In my University, the network is protected by Cyberroam Firewall and we are provided a login page through which we access internet and the login page isn't secured.It sends out the userid and password unencrypted in the network. From past few days, someone has been changing my passwords. And I think someone is performing MITM and stealing credentials. How do I figure out if this is the case and protect it ?
You do not need to concern it is Cyberroam Firewall or other brands of firewall. Different firewall products always have the similar functionality. What you should know is the configuration & functionality of firewall.
Functionality: Actually, you should understand the original objective of firewall. Pure firewall is only used to filter different network activities (e.g. IP addresses, port numbers, transmission direction, payload applications, etc.). User ID and password encryption is not the mission of pure firewall, but protected by secure channel methods (e.g. VPN). The truth is: many modern products have combine firewall, IDS/IPS, VPN, anti-virus,etc. functions together into a single product. You buy different packages with different prices. Hence, first, you should know whether your Cyberroam firewall has the channel encryption function.
Configuration: if your firewall has the channel encryption function, you need to know how it is configured. In your case, userid and password are sent in plaintext. Hence, this firewall may not include channel encryption function or not configure/activate encryption. In addition, only network-level integrated firewall has the capability to do such encryption.
What you should do to prevent this - Report to your network administration. (one solution is encrypt information before sending. However, you use the common login page. Encryption on your own is not feasible.)