alert tcp-pkt $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/Unknown Grabber Base64 Data Exfiltration Attempt"; flow:established,to_server; content:"ewogICAgIkdyYWJiZXIiOiBbCiAgICAgICAgewogICAgICAgICAgICAiY29udGVudCI6IC"; startswith; fast_pattern; reference:md5,b299d80b538e24e8f5718501816b963e; classtype:trojan-activity; sid:2049441; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Windows_11, attack_target Client_Endpoint, created_at 2023_12_01, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_12_01; target:src_ip;)