CompTIA Security+ Question L-16

A company’s employees were victims of a spear phishing campaign impersonating the CEO. The company would now like to implement a solution to improve the overall security posture by assuring their employees that email originated from the CEO. Which of the following controls could they implement to BEST meet this goal?

A. Spam filter
B. Digital signatures
C. Antivirus software
D. Digital certificates

Answer: B

Explanation:
A digital signature is a mathematical technique used to validate the authenticity and integrity of a message, software, or digital document. The digital equivalent of a handwritten signature or stamped seal, but offering far more inherent security, a digital signature is intended to solve the problem of tampering and impersonation in digital communications. Digital signatures can provide the added assurances of evidence to origin, identity and status of an electronic document, transaction or message, as well as acknowledging informed consent by the signer. Digital signatures are based on public key cryptography, also known as asymmetric cryptography. Using a public key algorithm such as RSA, one can generate two keys that are mathematically linked: one private and one public. To create a digital signature, signing software (such as an email program) creates a one-way hash of the electronic data to be signed. The private key is then used to encrypt the hash. The encrypted hash — along with other information, such as the hashing algorithm — is the digital signature. The reason for encrypting the hash instead of the entire message or document is that a hash function can convert an arbitrary input into a fixed length value, which is usually much shorter. This saves time since hashing is much faster than signing.

CompTIA Security+ Question K-63

Which of the following could cause a browser to display the message below?
“The security certificate presented by this website was issued for a different website’s address.”

A. The website certificate was issued by a different CA than what the browser recognizes in its trusted CAs.
B. The website is using a wildcard certificate issued for the company’s domain.
C. HTTPS://127.0.01 was used instead of HTTPS://localhost.
D. The website is using an expired self signed certificate.

Answer: C

Explanation:
PKI is a two-key, asymmetric system with four main components: certificate authority (CA), registration authority (RA), RSA (the encryption algorithm), and digital certificates. In typical public key infrastructure (PKI) arrangements, a digital signature from a certificate authority (CA) attests that a particular public key certificate is valid (i.e., contains correct information). Users, or their software on their behalf, check that the private key used to sign some certificate matches the public key in the CA’s certificate. Since CA certificates are often signed by other, “higher-ranking,” CAs, there must necessarily be a highest CA, which provides the ultimate in attestation authority in that particular PKI scheme. Localhost is a hostname that means this computer and may be used to access the computer’s own network services via its loopback network interface. Using the loopback interface bypasses local network interface hardware. In this case the HTTPS://127.0.01 was used and not HTTPS//localhost

CompTIA Security+ Question J-100

Which of the following BEST describes part of the PKI process?

A. User1 decrypts data with User2’s private key
B. User1 hashes data with User2’s public key
C. User1 hashes data with User2’s private key
D. User1 encrypts data with User2’s public key

Answer: D

Explanation:
In a PKI the sender encrypts the data using the receiver’s public key. The receiver decrypts the data using his own private key. PKI is a two-key, asymmetric system with four main components: certificate authority (CA), registration authority (RA), RSA (the encryption algorithm), and digital certificates. Messages are encrypted with a public key and decrypted with a private key. A PKI example: You want to send an encrypted message to Jordan, so you request his public key. Jordan responds by sending you that key. You use the public key he sends you to encrypt the message. You send the message to him.

Jordan uses his private key to decrypt the message.

CompTIA Security+ Question J-67

Which of the following is a step in deploying a WPA2-Enterprise wireless network?

A. Install a token on the authentication server
B. Install a DHCP server on the authentication server
C. Install an encryption key on the authentication server
D. Install a digital certificate on the authentication server

Answer: D

Explanation:
When setting up a wireless network, you’ll find two very different modes of Wi-Fi Protected Access (WPA) security, which apply to both the WPA and WPA2 versions. The easiest to setup is the Personal mode, technically called the Pre-Shared Key (PSK) mode. It doesn’t require anything beyond the wireless router or access points (APs) and uses a single passphrase or password for all users/devices. The other is the Enterprise mode —which should be used by businesses and organizations—and is also known as the RADIUS, 802.1X, 802.11i, or EAP mode. It provides better security and key management, and supports other enterprise-type functionality, such as VLANs and NAP. However, it requires an external authentication server, called a Remote Authentication Dial In User Service (RADIUS) server to handle the 802.1X authentication of users.

