alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE BlackMatter CnC Activity"; flow:established,to_server; http.request_line; content:"POST /?"; startswith; http.header; content:"Accept|3a 20|*/*|0d 0a|Connection|3a 20|keep-alive|0d 0a|Accept-Encoding|3a 20|gzip, deflate, br|0d 0a|Content-Type|3a 20|text/plain|0d 0a|User-Agent|3a 20|"; startswith; http.header_names; content:"|0d 0a|Accept|0d 0a|Connection|0d 0a|Accept-Encoding|0d 0a|Content-Type|0d 0a|User-Agent|0d 0a|Host|0d 0a|Content-Length|0d 0a|Cache-Control|0d 0a 0d 0a|"; bsize:104; http.user_agent; content:"/"; content:!"/"; distance:0; reference:md5,d0512f2063cbd79fb0f770817cc81ab3; classtype:command-and-control; sid:2033643; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_08_02, deployment Perimeter, malware_family DarkSide, performance_impact Low, confidence High, signature_severity Major, tag Ransomware, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_08_02;)