CompTIA CAS-004 - CompTIA SecurityX Certification Exam

If on VPN concentrator goes down due to a zero day threat, having a redundant VPN concentrator of a different vendor should keep you going.

Configuring user settings in Group Policy is the best way for an administrator to implement the decision to restrict PowerShell access to only administrators. Group Policy is a feature of Windows that allows administrators to manage and enforce settings for users and computers in a domain. By using Group Policy, an administrator can create a policy that blocks or disables PowerShell for all users except for a particular group, such as administrators. This policy can be applied to all computers in the domain or to specific organizational units. This method is more effective and manageable than uninstalling PowerShell, monitoring event logs, providing user education, or blocking PowerShell via HIDS. Verified References:

https://www.windowscentral.com/how-disable-powershell-windows-10

https://learn.microsoft.com/en-us/answers/questions/195218/how-to-restrict-powershell-for-all-users-except-fo

https://windowsloop.com/block-disable-powershell/

Cipher feedback (CFB) is a mode of operation for block ciphers that allows them to encrypt streaming data. CFB uses an initialization vector (IV) and a block cipher to generate a keystream that is XORed with the plaintext to produce the ciphertext. CFB has low latency because it can encrypt each byte or bit of plaintext as soon as it arrives, without waiting for a full block. CFB is suitable for streaming data because it does not require padding or block synchronization.

B. Cipher block chaining message authentication code (CBC-MAC) is a mode of operation for block ciphers that provides both encryption and authentication. CBC-MAC uses an IV and a block cipher toencrypt the plaintext and generate a MAC value that is appended to the ciphertext. CBC-MAC has high latency because it requires the entire message to be processed before generating the MAC value. CBC-MAC is not suitable for streaming data because it requires padding and block synchronization.

C. Cipher block chaining (CBC) is a mode of operation for block ciphers that provides encryption only. CBC uses an IV and a block cipher to encrypt each block of plaintext by XORing it with the previous ciphertext block. CBC has high latency because it requires a full block of plaintext before encryption. CBC is not suitable for streaming data because it requires padding and block synchronization.

D. Electronic codebook (ECB) is a mode of operation for block ciphers that provides encryption only. ECB uses a block cipher to encrypt each block of plaintext independently. ECB has low latency because it can encrypt each block of plaintext as soon as it arrives. However, ECB is not suitable for streaming data because it requires padding and block synchronization. Moreover, ECB is insecure because it does not use an IV and produces identical ciphertext blocks for identical plaintext blocks.

Input validation is a technique that checks the user input for any errors, malicious data, or unexpected values before processing it by the application. Input validation can prevent many common web application attacks, such as:

SQL injection, which exploits a vulnerability in the application’s database query to execute malicious SQL commands.

Cross-site scripting (XSS), which injects malicious JavaScript code into the application’s web page to execute on the client-side browser.

Directory traversal, which accesses files or directories outside of the intended scope by manipulating the file path.

In this case, the security engineer should recommend input validation as the best mitigation technique, because it would:

Prevent the exfiltration of a company report by validating the file parameter in the URL and ensuring that it matches a predefined list of allowed files or formats.

Enhance the security of the web application by filtering out any malicious or invalid input from users or attackers.

Be more effective and efficient than other techniques, such as firewall, WAF (Web Application Firewall), or DLP (Data Loss Prevention), which may not be able to detect or block all types of web application attacks.

The developer would most likely implement a Root CA in the autonomous vehicle’s software. A Root CA is the top-level authority in a PKI that issues and validates certificates for subordinate CAs or end entities. A Root CA can be self-signed and embedded in the vehicle’s software, which would reduce the need for external communication and verification. A Root CA would also enable the vehicle to use digital signatures and encryption for secure communication with other vehicles or infrastructure. Verified References:

https://cse.iitkgp.ac.in/~abhij/publications/PKI++.pdf

https://www.digicert.com/blog/connected-cars-need-security-use-pki

https://ieeexplore.ieee.org/document/9822667/

Purchasing one wildcard certificate is the best solution to protect multiple websites hosted by an organization in a cloud-hosted WAF. A wildcard certificate is a type of SSL/TLS certificate thatcan secure a domain name and any number of its subdomains with a single certificate. For example, a wildcard certificate for *.mycompany.com can secure www.mycompany.com, campus.mycompany.com, and any other subdomain under mycompany.com. A wildcard certificate can save costs and simplify management compared to purchasing individual certificates for each website.

