New Release CS0-002 CompTIA CySA+ Questions

The grep command is a tool that searches for a pattern of characters in a file or input and prints the matching lines1 The egrep command is a variant of grep that supports extended regular expressions, which allow more complex and flexible pattern matching2 The more command is a filter that displays the contents of a file or input one screen at a time3 The pipe symbol (|) is used to redirect the output of one command to the input of another command. The redirection symbol (>) is used to redirect the output of a command to a file.

The command given in option C performs the following steps:

• It uses the more command to display the contents of the webserver.log file.
• It pipes the output of the more command to the grep command, which searches for lines that contain ‘*.xls’, which is a pattern that matches any file name ending with .xls (a spreadsheet file extension).
• It pipes the output of the grep command to the egrep command, which searches for lines that contain ‘return=200’, which is a pattern that matches any HTTP status code of 200 (which indicates a successful request).
• It redirects the output of the egrep command to a file named accessreport.txt, which contains the date, time, and IP address associated with any spreadsheet downloads.

The single loss expectancy (SLE) is a measure of the monetary loss associated with a single occurrence of a risk. The SLE can be calculated by multiplying the asset value (AV) by the exposure factor (EF), which is the percentage of loss that the asset would suffer if the risk occurred. In this case, the asset value is the revenue generated by the service, which is $1,000. The exposure factor is the impact of the attack on the server’s capacity, which is 20%. Therefore, the SLE is $1,000 x 0.2 = $2001.

Disabling error messaging for authentication would be the best recommendation to decrease the likelihood that a malicious attacker will receive helpful information. Error messaging for authentication is a feature that displays an error message when a user enters an incorrect username or password. However, this feature can also provide useful information to an attacker who is trying to guess or brute-force valid credentials. For example, if the error message says “incorrect password for given username”, then the attacker knows that the username is valid and only needs to focus on cracking the password. Disabling error messaging for authentication can help reduce this information leakage and make it harder for an attacker to succeed.