Searching for "Classified" Content in Documents

Sensitive government and military organizations classify their documents with familiar terms like "TOP SECRET" and also less well known terms like "NOFORN" (which means the data can't be shared with any foreign nationals).

These terms and phrases are usually placed in the headers and footers of every page in electronic documents. Most organizations that deal with extremely sensitive data have mandatory requirements for documents to be labeled according to their classification levels.

Nessus Direct Feed users can scan network servers for these types of documents with a new audit policy available on the Tenable Support Portal. The "Classified Documents" .audit file searches Word and Adobe files for many common keywords used in the US government and NATO to indicate the classification level of the document.

Modifying the policy to audit for specific code words is also very simple. Below is an example simple search for the word "TOP SECRET":

<item>
        type: FILE_CONTENT_CHECK
        description: "Server is hosting TOP SECRET level documents"
        file_extension: "pdf" | "doc"
        regex: "TOP SECRET"
        expect: "TOP SECRET"
    max_size : "3k"
</item>

Often, classified programs receive their own codeword. Documents from a program named "TENABLE" would be labeled "TOP SECRET TENABLE". If we wanted to modify the default policy "TOP SECRET" policy to look for two or more specific program code we could run an audit with this type of logic:

<item>
        type: FILE_CONTENT_CHECK
        description: "Server is hosting TS codeword level documents"
        file_extension: "pdf" | "doc"
        regex: "TOP SECRET (NESSUS|TENABLE|UFO|ELVIS)"
        expect: "TOP SECRET"
    max_size : "3k"
</item>

The new regular expression would look for documents from the various programs named NESSUS, TENABLE, UFO and ELVIS. 

To learn more about how countries around the world classify their sensitive data, please read this Wikipedia entry. To learn more about the Nessus Direct Feed, please visit our web site or consider watching one of the Nessus demonstration videos.