It is hard to believe a web form without a CAPTCHA. The web survival in this cut-throat competition is impossible without the mechanisms for blocking spam-boats. The spam-boats have now been made intelligent enough to break through machine printed CAPTCHAs. Handwritten CAPTCHA image can be one solution. In this paper handwritten CAPTCHA images have been used to enhance the web security. Introduction of randomness at various stages is proven to increase the recognition complexity for the spam boats, whereas the ease of recognition of handwritten words by human beings eventually increases the usefulness of such CAPTCHA. The technique used to produce colored image of handwritten letters also has randomness associated with it. The proposed CAPTCHA images contain alphanumeric content, one word with letters and a number with handwritten numerals. CAPTCHA images developed using proposed technique have been tested across various OCRs and online available resources as well.