You can detect Pi-hole applications using this tool.
Pi-hole or Pihole is a Linux network-level advertisement and Internet tracker blocking application which acts as a DNS sinkhole and optionally a DHCP server, intended for use on a private network. It is designed for low-power embedded devices with network capability, such as the Raspberry Pi, but supports any Linux machines. Pi-hole has the ability to block traditional website advertisements as well as advertisements in unconventional places, such as smart TVs and mobile operating system advertisements.
If attackers detect the technology used, they will try to detect vulnerabilities related to this application.
Only use components that do not have known vulnerabilities, only use components that when combined to not introduce a security vulnerability, and ensure that a misconfiguration does not cause any vulnerabilities.