alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Possible Covenant Framework Grunt MSBuild Stager HTTP Download"; flow:established,to_client; file_data; content:"System.IO.Compression.CompressionMode.Decompress"; content:"System.Reflection.Assembly.Load("; distance:0; content:".EntryPoint.Invoke("; distance:0; fast_pattern; content:"|3c 2f|UsingTask|3e|"; distance:0; reference:url,github.com/cobbr/Covenant; reference:url,posts.specterops.io/entering-a-covenant-net-command-and-control-e11038bcf462; classtype:trojan-activity; sid:2027798; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_08_04, deployment Perimeter, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_08_04;)