alert tcp any [21,25,110,143,443,465,587,636,989:995,5061,5222] -> $HOME_NET any (msg:"ET EXPLOIT FREAK Weak Export Suite From Server (CVE-2015-0204)"; flow:established,from_server; content:"|16 03|"; depth:2; byte_test:1,<,4,0,relative; content:"|02|"; distance:3; within:1; byte_jump:1,37,relative; content:"|00 29|"; within:2; fast_pattern; threshold:type limit,track by_dst,count 1,seconds 1200; reference:url,blog.cryptographyengineering.com/2015/03/attack-of-week-freak-or-factoring-nsa.html; reference:cve,2015-0204; reference:cve,2015-1637; classtype:bad-unknown; sid:2020665; rev:4; metadata:created_at 2015_03_11, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)