alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE APT29 Implant8 - Evil Twitter Callback"; flow:established,to_server; urilen:21; http.method; content:"GET"; http.uri; content:"/api/asyncTwitter.php"; fast_pattern; reference:url,www.us-cert.gov/security-publications/GRIZZLY-STEPPE-Russian-Malicious-Cyber-Activity; classtype:targeted-activity; sid:2023967; rev:4; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2017_02_17, deployment Perimeter, malware_family APT29_Implant8, performance_impact Low, confidence High, signature_severity Major, updated_at 2020_10_08;)