alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Putty SSH Credential Stealer"; flow:to_server,established; http.method; content:"GET"; http.uri; content:".php?"; content:"=c3NoOi8v"; fast_pattern; pcre:"/=c3NoOi8v[A-Za-z0-9+/]+={0,2}$/"; http.header_names; content:!"Referer|0d 0a|"; reference:md5,b5c88d5af37afd13f89957150f9311ca; classtype:trojan-activity; sid:2021095; rev:4; metadata:created_at 2015_05_14, signature_severity Major, updated_at 2020_10_01;)