alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"ET DELETED Generic Spambot (often Tibs) Post-Infection Checkin"; flow:established,to_server; content:"/access.php?"; http_uri; nocase; content:"w="; http_uri; nocase; content:"&a="; http_uri; nocase; content:"|0d 0a|Host|3a| "; pcre:"/Host\: \d+\.\d+\.\d+\.\d+\x0d\x0a/"; content:"|0d 0a|Cache-Control|3a| no-cache|0d 0a|"; content:!"|0d 0a|User-Agent|3a| "; classtype:trojan-activity; sid:2008174; rev:9; metadata:created_at 2010_07_30, signature_severity Unknown, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_08_22;)