alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed 3CX Supply Chain Attack User-Agent"; flow:established,to_server; http.user_agent; content:"Mozilla/5.0 (Windows NT 10.0|3b 20|Win64|3b 20|x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.5359.128 Safari/537.36"; bsize:116; fast_pattern; reference:url,www.volexity.com/blog/2023/03/30/3cx-supply-chain-compromise-leads-to-iconic-incident/; reference:url,twitter.com/patrickwardle/status/1641699867176374273; reference:url,objective-see.org/blog/blog_0x73.html; classtype:trojan-activity; sid:2044857; rev:1; metadata:attack_target Client_Endpoint, created_at 2023_03_31, deployment Perimeter, deployment SSLDecrypt, performance_impact Low, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_03_31, reviewed_at 2023_11_28; target:src_ip;)