Cyber-squatting is fast becoming a threat to the future viability of Internet commerce. Fraudulent abuse of domain name registration is at the core of cybersquatting. By registering domain names similar to famous brands, cybersquatters lure consumers into purchasing counterfeit products, cause them to reveal their personally identifiable information, and expose themselves to spyware. Typosquatting is registering domain names that are typographical mistakes on popular and common domains. To the best of our knowledge, no solution has been proposed to thwart typosquatting. In this paper, we propose and implement Anti Typo Squatting Tool (ATST), an extension to Internet browsers that could detect and warn users of any possible typos. Through extensive analysis and evaluation, we show that ATST can detect up to 85% of user typos. Further, ATST is lightweight, and is able to check for typos and provide possible suggestions in as little as 300ms.