alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Iron Tiger DNSTunnel Retrieving CnC"; flow:established,from_server; file_data; content:"$$$$$$$$$$"; fast_pattern; pcre:"/^(?:#+[A-Z]+)?\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}(?:\x3a\d{1,5})?\${10}/R"; reference:md5,2c65085e7c71fa2c02c9b65e9b747e5b; reference:url,trendmicro.com/cloud-content/us/pdfs/security-intelligence/white-papers/wp-operation-iron-tiger.pdf; classtype:command-and-control; sid:2021789; rev:2; metadata:created_at 2015_09_17, signature_severity Major, updated_at 2019_07_26;)