alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET SHELLCODE Unicode UTF-8 Heap Spray Attempt"; flow:established,to_client; content:"u0"; nocase; content:"u0"; nocase; distance:1; within:2; content:"u0"; nocase; distance:1; within:2; content:"u0"; nocase; distance:1; within:2; pcre:"/u0[a-d]u0[a-d]u0[a-d]u0[a-d]/smi"; classtype:shellcode-detect; sid:2013319; rev:2; metadata:created_at 2011_07_27, confidence High, signature_severity Major, updated_at 2019_07_26;)