alert udp $EXTERNAL_NET any -> $HOME_NET 161 (msg:"GPL SNMP null community string attempt"; content:"|04 01 00|"; depth:15; offset:5; reference:bugtraq,2112; reference:bugtraq,8974; reference:cve,1999-0517; classtype:misc-attack; sid:2101892; rev:7; metadata:created_at 2010_09_23, cve CVE_1999_0517, signature_severity Major, updated_at 2019_07_26;)