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 way to determine whether unauthorized changes have been made to production programs is to use source code comparison software to compare the current version of the programs with the previous version or the approved version. This will identify any changes that have been made without proper authorization or documentation. Tracing PCRs to logs or vice versa will only verify that the authorized changes have been recorded, but not detect any unauthorized changes. References: Standards, Guidelines, Tools and Techniques
- ISACA, section "IS Audit and Assurance Tools and Techniques"

The auditor should first escalate to audit management to discuss the audit plan. This is because the audit plan should be based on a risk assessment and aligned with the organization's objectives and strategies. The auditor should not accept the CIO's request without proper justification and approval from the audit management, who are responsible for ensuring the audit plan's quality and independence. The auditor should also communicate the potential risks and implications of not conducting IS audits in the upcoming year, such as missing new or emerging threats, vulnerabilities, or compliance issues. References:
* CISA Review Manual (Digital Version), Chapter 2, Section 2.11
* CISA Online Review Course, Domain 1, Module 1, Lesson 22

The best approach from a risk management perspective when implementing a large and complex data center IT infrastructure is to use a deployment plan based on sequenced phases, as this will allow the organization to break down the project into manageable and measurable stages, and to monitor and control the progress, quality, and outcomes of each phase12. A phased deployment plan can also help to reduce the risks of errors, failures, or disruptions that could affect the entire infrastructure, and to implement corrective actions or contingency plans as needed34.
References
1: Data Center Project Planning: A Guide to Success2 2: Data Center Project Planning: A Guide to Success4 3: Data Center Migration: A Step-by-Step Guide3 4: Data Center Migration: A Step-by-Step Guide1

To reduce false positive alerts, it is essential to carefully configure a limited set of rules tailored to the organization's specific data loss prevention needs. This ensures that the DLP tool accurately identifies true positives and reduces the occurrence of false alarms.
References
* ISACA CISA Review Manual 27th Edition, Page 304-305 (DLP Tool Configuration)