Hackers are using a relatively new technique to lure users into visiting malicious websites. SEO poisoning is a method by which hackers can get a malicious link or URL, indexed by a search engine. When users search for terms that match the context of the malicious link, unsuspecting web surfers are often served malicious links which can divert them to harmful websites that commit all kinds of nasty deeds, ranging from ID theft to installing malware.
SEO poisoning is not new, but it is definitely a growing trend. It is becoming a vector of choice for hackers. The procedure to commit this crime is actually quite similar to the method of code-injection. First, find a vulnerability in the website or hosting infrastructure which will allow a hacker to upload malicious code or modify the behavior of the web application. Once this is achieved a hacker can insert URLs into a web page which will be indexed by search engines such as Google.
Below, we provide a screen shot to illustrate that hackers are reverse-engineering popular keywords from Google search trends to exploit unsuspecting users. In this particular example, the search query is extracted from Google Trends and results clearly show URLs which redirect users to fake anti-virus websites. Unfortunately, few of these URLs are even blacklisted by Google and hence users do not even have the luxury of making a decision to visit an unsafe website or not.
The aim of this experiment is to identify URLs which are using SEO poisoning.
Search results were collected from Google Trends. Once the search queries were collected, searches were performed via Google and the first 10 results were collected for each search query.
Each search result was analyzed to find whether the URLs displayed in the search results contained the complete search query in the exact same order. Also, it was determined whether the structure of the URL matched patterns of SEO poisoning. Furthermore, the IP associated with the URL was looked up on Spamcop to verify if the IP had been used for sending spam or had participated in zombie networks. Finally, using a geo-location API from IPinfo DB, the country of origin for the URL was determined. The test was conducted on March 23, 2010. Google trend results for the period of January 1, 2010 to March 22, 2010 were used for searches.
Note: 10,559 search results were analyzed.
Countries which seem to have the highest number of SEO poisoned links indexed by Google:
Note the fluctuations in the number of search results which are SEO poisoned.
It is clear that even the world’s most popular search engine company is not secure from SEO poisoning. It is not for the lack of trying though, but instead of the myriad number of ways hackers can break into a website and take advantage of it. We have seen that large numbers of search results match SEO poisoning patterns. Furthermore, it is clear that hackers are injecting malicious URLs into compromised websites to latch onto Google trends.