alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE MSIL/TrojanDownloader.Small.CLJ CnC Activity"; flow:established,to_server; http.start; content:"GET /"; startswith; content:"|20|HTTP/1.1|0d 0a|Referer|3a 20|Microsoft|20|Windows|20|"; fast_pattern; http.user_agent; content:"@"; http.header_names; content:"|0d 0a|Referer|0d 0a|User-Agent|0d 0a|Host|0d 0a|Connection|0d 0a 0d 0a|"; bsize:43; reference:md5,fb7f916531e239c8a705249d93b48598; classtype:trojan-activity; sid:2032328; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_03_25, deployment Perimeter, malware_family MSIL_TrojanDownloader_Small_CLJ, performance_impact Low, confidence High, signature_severity Major, tag Downloader, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_03_25;)