alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE HiddenTears Ransomware Activity (GET)"; flow:established,to_server; urilen:13; http.method; content:"GET"; http.uri; content:"/alertmsg.zip"; fast_pattern; http.host; content:".tk"; endswith; http.header_names; content:!"User-Agent"; content:!"Referer"; content:!"Accept"; reference:md5,eabb920f75c2943113713849878a6dfb; reference:md5,28b0ef0c832916a852ddf0c3c5427be3; classtype:trojan-activity; sid:2032320; rev:2; metadata:attack_target Client_Endpoint, created_at 2021_03_24, deployment Perimeter, malware_family Ransomware, confidence High, signature_severity Major, tag Ransomware, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_03_24, mitre_tactic_id TA0040, mitre_tactic_name Impact, mitre_technique_id T1486, mitre_technique_name Data_Encrypted_for_Impact;)