alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Bladabindi/njrat CnC Checkin"; flow:established,to_server; content:"|20 5b 20|"; content:"|20 5b 20|"; distance:0; content:"[endof]"; endswith; reference:md5,8db6655c0a5cb219c3bbc4bb5fc92e1a; classtype:command-and-control; sid:2033938; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_09_13, deployment Perimeter, malware_family njrat, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_09_13;)