alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET EXPLOIT_KIT Hello/LightsOut EK Secondary Landing"; flow:established,to_server; content:".php?a="; http_uri; fast_pattern:only; content:"&f="; http_uri; content:"&u="; http_uri; pcre:"/\.php\?a=[^&]+&f=[a-f0-9]{32}&u=[^&]+$/I"; reference:url,vrt-blog.snort.org/2014/03/hello-new-exploit-kit.html; reference:url,blogs.cisco.com/security/watering-hole-attacks-target-energy-sector/; classtype:exploit-kit; sid:2018206; rev:2; metadata:created_at 2014_03_05, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)