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CompTIA Security+ Certification Certification Exam

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CompTIA SY0-401 Free Practice Questions

Q1. A Chief Information Security Officer (CISO) wants to implement two-factor authentication within the company. Which of the following would fulfill the CISO’s requirements? 

A. Username and password 

B. Retina scan and fingerprint scan 

C. USB token and PIN 

D. Proximity badge and token 

Answer:

Explanation: 

Multi-factor authentication (MFA) is a method of computer access control which a user can pass by successfully presenting authentication factors from at least two of the three categories: knowledge factors ("things only the user knows"), such as passwords possession factors ("things only the user has"), such as ATM cards inherence factors ("things only the user is"), such as biometrics 

In this question, a USB token is a possession factor (something the user has) and a PIN is a knowledge factor (something the user knows). 

Q2. Input validation is an important security defense because it: 

A. rejects bad or malformed data. 

B. enables verbose error reporting. 

C. protects mis-configured web servers. 

D. prevents denial of service attacks. 

Answer:

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. 

Q3. Which of the following components MUST be trusted by all parties in PKI? 

A. Key escrow 

B. CA 

C. Private key 

D. Recovery key 

Answer:

Explanation: 

A certificate authority (CA) is an organization that is responsible for issuing, revoking, and 

distributing certificates. In a simple trust model all parties must trust the CA. 

In a more complicated trust model all parties must trust the Root CA. 

Q4. Which of the following should a security technician implement to identify untrusted certificates? 

A. CA 

B. PKI 

C. CRL 

D. Recovery agent 

Answer:

Explanation: 

Untrusted certificates and keys are revoked and put into the CRL. Note: The CRL (Certificate revocation list) is exactly what its name implies: a list of subscribers paired with digital certificate status. The list enumerates revoked certificates along with the reason(s) for revocation. The dates of certificate issue, and the entities that issued them, are also included. 

Q5. Users need to exchange a shared secret to begin communicating securely. Which of the following is another name for this symmetric key? 

A. Session Key 

B. Public Key 

C. Private Key 

D. Digital Signature 

Answer:

Explanation: 

Explanation: Symmetric algorithms require both ends of an encrypted message to have the same key and processing algorithms. Symmetric algorithms generate a secret key that must be protected. A symmetric key, sometimes referred to as a secret key or private key, is a key that isn’t disclosed to people who aren’t authorized to use the encryption system. 

Q6. Timestamps and sequence numbers act as countermeasures against which of the following types of attacks? 

A. Smurf 

B. DoS 

C. Vishing 

D. Replay 

Answer:

Explanation: 

A replay attack (also known as playback attack) is a form of network attack in which a valid data transmission is maliciously or fraudulently repeated or delayed. This is carried out either by the originator or by an adversary who intercepts the data and retransmits it, possibly as part of a masquerade attack by IP packet substitution (such as stream cipher attack). 

For example: Suppose Alice wants to prove her identity to Bob. Bob requests her password as proof of identity, which Alice dutifully provides (possibly after some transformation like a hash function); meanwhile, Eve is eavesdropping on the conversation and keeps the password (or the hash). After the interchange is over, Eve (posing as Alice) connects to Bob; when asked for a proof of identity, Eve sends Alice's password (or hash) read from the last session, which Bob accepts thus granting access to Eve. 

Countermeasures: A way to avoid replay attacks is by using session tokens: Bob sends a one-time token to Alice, which Alice uses to transform the password and send the result to Bob (e.g. computing a hash function of the session token appended to the password). On his side Bob performs the same computation; if and only if both values match, the login is successful. Now suppose Eve has captured this value and tries to use it on another session; Bob sends a different session token, and when Eve replies with the captured value it will be different from Bob's computation. Session tokens should be chosen by a (pseudo-) random process. Otherwise Eve may be able to pose as Bob, presenting some predicted future token, and convince Alice to use that token in her transformation. Eve can then replay her reply at a later time (when the previously predicted token is actually presented by Bob), and Bob will accept the authentication. One-time passwords are similar to session tokens in that the password expires after it has been used or after a very short amount of time. They can be used to authenticate individual transactions in addition to sessions. The technique has been widely implemented in personal online banking systems. Bob can also send nonces but should then include a message authentication code (MAC), which Alice should check. Timestamping is another way of preventing a replay attack. Synchronization should be achieved using a secure protocol. For example Bob periodically broadcasts the time on his clock together with a MAC. When Alice wants to send Bob a message, she includes her best estimate of the time on his clock in her message, which is also authenticated. Bob only accepts messages for which the timestamp is within a reasonable tolerance. The advantage of this scheme is that Bob does not need to generate (pseudo-) random numbers, with the trade-off being that replay attacks, if 

they are performed quickly enough i.e. within that 'reasonable' limit, could succeed. 

