During a penetration test for a client subject to the PCI DSS, you identify a service running on a system within the cardholder data environment that does not appear to be necessary for the processing, storage, or transmission of cardholder data. According to PCI DSS requirements, what is the BEST action to take?
Advocate for stronger encryption methods for stored cardholder data to offset any risks introduced by the service.
Review the terms within the Service Level Agreements (SLAs) regarding the operation of unauthorized services.
Perform a comprehensive asset inventory to confirm the presence of the service across the network.
Recommend the disabling of unnecessary services to comply with the principle of least functionality.
Suggest enhancing the intrusion detection system to monitor the unauthorized service closely.