SD-WAN (Software-Defined Wide Area Network) is a technology that allows organizations to use multiple, low-cost Internet connections to create a secure and dynamic WAN. SD-WAN can provide benefits such as lower costs, higher performance, and easier management compared to traditional WAN technologies, such as MPLS (Multiprotocol Label Switching).

However, SD-WAN also introduces some potential risks, such as:

The reliability and security of the Internet connections, which may vary depending on the location, provider, and traffic conditions.

The compatibility and interoperability of the SD-WAN hardware and software, which may come from different vendors or use different standards.

The availability and quality of the SD-WAN provider’s support, which may depend on the provider’s size, reputation, and outsourcing practices.

In this case, the CISO would most likely identify the risk that the SD-WAN provider uses a third party for support, because this could:

Affect the organization’s ability to resolve issues or request changes in a timely and effective manner.

Expose the organization’s network data and configuration to unauthorized or malicious parties.

Increase the complexity and uncertainty of the SD-WAN service level agreement (SLA) and contract terms.

DMARC (Domain-based Message Authentication, Reporting and Conformance) and SPF (Sender Policy Framework) are two mechanisms that can help detect and prevent email spoofing, which is the creation of email messages with a forged sender address. DMARC allows a domain owner to publish a policy that specifies how receivers should handle messages that fail authentication tests, such as SPF or DKIM (DomainKeys Identified Mail). SPF allows a domain owner to specify which mail servers are authorized to send email on behalf of their domain. By checking the DMARC and SPF records of the sender’s domain, a receiver can verify if the email is from a legitimate source or not. Verified References:

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

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

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

A downgrade attack is a type of man-in-the-middle attack that forces two hosts to use an older or weaker version of the TLS protocol or its parameters. The attacker does this by replacing or deleting the STARTTLS command or exploiting the compatibility features of the protocol. The purpose of the attack is to create a pathway for enabling a cryptographic attack that would not be possible in case of a connection that is encrypted over the latest version of TLS protocol. The IOC shows that most client connections are renegotiated after establishing the connections, which could indicate that an entity is performing downgrade attacks on path by interfering with the initial handshake and making the client and server agree on a lower version of TLS or a weaker cipher suite. Verified References:

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

https://crypto.stackexchange.com/questions/10493/why-is-tls-susceptible-to-protocol-downgrade-attacks

https://venafi.com/blog/preventing-downgrade-attacks/

Law enforcement officials informed an organization that an investigation has begun. Which of the following is the FIRST step the organization should take?

Initiate a legal hold.

Refer to the retention policy

Perform e-discovery.

Review the subpoena

Answer: A

A legal hold is a process by which an organization instructs its employees or other relevant parties to preserve specific data for potential litigation. A legal hold is triggered when litigation is reasonablyanticipated, such as when law enforcement officials inform an organization that an investigation has begun. The first step the organization should take is to initiate a legal hold to ensure that relevant evidence is not deleted, destroyed, or altered. A legal hold also demonstrates the organization’s good faith and compliance with its duty to preserve evidence. Verified References:

https://percipient.co/litigation-hold-triggers-and-the-duty-to-preserve-evidence/

https://www.everlaw.com/blog/ediscovery-best-practices/guide-to-legal-holds/

In a shared responsibility model for PaaS, the customer’s responsibility is OS security. PaaS stands for Platform as a Service, which is a cloud service model that provides a platform for customers to develop, run, and manage applications without having to deal with the underlying infrastructure. The cloud provider is responsible for the physical security, network security, and host infrastructure of the platform, while the customer is responsible for the security of the operating system, the application, and the data. The customer needs to ensure that the operating system is patched, configured, and protected from malware and unauthorized access. Verified References:

