alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET WEB_CLIENT Likely Malicious PDF Containing StrReverse"; flow:established,to_client; content:"%PDF-"; content:"StrReverse|28|"; distance:0; nocase; classtype:bad-unknown; sid:2011246; rev:4; metadata:affected_product Web_Browsers, affected_product Web_Browser_Plugins, attack_target Client_Endpoint, created_at 2010_07_30, deployment Perimeter, confidence Medium, signature_severity Major, tag Web_Client_Attacks, updated_at 2019_07_26;)