Design/Logic Flaw

BlockHosts before 2.0.4 does not properly parse (1) sshd and (2) vsftpd log files, which allows remote attackers to add arbitrary deny entries to the /etc/hosts.allow file and cause a denial of service by adding arbitrary IP addresses to a daemon log file, as demonstrated by connecting through ssh with a client protocol version identification containing an IP address string, or connecting through ftp with a username containing an IP address string, different vectors than CVE-2007-2765.