alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET INFO SUSPCIOUS Non-standard base64 charset used for encoding"; flow:established,from_server; file_data; content:" & 15) << 4)"; fast_pattern; content:"(|22|"; content:!"|22|"; within:65; content:"|22|"; distance:65; within:1; content:!"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"; distance:-66; within:62; content:!"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; distance:-66; within:62; content:!"abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"; distance:-66; within:62; content:!"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; distance:-66; within:62; content:!"ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz"; distance:-66; within:62; content:!"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; distance:-66; within:62; flowbits:set,et.exploitkitlanding; classtype:bad-unknown; sid:2017364; rev:7; metadata:created_at 2013_08_21, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)