As the use of smart phones and tablet PCs has exploded in recent years

Portal site is not only providing search engine and e-mail service but also various services including blog, news, shopping, and others. The fact that average number of daily login for Korean portal site Naver is reaching 300 million suggests that many people are using portal sites. One of the most famous social network service, Facebook subscribers to reach 1.2 billion 30 million people at the time of the February 2014. With the increase in number of users followed by the diversity in types of services provided by portal sites and SNS, the attack is also increasing. Therefore, the objective of this study lies in analysing whole procedure of password authentication system of portal sites, SNS and analysing the security threat that may occur accordingly. Also, the security requirement corresponding to analysed security threat was extracted and the analysis on implementation of security requirements by portal sites and SNS was conducted.