alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET POLICY PDF With Embedded File"; flow:established,to_client; file_data; content:"obj"; 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:2011507; rev:8; metadata:created_at 2010_09_28, confidence High, signature_severity Informational, updated_at 2019_07_26;)