alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET WEB_CLIENT Possible Microsoft Internet Explorer Use-After-Free (CVE-2013-3897)"; flow:established,from_server; file_data; content:"onpropertychange"; fast_pattern; nocase; content:".execCommand("; nocase; pcre:"/^[\r\n\s]*?[\x27\x22]Unselect[\x27\x22]/Rsi"; content:"appendChild("; nocase; content:"textarea"; nocase; content:".select("; nocase; content:".onselect"; reference:cve,2013-3897; classtype:attempted-user; sid:2017572; rev:7; metadata:affected_product Web_Browsers, affected_product Web_Browser_Plugins, attack_target Client_Endpoint, created_at 2013_10_08, deployment Perimeter, confidence Low, signature_severity Major, tag Web_Client_Attacks, tag CISA_KEV, updated_at 2022_07_05;)