The line printer daemon (lpd) in the lpr package in multiple Linux operating systems authenticates by comparing the reverse-resolved hostname of the local machine to the hostname of the print server as returned by gethostname, which allows remote attackers to bypass intended access controls by modifying the DNS for the attacking IP.

The line printer daemon (lpd) in the lpr package in multiple Linux operating systems authenticates by comparing the reverse-resolved hostname of the local machine to the hostname of the print server as returned by gethostname, which allows remote attackers to bypass intended access controls by modifying the DNS for the attacking IP.