The default configuration of mod_perl for Apache as installed on Mandrake Linux 6.1 through 7.1 sets the /perl/ directory to be browseable, which allows remote attackers to list the contents of that directory.
https://exchange.xforce.ibmcloud.com/vulnerabilities/5257
https://euvd.enisa.europa.eu/vulnerability/EUVD-2000-0870
http://www.securityfocus.com/bid/1678
http://archives.neohapsis.com/archives/bugtraq/2000-09/0111.html