Google and other search engines are taking steps to stop the abuse. For example, Google has stopped certain kinds of searches that could yield a trove of Social Security numbers in a single swoop. It also puts limits on the number of search requests sent per minute, which can slow down mass searches for vulnerable Web sites.
In reality, it just forces hackers to be a bit more patient. Putting limits on search also hurts security professionals who want to do automated daily searches of their Web sites for problems, Shulman said.
Shulman said he's seen another kind of attack called "site masking," which causes a legitimate Web site to simply disappear from search results.
Google's search engine penalises sites that have duplicate content and will drop one from its index. Hackers can take advantage of this by creating a Web site that has a link to a competitor's Web page but is filtered through a proxy server.
Google indexes the content under the proxy's domain. If this is done enough times with more proxy servers, Google will consider the targeted Web page a duplicate and drop it from its index.
One way Web site administrators can defend against this is barring their Web site from being indexed by anything other than the legitimate IP address of a search engine, Shulman said.