Which of the following does the IOC system not perform?

The correct answer reflects the functionality that the IOC (Indicator of Compromise) system is not designed to perform. Specifically, the IOC system is focused on detecting and providing information related to potential security incidents by identifying patterns or signatures of known threats on compromised devices or within log data.

When it comes to adjusting firewall rules, this is typically outside the scope of an IOC system's primary role. Firewalls operate based on predefined rules and protocols for managing traffic flow and enforcing security policies, and while an IOC system may inform the firewall about potential threats, it does not inherently modify the rules themselves. Instead, systems responsible for firewall management would use information provided by IOCs to adjust their configurations based on established security policies and practices.

In contrast, the other functionalities—providing a consolidated view of compromised devices, comparing IOC signatures with existing logs, and detecting suspicious web page usage—are indeed within the realm of what an IOC system does. These tasks help organizations to monitor, analyze, and respond to security threats more effectively.