For a short while today, Google classified all results as harmful, several people reported. Basically no matter which URL you saw in the search results... they all had the text “This site may harm your computer” printed above the snippet. Clicking on the result in Google would yield the advisory page usually reserved for malware-infested websites only. The interstitial reads:
<<Warning – visiting this web site may harm your computer!
• Return to the previous page and pick another result.
• Try another search to find what you’re looking for.
Or you can continue to [URL] at your own risk>>
According to Google, this bug lasted around 40 minutes for any particular user (within a time frame of 55 minutes) before it was fixed. Google by now blogged about it, saying:
We periodically receive updates to that list and received one such update to release on the site this morning. Unfortunately (and here’s the human error), the URL of ’/’ was mistakenly checked in as a value to the file and ’/’ expands to all URLs. Fortunately, our on-call site reliability team found the problem quickly and reverted the file. Since we push these updates in a staggered and rolling fashion, the errors began appearing between 6:27 a.m. and 6:40 a.m. and began disappearing between 7:10 and 7:25 a.m., so the duration of the problem for any particular user was approximately 40 minutes.>>
The StopBadware blog says that the glitch “led to a denial of service of our website, as millions of Google users attempted to visit our site for more information.” For the future, Google say they will put up “more robust file checks” to prevent such things in the future.
What happened? Very simply, human error. Google flags search results with the message "This site may harm your computer" if the site is known to install malicious software in the background or otherwise surreptitiously. We do this to protect our users against visiting sites that could harm their computers. through both manual and automated methods. We work with a non-profit called StopBadware.org to come up with criteria for maintaining this list, and to provide simple processes for webmasters to remove their site from the list.