https://learn.microsoft.com/en-us/azure/security/fundamentals/shared-responsibility

https://www.techtarget.com/searchcloudcomputing/feature/The-cloud-shared-responsibility-model-for-IaaS-PaaS-and-SaaS

https://www.splunk.com/en_us/blog/learn/shared-responsibility-model.html

Homomorphic encryption is a type of encryption method that allows computations to be performed on encrypted data without first decrypting it with a secret key. The results of the computations also remain encrypted and can only be decrypted by the owner of the private key. Homomorphic encryption can be used for privacy-preserving outsourced storage and computation. This means that data can be encrypted and sent to a cloud service provider (CSP) for processing, without revealing any information to the CSP or anyone else who might intercept the data. Homomorphic encryption can enable new services and applications that require processing confidential data on a large number of resources, such as machine learning, data analytics, health care, finance, and voting.

A. Processing data on a server after decrypting in order to prevent unauthorized access in transit is not a common use case for homomorphic encryption, because it does not take advantage of the main feature of homomorphic encryption, which is computing over encrypted data. This use casecan be achieved by using any standard encryption method that provides confidentiality for data in transit.

B. Maintaining the confidentiality of data both at rest and in transit to and from a CSP for processing is not a common use case for homomorphic encryption, because it does not take advantage of the main feature of homomorphic encryption, which is computing over encrypted data. This use case can be achieved by using any standard encryption method that provides confidentiality for data at rest and in transit.

D. Storing proprietary data across multiple nodes in a private cloud to prevent access by unauthenticated users is not a common use case for homomorphic encryption, because it does not involve any computation over encrypted data. This use case can be achieved by using any standard encryption method that provides confidentiality for data at rest.

https://www.splunk.com/en_us/blog/learn/homomorphic-encryption.html

https://research.aimultiple.com/homomorphic-encryption/

The security analyst acknowledges this alert because it is a false positive. A false positive is an event classification that indicates a benign or normal activity is mistakenly flagged as malicious or suspicious by the SIEM system. A false positive can occur due to misconfigured rules, outdated signatures, or faulty algorithms. A false positive can waste the security analyst’s time and resources, so it is important to acknowledge and dismiss it after verifying that it is not a real threat. Verified References:

https://www.ibm.com/topics/siem

https://www.microsoft.com/en-us/security/business/security-101/what-is-siem

https://www.splunk.com/en_us/data-insider/what-is-siem.html

The company should use an additional layer of encryption to secure the data from theft when moving to a CSP. Encryption is a process of transforming data into an unreadable format using a secret key. Encryption can protect the data from unauthorized access or modification during transit and at rest. Encryption can be applied at different levels, such as disk, file, or application. An additional layer of encryption can provide an extra security measure on top of the encryption provided by the CSP. Verified References:

https://learn.microsoft.com/en-us/partner-center/transition-seat-based-services

https://cloud.google.com/architecture/patterns-for-connecting-other-csps-with-gcp

The administrator should use SAN certificates to support multiple domain names while minimizing the amount of certificates needed. SAN stands for Subject Alternative Name, which is an extension of a certificate that allows it to include multiple fully-qualified domain names (FQDNs) within the same certificate. For example, a SAN certificate can secure www.example.com, www.example.net, and mail.example.org with one certificate. SANcertificates can reduce the cost and complexity of managing multiple certificates for different domains. SAN certificates can also support wildcard domains, such as *.example.com, which can cover any subdomain under that domain. Verified References:

https://www.techtarget.com/searchsecurity/definition/Subject-Alternative-Name

https://www.techtarget.com/searchsecurity/definition/wildcard-certificate

https://www.nexcess.net/help/what-is-a-multi-domain-ssl-certificate/