An IS auditor is conducting a review of a data center. An observation that could indicate an access control issue is muddy footprints directly inside the emergency exit. Access control is a process that ensures that only authorized entities or individuals can access or use an information system or resource, and prevents unauthorized access or use. Access control can be implemented using various methods or mechanisms, such as physical, logical, administrative, etc. Muddy footprints directly inside the emergency exit could indicate an access control issue, as they could suggest that someone has entered the data center through the emergency exit without proper authorization or authentication, and potentially compromised the security or integrity of the data center. Security cameras deployed outside main entrance is not an observation that could indicate an access control issue, but rather a control that could enhance access control, as security cameras are devices that capture and record video footage of the surroundings, and can help monitor and deter unauthorized access or activity. Antistatic mats deployed at the computer room entrance is not an observation that could indicate an access control issue, but rather a control that could prevent static electricity damage, as antistatic mats are devices that dissipate or reduce static charges from people or objects, and can help protect electronic equipment from electrostatic discharge (ESD). Fencing around facility is two meters high is not an observation that could indicate an access control issue, but rather a control that could improve physical security, as fencing is a barrier that encloses or surrounds an area, and can help prevent unauthorized entry or intrusion.

The greatest concern that the IS auditor should have when reviewing an organization's security information and event management (SIEM) solution is that the SIEM is decentralized. This is because a decentralized SIEM can pose challenges for collecting, correlating, analyzing and reporting on security events and incidents from multiple sources and locations. A decentralized SIEM can also increase the complexity and cost of maintaining and updating the SIEM components, as well as the risk of inconsistent or incomplete security monitoring and response. The IS auditor should recommend that the organization adopts a centralized or hybrid SIEM architecture that can provide a holistic and integrated view of the security posture and activities across the organization. The other findings are not as concerning as a decentralized SIEM, because they can be addressedby implementing best practices and standards for SIEM reporting and configuration. References: CISA Review Manual (Digital Version)1, Chapter 5, Section 5.2.4

Signature-based intrusion detection systems (IDS) are systems that compare network traffic with predefined patterns of known attacks, called signatures. The effectiveness of signature-based IDS depends on how well they can detect new or unknown attacks that are not in their signature database. Therefore, an increase in the number of detected incidents not previously identified is the best indicator of the effectiveness of signature-based IDS, as it shows that they can recognize novel or modified attacks.

The best recommendation for an organization that is unable to add new servers on demand in a cost-efficient manner is to build a virtual environment. A virtual environment is a technology that allows multiple virtual machines to run on a single physical server, sharing its resources and capabilities. A virtual environment can help the organization add new servers on demand in a cost-efficient manner by reducing the need for hardware acquisition, maintenance, and power consumption. The other options are not as effective as building a virtual environment, as they do not address the root cause of the problem or provide the same benefits.
Increasing the capacity of existing systems is a short-term solution that can help improve the performance and availability of the current servers, but it does not enable the organization to add new servers on demand in a cost-efficient manner. Upgrading hardware to newer technology is a costly solution that can help enhance the functionality and reliability of the servers, but it does not enable the organization to add new servers on demand in a cost-efficient manner. Hiring temporary contract workers for the IT function is an irrelevant solution that can help supplement the IT staff's skills and knowledge, but it does not enable the organization to add new servers on demand in a cost-efficient manner. References: CISA Review Manual (Digital Version), Chapter 3, Section 3.3.1