Free CompTIA CAS-004 Practice Exam with Questions & Answers | Set: 2

OPC (Open Platform Communications) and Modbus are two common protocols used for industrial control systems (ICS). OPC is a standard that allows different devices and applicationsto exchange data in a vendor-neutral way. Modbus is a serial communication protocol that enables devices to send and receive commands and data over a network. Modbus has two variants: Modbus TCP/IP, which uses TCP port 502 for communication, and Modbus RTU/ASCII, which uses serial ports.

To allow an OPC server to communicate with a Modbus server that is controlling electrical relays, the security engineer should recommend restricting inbound traffic so that only the OPC server is permitted to reach the Modbus server on port 502. This configuration would:

Permit the OPC server to send commands and data to the Modbus server using Modbus TCP/IP protocol over port 502.

Limit operational disruptions, by preventing unauthorized or malicious access to the Modbus server from other sources.

Due to the limitations within the Modbus protocol, such as lack of encryption and authentication, restricting inbound traffic is a necessary security measure to protect the integrity and availability of the ICS.

Rules of engagement are legal documents that should be signed by all parties involved in an assessment to ensure they understand their roles and responsibilities. Rules of engagement define the scope, objectives, methods, deliverables, limitations, and expectations of an assessment project. They also specify the legal and ethical boundaries, communication channels, escalation procedures, and reporting formats for the assessment. Rules of engagement help to avoid misunderstandings, conflicts, or liabilities during or after an assessment.

 DLP, or data loss prevention, and CASB, or cloud access security broker, are the solutions that when installed and configured would best meet the CSO’s requirements. DLP is a technology that monitorsand prevents unauthorized or accidental data leakage or exfiltration from an organization’s network or devices. DLP can use document attributes, such as metadata, keywords, or fingerprints, to identify and classify sensitive data and enforce policies on how they can be accessed, transferred, or shared. CASB is a technology that acts as a proxy or intermediary between an organization’s cloud services and its users. CASB can provide visibility, compliance, threat protection, and data security for cloud-based applications and data. CASB can also prevent on-site staff from accessing personal SaaS solutions that are not authorized by the organization.

A risk associated with SDN is the expanded attack surface that it introduces. SDN is a network architecture that decouples the control plane from the data plane, allowing centralized and programmable management of network devices and traffic. However, this also exposes new attack vectors and vulnerabilities that can compromise the security and performance of the network. For example, an attacker can target the SDN controller, which is the core component that communicates with and controls the network devices. A successful attack on the SDN controller can result in denial of service, unauthorized access, data leakage, or network hijacking. An attacker can also exploit the communication channels between the SDN controller and the network devices, such as the OpenFlow protocol, to intercept, modify, or inject malicious messages or commands. Additionally, an attacker can leverage malicious or compromised applications that run on top of the SDN controller to manipulate or disrupt the network behavior. Verified References:

https://www.isaca.org/resources/isaca-journal/issues/2016/volume-4/benefits-and-the-security-risk-of-software-defined-networking

https://link.springer.com/article/10.1007/s40860-022-00171-8

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 organization’s new email system should provide e-discovery functionality. E-discovery stands for electronic discovery, which is the process of identifying, preserving, collecting, processing, reviewing, analyzing, and producing electronically stored information (ESI) that is relevant to a legal matter. E-discovery can help the organization comply with legal holds, which are orders or notices to preserve relevant ESI when litigation is anticipated or ongoing. E-discovery can also help the organization reduce the costs and risks of litigation, as well as improve the efficiency and accuracy of the discovery process. Verified References:

https://www.techtarget.com/searchsecurity/definition/electronic-discovery

https://www.techtarget.com/searchsecurity/definition/legal-hold

https://www.ibm.com/topics/electronic-discovery

WPA3-Personal is a simple, secure solution for a small business with a single access point. It uses a new security protocol called Simultaneous Authentication of Equals (SAE), which replaces the Pre-Shared Key (PSK) exchange with a more secure way to do initial key exchange. SAE also provides forward secrecy, which means that even if the password is compromised, the attacker cannot decrypt past or future data. WPA3-Personal also uses AES-128 in CCM mode as the minimum encryption algorithm, which is resistant to offline password attacks. WPA3-Personal requires low administrative overhead and supports a single SSID with no guest access. Verified References:

https://www.diffen.com/difference/WPA2_vs_WPA3

https://www.thewindowsclub.com/wpa3-personal-enterprise-wi-fi-encryption

https://www.teldat.com/blog/wpa3-wi-fi-network-security-wpa3-personal-wpa3-enterprise/

The most likely cause of the signature failing is that the certificate is set for the wrong key usage. Key usage is an extension of a certificate that defines the purpose and functionality of the public key contained in the certificate. Key usage can include digital signature, key encipherment, dataencipherment, certificate signing, and others. If the certificate is set for a different key usage than digital signature, it will not be able to sign the applications properly. The administrator should check the key usage extension of the certificate and make sure it matches the intended purpose. Verified References:

https://www.wintips.org/how-to-fix-windows-cannot-verify-the-digital-signature-for-this-file-error-in-windows-8-7-vista/

https://softwaretested.com/mac/how-to-fix-a-digital-signature-error-on-windows-10/

https://support.microsoft.com/en-us/office/digital-signatures-and-certificates-8186cd15-e7ac-4a16-8597-22bd163e8e96

Wireless network auto joining is the mobile configuration setting that the mobile administrator is verifying by reviewing the mobile device DHCP logs. Wireless network auto joining is a feature that allows mobile devices to automatically connect to a predefined wireless network without requiring user intervention or authentication. This can be useful for corporate or trusted networks that need frequent access by mobile devices. The DHCP logs show that the mobile devices are assigned IP addresses from the wireless network with SSID “CorpWiFi”, which indicates that they are auto joining this network.

