## 4 Main Security and Privacy Challenges
### Cloud Paradigm Challenges  
Data loss, privacy leakage, multi-tenancy, unpermitted access to management platforms, Internet protocol, injection attacks are some of the main challenges faced in Cloud [95; 96]. Such challenges turn to make room for potential attacks, letting access control to cybercriminals, granting access to unauthorized services, therefore disclosing several classified data, if not all. Cloud computing faces enormous threats when involved with these vulnerabilities and thus affects business too, either directly or indirectly. One of the most reliable ways to repel threats and attacks is to identify any found and analyze the behavior properly. This section explains the different Cloud computing issues [97]. * Multi-tenancy is used in providing services to different customers and organizations with a particular software operating on the SaaS provider's servers within the architectural design. Every user company can use an application that is virtually designed in dividing data and configuring it virtually with the help of specially designed software. In this SaaS model, there is a high risk of vulnerability because clients turn to work with applications of multi-tenancy manufactured by Cloud Service Providers (CSP). The maximum-security of customer's data is the direct responsibility of the Cloud provider since sensitive information such as financial and individual data are hosted in their Cloud system [55]. Managing resources and scheduling work are some methods used by certain Cloud providers [98], but hardware potential is fully attained through virtualization by CSPs providers. Sandboxed setups refer to Virtual Machines (VM)being completely separate. Hardware sharing with the clients is considered safe according to this mindset. On the other hand, cybercriminals can gain access to the host when the sandboxed system has security setbacks [99]. The virtualization software is strongly recommended since it is capable of showing recent vulnerabilities in Cloud security, such as retrieving data by targeting a VM on one machine through attacks through cross-Virtual Machine side channel [100]. * Data Integrity: Security attention is greatly put on data integrity in the Cloud, which means any reply to a data request sent must be from someone with an access privilege. Establishing a general basic data integrity standard is important, though it is not still in place [101]. Trust is one of those many values that clients are expected to demonstrate in the computing facet. Today, a lot of companies or institutions encounter the issue of trust, and this hugely impacts the handling of their data [102]. * Unauthorized Access: One of the most vulnerable aspects of Cloud computing is giving unauthorized access to management platforms and resources. Users are exposed to this due to the shared technologies often involved in Cloud services. An acceptable way of mitigating the security solution of such a scenario is by introducing access control, and this helps in securing the client's personal information and its domain for privacy [103]. It is worth noting that cybercriminals can simply have unauthorized access to Cloud service systems because of a single-style authentication model and not very strong authentication mechanisms being used [104]. * Data loss and Leakage: The low cost of Cloud services is one reason customers turn to migrate to the Cloud, and it is warned that customers should pay attention to their important information since various diverse aspects can easily breach their data security. There is an increased chance of data leakage or loss due to high traffic and usage of the Cloud. The vulnerabilities and threats in Cloud service are undeniable, posing a great security threat to businesses and institutions. Significantly, it can be frustrating when you cannot retrieve and restore data after accidentally deleting files from the Cloud due to a lack of a backup system [105]. * Malicious Insider: Every organization has different rules and regulations regarding recruitment policies and employee information.