I had discovered something funny today. So, I have Kali Linux and I am trying to fully update the system using the repo http://http.kali.org/kali. All is good and well until I get 403 denied for backdoor-factory and mimikatz. At first I thought it was a server configuration error and so ignored it, but then I got curious and decided to pop the URLs into Firefox. Sure enough, my university blocks these specific URLs, but not anything else in the repo.
I decided to check out if I could load the URLs in https (yes, I knew it was a long shot as most (afaik) APT servers don't even support https at all) and found out it does work, but only when accepting the certificate for archive-8.kali.org. (yes, I know invalid certs aren't good, but I figured if it is using GPG to check the validity and it uses http with no encryption anyway, then why not).
Also, I know I can just use https://archive-8.kali.org/kali in place of the old url and have done so, but the reason I asked about accepting invalid certs is for if this solution of just switching domains is impossible.