alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Possible IndigoDrop/Cobalt Strike Download"; flow:established,to_client; http.stat_code; content:"200"; file.data; content:"XHhmY1x4ZThceDg5XHgwMFx4MDBceDAwXHg2MFx4ODlceGU1X"; depth:49; fast_pattern; isdataat:!5000,relative; reference:url,blog.talosintelligence.com/2020/06/indigodrop-maldocs-cobalt-strike.html; classtype:trojan-activity; sid:2030400; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_06_26, deployment Perimeter, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_06_26;)