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/

Executing the files in the sandbox on the web proxy is the best solution to reduce the risk of employees downloading and opening malicious files from the internet. A sandbox is a secure and isolated environment that can run untrusted or potentially harmful code without affecting the rest of the system. By executing the files in the sandbox, the web proxy can analyze their behavior and detect any malicious activity before allowing them to reach the corporate workstations.

The company should implement an EV certificate and HSTS on its new website. An EV certificate provides the highest level of web identity validation by requiring extensive verification of the organization’s identity and domain ownership. HSTS enforces encryption of all web transactions by redirecting HTTP requests to HTTPS and preventing users from accepting invalid certificates. These solutions would enhance the security and trustworthiness of the website without increasing complexity or expenditure significantly. Verified References:

https://www.entrust.com/digital-security/certificate-solutions/products/digital-certificates/tls-ssl-certificates

https://learn.microsoft.com/en-us/azure/active-directory/develop/access-tokens

WAP A: No issue found. The WAP A is configured correctly and meets the requirements.

PC A = Enable host-based firewall to block all traffic

This option will turn off the host-based firewall and allow all traffic to pass through. This will comply with the requirement and also improve the connectivity of PC A to other devices on the network. However, this option will also reduce the security of PC A and make it more vulnerable to attacks. Therefore, it is recommended to use other security measures, such as antivirus, encryption, and password complexity, to protect PC A from potential threats.

Laptop A: Patch management

This option will install the updates that are available for Laptop A and ensure that it has the most recent security patches and bug fixes. This will comply with the requirement and also improve the performance and stability of Laptop A. However, this option may also require a reboot of Laptop A and some downtime during the update process. Therefore, it is recommended to backup any important data and close any open applications before applying the updates.

Switch A: No issue found. The Switch A is configured correctly and meets the requirements.

Switch B: No issue found. The Switch B is configured correctly and meets the requirements.

Laptop B: Disable unneeded services

This option will stop and disable the telnet service that is using port 23 on Laptop B. Telnet is a cleartext service that transmits data in plain text over the network, which exposes it to eavesdropping, interception, and modification by attackers. By disabling the telnet service, you will comply with the requirement and also improve the security of Laptop B. However, this option may also affect the functionality of Laptop B if it needs to use telnet for remote administration or other purposes. Therefore, it is recommended to use a secure alternative to telnet, such as SSH or HTTPS, that encrypts the data in transit.

PC B: Enable disk encryption

This option will encrypt the HDD of PC B using a tool such as BitLocker or VeraCrypt. Disk encryption is a technique that protects data at rest by converting it into an unreadable format that can only be decrypted with a valid key or password. By enabling disk encryption, you will comply with the requirement and also improve the confidentiality and integrity of PC B’s data. However, this option may also affect the performance and usability of PC B, as it requires additional processing time and user authentication to access the encrypted data. Therefore, it is recommended to backup any important data and choose a strong key or password before encrypting the disk.

PC C: Disable unneeded services

This option will stop and disable the SSH daemon that is using port 22 on PC C. SSH is a secure service that allows remote access and command execution over an encrypted channel. However, port 22 is the default and well-known port for SSH, which makes it a common target for brute-force attacks and port scanning. By disabling the SSH daemon on port 22, you will comply with the requirement and also improve the security of PC C. However, this option may also affect the functionality of PC C if it needs to use SSH for remote administration or other purposes. Therefore, it is recommended to enable the SSH daemon on a different port, such as 4022, by editing the configuration file using the following command:

sudo nano /etc/ssh/sshd_config

Server A. Need to select the following:

The process that involves searching and collecting evidence during an investigation or lawsuit is e-discovery. E-discovery stands for electronic discovery, which is the process of identifying, preserving, collecting, processing, reviewing, analyzing, and producing electronically stored information (ESI) that is relevant to a legal matter. E-discovery can be used for civil litigation, criminal prosecution, regulatory compliance, internal investigations, and other purposes. E-discovery can help parties obtain evidence from various sources, such as emails, documents, databases, social media, cloud services, mobile devices, and others. Verified References:

https://www.techtarget.com/searchsecurity/definition/electronic-discovery

https://www.edrm.net/frameworks-and-standards/edrm-model/

https://www.law.cornell.edu/wex/electronic_discovery_(federal)

The root cause of this issue is that the iOS keychain imported only the client public and private keys, but not the CA certificate. A PKCS#12 file (.p12 or .pfx) is a file format that contains a certificate and its private key, optionally protected by a password. A PKCS#12 file can also contain intermediate certificates or root certificates that are needed to verify the certificate chain. However, when importing a PKCS#12 file into the iOS keychain, only the certificate and its private key are imported, not the CA certificate. This means that the iOS device cannot verify the authenticity of the certificate, and displays the error message “mbedTLS: ca certificate undefined”. To fix this issue, the CA certificate needs to be imported separately into the iOS keychain, either manually or using a configuration profile. Verified References:

https://developer.apple.com/documentation/devicemanagement/certificatepkcs12

https://support.apple.com/guide/deployment/distribute-certificates-depcdc9a6a3f/web

https://openvpn.net/faq/how-do-i-use-a-client-certificate-and-private-key-from-the-ios-keychain/