Has been found a security vulnerability in Zabbix Client allowing to execute OS commands, even if EnableRemoteCommands is set to "0". This was tested on Zabbbix 1.6.5. The IP address check is not bypassed, so the attacker must come from (or spoof) a valid Zabbix Server. This bug exists only in FreeBSD and Solaris agents.
In ./src/libs/zbxsysinfo/(freebsd|solaris)/net.c, a user defined variable "param" is used to create "command" which is executed.
$> echo "net.tcp.listen[80';id >/tmp/ID ; echo ']"|nc testbox 10050
This will execute "id" on the client and write the result to /tmp/ID.