PDFassassin

PDFassassin is a PDF module created for the purpose of combating PDF spam. With the rapid increase in the use of PDF files for spamming, the module was developed to allow for their scanning. This module works by examining the email body upon connection and checking for PDF attachments. The text content is then extracted from the file using the pdftotext tool and is scanned by the SpamAssassin engine. If the PDF contains images, the gocr binary will be called to extract the text content. The overall spam score of the PDF is compared against the global required_score setting. If it surpasses it, a score equal to the one specified in pdf.cf (which is by default set at 10) will be appended to the overall score of the email message.

This is a different approach, as it scans the content against the SpamAssassin engine, rather than using a word list filter. To use this module, pdftotext and gocr are required. To install, copy the Pdf.pm and pdf.cf files to the SpamAssassin configuration directory. In @Mail installations, it is in /usr/local/atmail/spamassassin/etc/, and in default Linux installations, it is in /etc/mail/spamassassin. The SpamAssassin configuration files must be 'linted' afterwards using: $ /usr/local/atmail/spamassassin/bin/spamassassin -D --lint.

After a successful installation, you should be able to scan PDF attachments via SpamAssassin. The pdf.cf file can be edited to change the scoring of PDF spam emails. The score definition can then be edited as required: score PDF 10.0.

This initial release implements the module for SpamAssassin which scans the content of PDF attachments in email messages and appends the spam score to that of the originating email message.