CompTIA Security+ Question E-80

Peter must send Ann a message and provide Ann with assurance that he was the actual sender. Which of the following will Peter need to use to BEST accomplish the objective?

A. A pre-shared private key
B. His private key
C. Ann’s public key
D. His public key

Answer: B

Explanation:
To achieve both authentication and confidentiality, Peter should include Ann’s name in the message, sign it using his private key, and then encrypt both the message and the signature using Ann’s public key.

CompTIA Security+ Question E-79

Methods to test the responses of software and web applications to unusual or unexpected inputs are known as:

A. Brute force.
B. HTML encoding.
C. Web crawling.
D. Fuzzing.

Answer: D

Explanation:
Fuzzing is a software testing technique that involves providing invalid, unexpected, or random data to as inputs to a computer program. The program is then monitored for exceptions such as crashes, or failed validation, or memory leaks.

CompTIA Security+ Question E-78

Peter needs to track employees who log into a confidential database and edit files. In the past, critical files have been edited, and no one admits to making the edits. Which of the following does Peter need to implement in order to enforce accountability?

A. Non-repudiation
B. Fault tolerance
C. Hashing
D. Redundancy

Answer: C

CompTIA Security+ Question E-77

Elastic cloud computing environments often reuse the same physical hardware for multiple customers over time as virtual machines are instantiated and deleted. This has important implications for which of the following data security concerns?

A. Hardware integrity
B. Data confidentiality
C. Availability of servers
D. Integrity of data

Answer: B

Explanation:
Data that is not kept separate or segregated will impact on that data’s confidentiality maybe being compromised. Be aware of the fact that your data is only as safe as the data with which it is integrated. For example, assume that your client database is hosted on a server that another company is also using to test an application that they are creating. If their application obtains root-level access at some point (such as to change passwords) and crashes at that point, then the user running the application could be left with root permissions and conceivably be to access data on the server for which they are not authorized, such as your client database. Data segregation is crucial; keep your data on secure servers.

CompTIA Security+ Question E-76

Ann is the data owner of financial records for a company. She has requested that she have the ability to assign read and write privileges to her folders. The network administrator is tasked with setting up the initial access control system and handing Ann’s administrative capabilities. Which of the following systems should be deployed?

A. Role-based
B. Mandatory
C. Discretionary
D. Rule-based

Answer: C

Explanation:
In a Discretionary Access Control (DAC) model, network users have some fl exibility regarding how information is accessed. This model allows users to share information dynamically with other users. Discretionary access control (DAC) allows access to be granted or restricted by an object’s owner based on user identity and on the discretion of the object owner. In this question, Ann has requested that she have the ability to assign read and write privileges to her folders. Read and write access to Ann’s files will be granted by Ann at her discretion. Therefore, this is an example of Discretionary Access Control.

CompTIA Security+ Question E-75

A technician wants to implement a dual factor authentication system that will enable the organization to authorize access to sensitive systems on a need-to-know basis. Which of the following should be implemented during the authorization stage?

A. Biometrics
B. Mandatory access control
C. Single sign-on
D. Role-based access control

Answer: A

Explanation:
This question is asking about “authorization”, not authentication.

Mandatory access control (MAC) is a form of access control commonly employed by government and military environments. MAC specifies that access is granted based on a set of rules rather than at the discretion of a user. The rules that govern MAC are hierarchical in nature and are often called sensitivity labels, security domains, or classifications.

MAC can also be deployed in private sector or corporate business environments. Such cases typically involve the following four security domain levels (in order from least sensitive to most sensitive):

Public Sensitive Private Confidential

A MAC environment works by assigning subjects a clearance level and assigning objects a sensitivity label—in other words, everything is assigned a classification marker. Subjects or users are assigned clearance levels. The name of the clearance level is the same as the name of the sensitivity label assigned to objects or resources. A person (or other subject, such as a program or a computer system) must have the same or greater assigned clearance level as the resources they wish to access. In this manner, access is granted or restricted based on the rules of classification (that is, sensitivity labels and clearance levels). MAC is named as it is because the access control it imposes on an environment is mandatory. Its assigned classifications and the resulting granting and restriction of access can’t be altered by users. Instead, the rules that define the environment and judge the assignment of sensitivity labels and clearance levels control authorization. MAC isn’t a very granularly controlled security environment. An improvement to MAC includes the use of need to know: a security restriction where some objects (resources or data) are restricted unless the subject has a need to know them. The objects that require a specific need to know are assigned a sensitivity label, but they’re compartmentalized from the rest of the objects with the same sensitivity label (in the same security domain). The need to know is a rule in and of itself, which states that access is granted only to users who have been assigned work tasks that require access to the cordoned-off object. Even if users have the proper level of clearance, without need to know, they’re denied access. Need to know is the MAC equivalent of the principle of least privilege from DAC

CompTIA Security+ Question E-74

A security administrator must implement a system to allow clients to securely negotiate encryption keys with the company’s server over a public unencrypted communication channel.
Which of the following implements the required secure key negotiation? (Select TWO).

A. PBKDF2
B. Symmetric encryption
C. Steganography
D. ECDHE
E. Diffie-Hellman

Answer: D,E

Explanation:
Elliptic curve Diffie–Hellman (ECDH) is an anonymous key agreement protocol that allows two parties, each having an elliptic curve public-private key pair, to establish a shared secret over an insecure channel. This shared secret may be directly used as a key, or better yet, to derive another key which can then be used to encrypt subsequent communications using a symmetric

key cipher. It is a variant of the Diffie–Hellman protocol using elliptic curve cryptography. Note: Adding an ephemeral key to Diffie-Hellman turns it into DHE (which, despite the order of the acronym, stands for Ephemeral Diffie-Hellman). Adding an ephemeral key to Elliptic Curve Diffie-Hellman turns it into ECDHE (again, overlook the order of the acronym letters; it is called Ephemeral Elliptic Curve Diffie-Hellman). It is the ephemeral component of each of these that provides the perfect forward secrecy.

CompTIA Security+ Question E-73

Which of the following is a common coding error in which boundary checking is not performed?

A. Input validation
B. Fuzzing
C. Secure coding
D. Cross-site scripting

Answer: A

Explanation:
Input validation is a defensive technique intended to mitigate against possible user input attacks, such as buffer overflows and fuzzing. Input validation checks every user input submitted to the application before processing that input. The check could be a length, a character type, a language type, or a domain.

CompTIA Security+ Question E-72

A network administrator, Peter, arrives at his new job to find that none of the users have changed their network passwords since they were initially hired. Peter wants to have everyone change their passwords immediately. Which of the following policies should be enforced to initiate a password change?

A. Password expiration
B. Password reuse
C. Password recovery
D. Password disablement

Answer: A

Explanation:
The Maximum password age policy setting determines the number of days that a password can be used before the system requires the user to change it. The password expiration setting determines that a user will not be able to log into a system without changing their password after the maximum password age has been reached.

CompTIA Security+ Question E-71

Fuzzing is a security assessment technique that allows testers to analyze the behavior of software applications under which of the following conditions?

A. Unexpected input
B. Invalid output
C. Parameterized input
D. Valid output

Answer: A

Explanation:
Fuzzing is a software testing technique that involves providing invalid, unexpected, or random data to as inputs to a computer program. The program is then monitored for exceptions such as crashes, or failed validation, or memory leaks.