米GoogleウェブスパムチームのMatt Cutts氏は2012年4月16日、自身のTwitterアカウントにて、2万件以上のサイト管理者に対し、改ざんされたことを通知するメッセージを送付したことを明らかにした。
特に、不正なリダイレクトコードを埋め込まれた疑いのあるウェブマスターが対象。不正に埋め込まれたリダイレクトコードにより、訪問者が第三者の悪意あるウェブサイトに転送される恐れがある。
Dear site owner or webmaster of [site name],We are writing to let you know that we believe some of your website’s pages may be hacked. Specifically, we think that JavaScript has been injected into your site by a third party and may be used to redirect users to malicious sites. You should check your source code for any unfamiliar JavaScript and in particular any files containing "eval(function(p,a,c,k,e,r)". The malicious code may be placed in HTML, JavaScript or PHP files so it's important to be thorough in your search. The following are example URLs from your site where we found such content:
[URL]
[URL]
In addition, it's also possible your server configuration files (such as Apache's .htaccess) have been compromised. As a result of this, your site may be cloaking and showing the malicious content only in certain situations. We encourage you to investigate this matter in order to protect your visitors. If your site was compromised, it's important to not only remove the malicious (and usually hidden) content from your pages, but also to identify and fix the vulnerability. A good first step may be to contact your web host's technical support for assistance. It's also important to make sure that your website's software is up-to-date with the latest security updates and patches. More information about cleaning your site can be found at: Cleaning your site - Webmaster Tools Help
Sincerely, Google Search Quality Team
Cleaning your site
http://support.google.com/webmasters/bin/answer.py?hl=en&answer=163634
