alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE APT15/NICKEL Related CnC Activity (POST)"; flow:established,to_server; http.request_line; content:"POST /?newfrs"; startswith; fast_pattern; content:"setssion="; distance:0; http.header_names; content:!"Referer"; http.accept; content:"Accept|3a 20|"; reference:md5,95507bd09d464582e82ed0b2fdf46a31; reference:md5,8a5e766065ea81d1470e4955f0c7f402; reference:url,www.microsoft.com/security/blog/2021/12/06/nickel-targeting-government-organizations-across-latin-america-and-europe/; classtype:trojan-activity; sid:2034645; rev:2; metadata:attack_target Client_Endpoint, created_at 2021_12_08, deployment Perimeter, malware_family APT15, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_02_16;)