alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET EXPLOIT_KIT Sundown EK Landing May 21 2015 M1"; flow:from_server,established; file_data; content:"|3c 21 2d 2d 20 53 45 45 44 3a|"; nocase; fast_pattern; content:"classid"; nocase; pcre:"/^\s*?=\s*?[\x22\x27](?:c|&#(?:x[64]3|99|67)\x3b)(?:l|&#(?:x[64]c|108|76)\x3b)(?:s|&#(?:x[75]3|115|83)\x3b)(?:i|&#(?:x[64]9|105|73)\x3b)(?:d|&#(?:x[64]4|100|68)\x3b)(?:\x3a|&#(?:x3a|58)\x3b)(?![a-fA-F0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12})[^\x22\x27]+(?:(?:\x5c|&#)(?:5[01234567]|10[012]|6[5678]|4[589]|9[789]|7[09])|(?:\x25|&#x)(?:4[123456]|6[123456]|3\d|2D))/Rsi"; classtype:exploit-kit; sid:2021136; rev:3; metadata:created_at 2015_05_22, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_10_08;)