The Google search engine found at
http://www.google.com offers many features, including language and document translation; web, image, newsgroups, catalog, and news searches; and more. These features offer obvious benefits to even the most uninitiated web surfer, but these same features offer far more nefarious possibilities to the most malicious Internet users, including hackers, computer criminals, identity thieves, and even terrorists. This article outlines the more harmful applications of the Google search engine, techniques that have collectively been termed "Google hacking." The intent of this article is to educate web administrators and the security community in the hopes of eventually stopping this form of information leakage. This document is an excerpt of the full Google Hacker's Guide published by Johnny Long, and located at
http://johnny.ihackstuff.com.
Basic Search Techniques
Since the Google web interface is so easy to use, I won't describe the basic functionality of the
http://www.google.com web page. Instead, I'll focus on the various operators available:
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Use the plus sign (+) to force a search for an overly common word. Use the minus sign (-) to exclude a term from a search. No space follows these signs.
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To search for a phrase, supply the phrase surrounded by double quotes (" ").
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A period (.) serves as a single-character wildcard.
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An asterisk (*) represents any word—not the completion of a word, as is traditionally used.
Google advanced operators help refine searches. Advanced operators use a syntax such as the following:
operator:search_term
Notice that there's no space between the operator, the colon, and the search term.
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The site: operator instructs Google to restrict a search to a specific web site or domain. The web site to search must be supplied after the colon.
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The filetype: operator instructs Google to search only within the text of a particular type of file. The file type to search must be supplied after the colon. Don't include a period before the file extension.
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The link: operator instructs Google to search within hyperlinks for a search term.
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The cache: operator displays the version of a web page as it appeared when Google crawled the site. The URL of the site must be supplied after the colon.
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The intitle: operator instructs Google to search for a term within the title of a document.
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The inurl: operator instructs Google to search only within the URL (web address) of a document. The search term must follow the colon.
