alert http1 $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Andromeda Checkin"; flow:established,to_server; http.method; content:"POST"; nocase; http.content_type; bsize:33; content:"application/x-www-form-urlencoded"; http.header; content:"User-Agent|3a 20|Mozilla/4.0|0d 0a|"; fast_pattern; http.content_len; byte_test:0,>,60,0,string,dec; byte_test:0,<,150,0,string,dec; http.connection; bsize:5; content:"close"; http.request_body; pcre:"/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})([\r\n](?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4}))?$/i"; http.header_names; content:!"|0d 0a|Referer|0d 0a|"; content:!"|0d 0a|Accept"; reference:md5,41c33fdb9a95353a3b109393543f90dd; classtype:command-and-control; sid:2016223; rev:15; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2012_03_30, deployment Perimeter, performance_impact Moderate, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_07, reviewed_at 2024_03_19;)