Detailed Third-party attestation involves an external, independent party performing a network security assessment and providing documented proof, ensuring objectivity and compliance with regulatory or client requirements. Reference: CompTIA Security+ SY0-701 Study Guide, Domain 5: Security Program Management, Section: "Compliance and Security Audits".

The best answer is C. Firewall logs.
The PowerShell command shown is suspicious because it uses:
-exec bypass to bypass PowerShell execution policy
IEX (Invoke-Expression) to execute downloaded content in memory
Net.WebClient.DownloadString() to retrieve a remote script from the IP address 176.30.40.50 The question asks which logs will help confirm an established connection to that IP address. The best source for confirming that network communication actually occurred is firewall logs, because they record allowed and blocked inbound or outbound network connections between systems and remote IP addresses.
Why the other options are incorrect:
A . System event logsThese may show local operating system events, but they are not the best source for confirming a network connection to a specific external IP.
B . EDR logsEDR logs may show suspicious PowerShell execution and related behavior, and in some environments they may also show network activity. However, when the question specifically asks to confirm an established connection to a particular IP, firewall logs are the most direct and standard answer.
D . Application logsApplication logs generally track application-specific events and are not the best source for validating outbound network connections to a suspicious IP.
From a Security+ perspective, suspicious script execution should be correlated with network logs to validate command-and-control or malware download activity. That makes firewall logs the best choice.

Changing the default password for the local administrator account on a VPN appliance is a basic security measure that would have most likely prevented the unexpected login to the remote management interface. Default passwords are often easy to guess or publicly available, and attackers can use them to gain unauthorized access to devices and systems. Changing the default password to a strong and unique one reduces the risk of brute-force attacks and credential theft. Using least privilege, assigning individual user IDs, and reviewing logs more frequently are also good security practices, but they are not as effective as changing the default password in preventing the unexpected login. Reference: CompTIA Security+ Study Guide: Exam SY0-701, 9th Edition, page 116; Local Admin Accounts - Security Risks and Best Practices (Part 1)