CompTIA Updated CAS-004 Exam Questions and Answers by dougie

The browser is the application that the security analyst should patch first, given that all the applications have equally high CVSS scores. CVSS stands for Common Vulnerability Scoring System, which is a method for measuring the severity of vulnerabilities based on various factors, such as access conditions, impact, and exploitability. CVSS scores range from 0 to 10, with higher scores indicating higher severity. However, CVSS scores alone are not sufficient to determine the patching priority, as they do not account for other factors, such as the likelihood of exploitation, the exposure of the system, or the criticality of the data. Therefore, the security analyst should also consider the context and the risk of each application when deciding which one to patch first. In this case, the browser is likely to be the most exposed and frequently used application by the network administrator, and also the most likely entry point for an attacker to compromise the system or access the SSO web portal. Therefore, patching the browser first can reduce the risk of a successful attack and protect the system and the data from further damage. Verified References:

https://nvd.nist.gov/vuln-metrics/cvss

https://www.darkreading.com/risk/vulnerability-severity-scores-make-for-poor-patching-priority-researchers-find

A regular expression (regex) is a sequence of characters that defines a search pattern for matching text. A regex can be used to detect the presence of a malicious piece of software communicating with its command-and-control server by matching the indicators of compromise (IOC) in the network traffic.

In this case, the systems administrator should use the regex Host: [a-z]*.malicious.com to determine if any of the company hosts are compromised, while reducing false positives, because this regex would:

Match the Host header in the HTTP request, which specifies the domain name of the command-and-control server.

Allow any subdomain under the malicious.com domain, by using the character class [a-z]*, which matches zero or more lowercase letters.

Escape the dot character in the domain name, by using the backslash , which prevents it from being interpreted as a wildcard that matches any character.

Not match any other parts of the IOC that could change, such as the URL path, the User-Agent header, or the HTTP method.

The analyst should implement every solution one at a time in a virtual lab, running an attack simulation each time while collecting metrics. Roll back each solution and then implement the next. Choose the best solution based on the best metrics. This approach would allow the analyst to test each solution individually and measure its effectiveness against the attack, without affecting the other solutions or the production environment. This would also minimize the downtime required to implement the best solution, as only one change would be needed. The other options would either involve implementing multiple solutions at once, which could cause conflicts or errors, or collecting metrics before running the attack simulation, which would not reflect the actual impact of the solutions.

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 applications to 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.