alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE TA453 Related Activity (POST)"; flow:established,to_server; http.method; content:"POST"; http.header; content:"Content-type|3a 20|application/x-www-form-urlencoded|0d 0a|"; http.uri; content:"/Api/"; startswith; http.request_body; content:"Data="; startswith; http.header_names; content:!"Referer"; content:"|0d 0a|Content-type|0d 0a|Content-length|0d 0a|"; fast_pattern; reference:url,research.checkpoint.com/2022/apt35-exploits-log4j-vulnerability-to-distribute-new-modular-powershell-toolkit/; classtype:trojan-activity; sid:2034889; rev:3; metadata:attack_target Client_Endpoint, created_at 2022_01_11, deployment Perimeter, deployment SSLDecrypt, malware_family APT35, malware_family CharmingKitten, malware_family Phosphorus, performance_impact Significant, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_04;)