To help you better understand the process of setting up WPA/WPA2-Enterprise and 802.1X, here’s the basic overall steps: Choose, install, and configure a RADIUS server, or use a hosted service.

Create a certificate authority (CA), so you can issue and install a digital certificate onto the RADIUS server, which may be done as a part of the RADIUS server installation and configuration. Alternatively, you could purchase a digital certificate from a public CA, such as GoDaddy or Verisign, so you don’t have to install the server certificate on all the clients. If using EAP-TLS, you’d also create digital certificates for each end-user. On the server, populate the RADIUS client database with the IP address and shared secret for each AP. On the server, populate user data with usernames and passwords for each end-user. On each AP, configure the security for WPA/WPA2-Enterprise and input the RADIUS server IP address and the shared secret you created for that particular AP. On each Wi-Fi computer and device, configure the security for WPA/WPA2-Enterprise and set the 802.1X authentication settings.

CompTIA Security+ Question I-74

Signed digital certificates used to secure communication with a web server are MOST commonly associated with which of the following ports?

A. 25
B. 53
C. 143
D. 443

Answer: D

Explanation:
* HTTPS authenticates the website and corresponding web server with which one is communicating. HTTPS makes use of port 443.

Incorrect Options:

A: Port 25 is used by Simple Mail Transfer Protocol (SMTP) for routing e-mail between mail servers.

B: Port 53 is used by Domain Name System (DNS).

C: Port 143 is used by Internet Message Access Protocol (IMAP) for the management of email messages.

Reference:

https://en.wikipedia.org/wiki/HTTPS

https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers

CompTIA Security+ Question I-67

Which of the following would satisfy wireless network implementation requirements to use mutual authentication and usernames and passwords?

A. EAP-MD5
B. WEP
C. PEAP-MSCHAPv2
D. EAP-TLS

Answer: C

Explanation:
PEAP-MS-CHAP v2 is easier to deploy than EAP-TLS or PEAP-TLS because user authentication is accomplished via password-base credentials (user name and password) rather than digital certificates or smart cards.

CompTIA Security+ Question H-70

Company A sends a PGP encrypted file to company B. If company A used company B’s public key to encrypt the file, which of the following should be used to decrypt data at company B?

A. Registration
B. Public key
C. CRLs
D. Private key

Answer: D

Explanation:
In a PKI the sender encrypts the data using the receiver’s public key. The receiver decrypts the data using his own private key.

PKI is a two-key, asymmetric system with four main components: certificate authority (CA), registration authority (RA), RSA (the encryption algorithm), and digital certificates. Messages are encrypted with a public key and decrypted with a private key. A PKI example: You want to send an encrypted message to Jordan, so you request his public key. Jordan responds by sending you that key. You use the public key he sends you to encrypt the message. You send the message to him. Jordan uses his private key to decrypt the message.

CompTIA Security+ Question G-58

Configuring key/value pairs on a RADIUS server is associated with deploying which of the following?

A. WPA2-Enterprise wireless network
B. DNS secondary zones
C. Digital certificates
D. Intrusion detection system

Answer: A

Explanation:
WPA2-Enterprise is designed for enterprise networks and requires a RADIUS authentication server.

CompTIA Security+ Question G-47

A company’s security administrator wants to manage PKI for internal systems to help reduce costs. Which of the following is the FIRST step the security administrator should take?

A. Install a registration server.
B. Generate shared public and private keys.
C. Install a CA
D. Establish a key escrow policy.

Answer: C

Explanation:
PKI is a two-key, asymmetric system with four main components: certificate authority (CA), registration authority (RA), RSA (the encryption algorithm), and digital certificates. When you implement a PKI you should start by installing a CA.

CompTIA Security+ Question G-38

In which of the following scenarios is PKI LEAST hardened?

A. The CRL is posted to a publicly accessible location.
B. The recorded time offsets are developed with symmetric keys.
C. A malicious CA certificate is loaded on all the clients.
D. All public keys are accessed by an unauthorized user.

Answer: C

Explanation:
A rogue Certification Authority (CA) certificate allows malicious users to impersonate any Web site on the Internet, including banking and e-commerce sites secured using the HTTPS protocol. A rogue CA certificate would be seen as trusted by Web browsers, and it is harmful because it can appear to be signed by one of the root CAs that browsers trust by default. A rogue Certification Authority (CA) certificate can be created using a vulnerability in the Internet Public Key Infrastructure (PKI) used to issue digital certificates for secure Web sites.