Abstract
Cloud computing is at the peak of its growth at current technological era has injected severe race among top IT companies to expand their offerings in cloud horizon on top of their premise-based solutions. To keep up with the rapid market demand enterprise software solution providers as Microsoft, Oracle, Google, Sales Force are aggressively releasing majority of their enterprise solutions under Software as a service (SaaS) module which on the other hand also increasing the security concerns. In context of SaaS where a consumer directly interacts with the cloud application one of the most vulnerable security threats is file upload from the client end, which is an active area of research. This paper aims to provide a single entry and exit principle base application programming interface (API) solution to this low discussed and signification risk imposing area of SaaS. In this paper we describe the security threats to file upload, review a range of protection rules and methods and propose a single entry, single exit principle oriented validation rule based API.