alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET EXPLOIT_KIT CottonCastle EK URI Struct"; flow:established,to_server; http.uri; content:"/3/"; fast_pattern; pcre:"/\/3\/(?:M[ABCDFGHIJKMOPSTUZ]|E[ABDEGIJKMNPRSVY]|R[ABCEFGHIKLMNPST]|G[ABCEGKMNPSTUV]|A[BCGLMNPQSUVZ]|O[ABCDFIJMNRST]|S[ABEGILMPRSUW]|T[ABEGHILMPSTY]|N[BCGHIKMPSTV]|I[ABCFGKLNSV]|L[ABCGIMNPST]|W[ABCGKMPRTZ]|Z[ABCDKMNSTU]|F[ABCGMNPTW]|H[BCEGKMPST]|K[CDFHLMPST]|U[ACGHLMNRV]|Y[BCGKLMPSU]|C[CELMNSTV]|D[ABCGIMST]|V[BCLMST]|J[BDFST]|P[GJKMN]|Q[ABGIM]|B[BGLS]|X[ACMS])\/[a-f0-9]{32}(?:\.[^\x2f]+|\/\d+\.\d+\.\d+\.\d+\/?)?$/"; classtype:exploit-kit; sid:2018534; rev:7; metadata:created_at 2014_06_05, deprecation_reason Relevance, confidence High, signature_severity Major, updated_at 2024_03_07, reviewed_at 2024_03_07;)