alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Orca RAT URI Struct 4"; flow:established,to_server; http.uri; content:"=2/"; fast_pattern; pcre:"/^\/[A-Za-z0-9+~]+(?:=[1-2])?\/[A-Za-z0-9+~]+(?:=[1-2])?\/[A-Za-z0-9+~]+(?:=[1-2])?\/[A-Za-z0-9+~]+(?:=[1-2])?\/[A-Za-z0-9+~]+(?:=[1-2])?$/"; http.user_agent; pcre:"/(?: MSIE |rv\x3a11)/i"; http.header_names; content:!"Referer|0d 0a|"; content:!"Accept-Encoding|0d 0a|"; reference:url,pwc.blogs.com/cyber_security_updates/2014/10/orcarat-a-whale-of-a-tale.html; classtype:trojan-activity; sid:2019484; rev:5; metadata:created_at 2014_10_21, signature_severity Major, updated_at 2020_09_25;)