, Integrity, Availability). Password protection or transferring via USB does not ensure integrity; they offer access control and delivery security.

In the Windows security model, SID ending in -500 is reserved for the built-in Administrator account. The SID seen in the image:

S-1-5-21-343818398-789336058-1343024091-500 → maps to user Joe

This proves that Joe is the true built-in administrator account on the domain EARTH.

From CEH v13 Courseware:

Module 4: Enumeration

Topic: SID Enumeration and Account Discovery

CEH v13 Study Guide states:

“In Windows, the account with RID 500 is always the default Administrator account. Even if renamed, its SID remains ending in -500. Enumeration of this SID allows attackers to identify privileged accounts.”

Incorrect Options:

A: Incomplete — it is not just that Joe has SID 500, but that SID 500 means Joe is the administrator.

B/C: These commands don’t validate Guest account status.

E: Incorrect — these commands explicitly prove administrator identity.

The command usage that would best serve your objective to find where the NTP server obtains the time from and to trace the list of NTP servers connected to the network is ntptrace -n -m 5 192.168.1.1. This command usage works as follows:

ntptrace is a tool that determines where a given NTP server gets its time from, and follows the chain of NTP servers back to their master time source. For example, a stratum 0 server, which is a device that directly obtains the time from a physical source, such as an atomic clock or a GPS receiver1.

-n is a flag that outputs host IP addresses instead of host names. This can be useful if the host names are not resolvable or if the IP addresses are more informative1.

-m 5 is a flag that specifies the maximum number of hosts to be traced. This can be useful to limit the output and avoid tracing irrelevant or unreachable hosts1.

192.168.1.1 is the IP address of the NTP server in the demilitarized zone, which is the starting point of the trace. This can be useful to find out the source and the path of the time synchronization for the network system1.

By using this command usage, the output will show the IP addresses, the stratum, the offset, the sync distance, and the reference ID of each NTP server in the chain, up to five hosts. This can provide valuable information about the accuracy, the reliability, and the security of the time service for the network system1.

The other options are not as suitable as option D for the following reasons:

A. ntptrace -m 5 192.168.1.1: This option is similar to option D, but it does not use the -n flag, which means that it will output host names instead of IP addresses. This can be less useful if the host names are not resolvable or if the IP addresses are more informative1.

B. tptrace 192.1681.: This option is incorrect because it uses a wrong tool name and a wrong IP address. tptrace is not a valid tool name, and 192.1681. is not a valid IP address. The correct tool name is ntptrace, and the correct IP address is 192.168.1.11.

C. ntptrace -n localhost: This option is not effective because it uses localhost as the starting point of the trace, which means that it will only show the local host’s time source. This can be useful to check the local host’s time configuration, but it does not help to find out the time source and the trace of the NTP server in the demilitarized zone, which is the objective of this scenario1.