System Hacking

Correct Answer: Create a proof-of-concept that triggers the backdoor on a test system, capturing evidence like screenshots of shell access, but limiting commands to non-destructive system information gathering

As a Certified Ethical Hacker, the most appropriate approach to ethically exploit the vsftpd 2.3.4 backdoor vulnerability would be to create a proof-of-concept on a test system, capturing evidence like screenshots of shell access, while limiting commands to non-destructive system information gathering. This approach demonstrates the vulnerability in a controlled environment, provides clear evidence of the risk, and avoids any negative impact on production systems. This aligns with ethical hacking principles of doing no harm while effectively communicating security risks. The other approaches are inappropriate because: - Executing the exploit on a production server, even during off-hours, poses unnecessary risk to patient data and critical healthcare systems. This could violate compliance requirements and ethical standards. - Using Metasploit on a production server during business hours could disrupt critical healthcare operations and potentially impact patient care, which is never acceptable. - Claiming ethical exploitation is impossible is false - demonstrating vulnerabilities in controlled test environments is a standard practice in penetration testing. Simply telling clients to patch based on an assessment alone fails to meet the client's request for a demonstration of the risk.

Correct Answer: Clear-EventLog -LogName System

The command 'Clear-EventLog -LogName System' is the correct PowerShell command that attackers commonly use to clear Windows Event Logs, specifically the System log. This is a legitimate PowerShell cmdlet that completely erases all entries in the specified log, removing evidence of suspicious activities.

The other options are incorrect:

'Set-EventLogSize -LogName System -Size 0MB' is not a valid PowerShell cmdlet. There is no such command as 'Set-EventLogSize' in standard PowerShell.

'Remove-EventLog -LogName System -KeepIfNeeded' contains an invalid parameter. While 'Remove-EventLog' is a real PowerShell cmdlet, it's used to unregister an event source or delete a custom event log, not just clear entries. Additionally, 'KeepIfNeeded' is not a valid parameter for this cmdlet.

'Wevtutil.exe cl System && echo "Logs have been successfully cleared for maintenance purposes"' is a command line approach rather than a pure PowerShell command. While wevtutil.exe can indeed be used to clear logs (and is another technique attackers might use), the question specifically asks for a PowerShell command.

Correct Answer: type filename.txt:stream

In NTFS file systems, Alternate Data Streams (ADS) are a feature that allows files to contain additional data streams beyond the main data stream. These can be used to hide data by attaching it to normal files. The correct way to extract or view data from an ADS is using the 'type' command with the syntax 'type filename.txt:stream' where filename.txt is the host file and 'stream' is the name of the hidden data stream. The other options are incorrect: 'attrib -h -s filename.txt:stream' - This command modifies file attributes (hidden, system) but doesn't extract data from the stream. 'dir /a:h filename.txt:stream' - This command is used to list hidden files, not to extract or view the contents of a stream. 'more < filename.txt:stream' - This redirect syntax doesn't work with alternate data streams properly; the correct way is to use the 'type' command.