The ability to provide reliable data rates across the several intended coverage areas has made massive multiple-input multiple-output (m-MIMO) cell-free (CF) a crucial technology for future sixth-generation (6G) systems. However, CF networks also introduce new vulnerabilities, specifically in terms of security and network integrity. For that, to complement the conventional cryptographic algorithms, physical layer security (PLS) can be an effective strategy for acquiring essential wireless network information in order to create important authentication mechanisms against spoofing attacks. To this end, we propose leveraging the wireless channel and the access point selection (APS) allocation schemes as authentication methods to prevent network attacks that attempt to impersonate legitimate user communications. Our results show that monitoring these parameters provides valuable insights about the network performance and the impact under active eavesdropping influence. Consequently, this approach enables a statistical detection of illegitimate spoofing attempts through alarms, which can be further reinforced by upper-layer authentication protocols to enhance the security performance of wireless networks.