alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET WEB_CLIENT PDF With Hidden Embedded File"; flow:established,to_client; flowbits:isset,ET.pdf.in.http; file.data; content:"obj"; distance:0; content:"<<"; within:4; content:"/Embeddedfile"; distance:0; pcre:"/\x3C\x3C[^>]*\x2FEmbeddedfile/sm"; reference:url,blog.didierstevens.com/2009/07/01/embedding-and-hiding-files-in-pdf-documents/; classtype:bad-unknown; sid:2019850; rev:3; metadata:affected_product Web_Browsers, affected_product Web_Browser_Plugins, attack_target Client_Endpoint, created_at 2014_12_03, deployment Perimeter, signature_severity Major, tag Web_Client_Attacks, updated_at 2024_03_14;)