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Articles : Blocking PDF spam

The new wave of spam with PDF in attachment started flooding the inboxes. To get past spam filters, the actual text within the body of the spam e-mail is empty or contains nonsensical phrases. AntispamSniper plugins have enough features for blocking this new kind of spam:

  • To get rid of PDF spam add the mask "pdf" to the black list of attachment types (Filtering | Attachments | File types). Only whitelisted senders will be able to send to you PDF documents in attachment. The messages from unknown senders with PDF in attachment will be blocked.

  • Since version the plugins allow using rules for filtering messages by attachment headers. Here are the examples of black rules for blocking PDF spam:

    This rule blocks all messages with attached PDF.

    Header{Content-Type} =~ \.pdf

    This rule with two conditions blocks the messages with PDF document in attachment and empty body (two cases are recognized: when a message contains no text/html part or its body contains only spaces).

    Header{Content-Type} =~ \.pdf
    Body =~ ^\s*$

    Use this rule to block the messages without the "keyword" string in subject and with attached PDF.

    Header{Content-Type} =~ \.pdf
    Not Header{Subject} =~ keyword

    See more information on using the rules.

  • The plug-in automatically calculates the checksums for message attachments. Once it was trained on a message with attached PDF, the plug-in blocks new messages with the same document in attachment automatically.