Q7. Which of the following types of logs could provide clues that someone has been attempting to compromise the SQL Server database? 

A. Event 

B. SQL_LOG 

C. Security 

D. Access 

Answer:

Explanation: 

Event logs include Application logs, such as those where SQL Server would write entries. This is where you would see logs with details of someone trying to access a SQL database. 

Q8. Which of the following would be MOST appropriate to secure an existing SCADA system by preventing connections from unauthorized networks? 

A. Implement a HIDS to protect the SCADA system 

B. Implement a Layer 2 switch to access the SCADA system 

C. Implement a firewall to protect the SCADA system 

D. Implement a NIDS to protect the SCADA system 

Answer:

Explanation: 

Q9. A new MPLS network link has been established between a company and its business partner. 

The link provides logical isolation in order to prevent access from other business partners. Which of the following should be applied in order to achieve confidentiality and integrity of all data across the link? 

A. MPLS should be run in IPVPN mode. 

B. SSL/TLS for all application flows. 

C. IPSec VPN tunnels on top of the MPLS link. 

D. HTTPS and SSH for all application flows. 

Answer:

Explanation: 

IPSec can very well be used with MPLS. IPSec could provide VPN tunnels on top if the MPLS link. Internet Protocol Security (IPSec) isn’t a tunneling protocol, but it’s used in conjunction with tunneling protocols. IPSec is oriented primarily toward LAN-to-LAN connections, but it can also be used with dial-up connections. IPSec provides secure authentication and encryption of data and headers; this makes it a good choice for security. 

Q10. A company’s chief information officer (CIO) has analyzed the financial loss associated with the company’s database breach. They calculated that one single breach could cost the company $1,000,000 at a minimum. Which of the following documents is the CIO MOST likely updating? 

A. Succession plan 

B. Continuity of operation plan 

C. Disaster recovery plan 

D. Business impact analysis 

Answer:

Explanation: 

Business impact analysis (BIA) is the process of evaluating all of the critical systems in an organization to define impact and recovery plans. BIA isn’t concerned with external threats or vulnerabilities; the analysis focuses on the impact a loss would have on the organization. A BIA comprises the following: identifying critical functions, prioritizing critical business functions, calculating a timeframe for critical systems loss, and estimating the tangible impact on the organization. 

Q11. Which of the following is BEST carried out immediately after a security breach is discovered? 

A. Risk transference 

B. Access control revalidation 

C. Change management 

D. Incident management 

Answer:

Explanation: 

Incident management is the steps followed when security incident occurs. 

Q12. An organizations' security policy requires that users change passwords every 30 days. After a security audit, it was determined that users were recycling previously used passwords. Which of the following password enforcement policies would have mitigated this issue? 

A. Password history 

B. Password complexity 

C. Password length 

D. Password expiration 

Answer:

Explanation: 

Q13. The call center supervisor has reported that many employees have been playing preinstalled games on company computers and this is reducing productivity. 

Which of the following would be MOST effective for preventing this behavior? 

A. Acceptable use policies 

B. Host-based firewalls 

C. Content inspection 

D. Application whitelisting 

Answer:

Explanation: 

Application whitelisting is a form of application security which prevents any software from running on a system unless it is included on a preapproved exception list. 

Q14. Datacenter access is controlled with proximity badges that record all entries and exits from the datacenter. The access records are used to identify which staff members accessed the data center in the event of equipment theft. Which of the following MUST be prevented in order for this policy to be effective? 

A. Password reuse 

B. Phishing 

C. Social engineering 

D. Tailgating 

Answer:

Explanation: 

Tailgating is the term used for someone being so close to you when you enter a building that they are able to come in right behind you without needing to use a key, a card, or any other security device. This should be prevented in this case. 

Q15. Which of the following is best practice to put at the end of an ACL? 

A. Implicit deny 

B. Time of day restrictions 

C. Implicit allow 

D. SNMP string 

Answer:

Explanation: 

An implicit deny clause is implied at the end of each ACL. This implies that if you aren’t specifically granted access or privileges for a resource, you’re denied access by default. The implicit deny clause is set by the system.