SSH Configuration Interface. Design and Implementation of a “student self-service portal” for accessing to Linux-VMs

Bachelor Thesis , 2020 , 55 Pages , Grade: 1.7

Computer Science - Software

Secure Shell (SSH) is mainly used for managing most of the world’s web servers. It creates a secure channel on top of an unsecured network by using the client-server model. The problem arises with the increase in the number of clients that leads to a
corresponding increase in the maintenance work for the server administration. This thesis offers an insight into this problem and the solution to it. The SSH Configuration Interface (SSH CI) is one possible solution to simplify the process. It’s a client-server application that provides a simple but intuitive user interface (UI) to the users, so they can upload their public key directly to the server. The server thereon handles the request and, thus, excludes the need of an administration interaction from this process.

The SSH protocol uses encryption to secure the connection between a client and a server. It’s mainly used to log into a remote machine and execute commands, but there are other useful features available like tunneling and forwarding of Transmission Control Protocol (TCP) ports. An SSH connection supports multiple methods of authentication, the most common being the public key authentication. The advantage of it over a simple password, for example, is security and flexibility. Public key authentication provides a security level that even extremely long passwords can’t offer. In a situation where multiple users have access to the same account on the server by using SSH key authentication, it is easy to revoke access to any of them just by deleting their public key from the server. No password has to be shared across the users.

Contents

Acknowledgments

Abstract

1 Introduction

2 Technologies
2.1 Multitier Architecture
2.1.1 Back-end
2.1.2 Front-end
2.2 Persistence Layer
2.2.1 Novell's Library for LDAP
2.3 NLog Framework
2.4 Security Layer
2.5 Tools

3 Architecture
3.1 User Activity
3.2 Physical Deployment Model
3.3 Application Structure
3.3.1 MVC
3.3.2 Programming Model
3.3.3 Request Lifecycle
3.3.4 Dependency Injection
3.3.5 Improved Service Registration Mechanism
3.4 Data Access
3.4.1 Directory Service
3.4.2 Directory Service compared to DBMS
3.4.3 Authentication and Authorization
3.5 Configurations

4 Implementation
4.1 Hosting Environment
4.2 Error Handling
4.3 Logging
4.4 Identity Framework with LDAP
4.5 Key Storage Mechanism
4.6 Key Monitoring
4.7 Key Upload/Update
4.8 Key Delete

5 Security
5.1 Google reCaptcha v3
5.2 Open-Redirect Attack

6 Conclusion
6.1 Discussion

List of Code Snippets

List of Figures

Bibliography

• College: University of Applied Sciences Ulm
• Course: Computer Science
• Grade: 1.7
• Author: Gheorghe Mironica (Author)
• Publication Year: 2020
• Pages: 55
• Catalog Number: V1147465
• ISBN (eBook): 9783346527226
• ISBN (Book): 9783346527233
• Language: English
• Tags: C#, ASP.NET CORE, MVC, LDAP, SSH, Linux, VM, Directory Service, Full Stack