alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/Teslacrypt Ransomware HTTP CnC Beacon M2"; flow:established,to_server; http.method; content:"GET"; http.uri; content:".php?U3ViamVjdD1"; http.header_names; content:!"Accept"; content:!"Referer|0d 0a|"; reference:md5,c075fa8484d52c3978826c2f07ce9a9c; classtype:command-and-control; sid:2020718; rev:4; metadata:attack_target Client_Endpoint, created_at 2015_03_20, deployment Perimeter, malware_family Win32_Teslacrypt, signature_severity Major, tag c2, updated_at 2020_05_19, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)